Richtige Fernseher haben Röhren!

Richtige Fernseher haben Röhren!

In Brief: On this site you will find pictures and information about some of the electronic, electrical and electrotechnical technology relics that the Frank Sharp Private museum has accumulated over the years .

Premise: There are lots of vintage electrical and electronic items that have not survived well or even completely disappeared and forgotten.

Or are not being collected nowadays in proportion to their significance or prevalence in their heyday, this is bad and the main part of the death land. The heavy, ugly sarcophagus; models with few endearing qualities, devices that have some over-riding disadvantage to ownership such as heavy weight,toxicity or inflated value when dismantled, tend to be under-represented by all but the most comprehensive collections and museums. They get relegated to the bottom of the wants list, derided as 'more trouble than they are worth', or just forgotten entirely. As a result, I started to notice gaps in the current representation of the history of electronic and electrical technology to the interested member of the public.

Following this idea around a bit, convinced me that a collection of the peculiar alone could not hope to survive on its own merits, but a museum that gave equal display space to the popular and the unpopular, would bring things to the attention of the average person that he has previously passed by or been shielded from. It's a matter of culture. From this, the Obsolete Technology Tellye Web Museum concept developed and all my other things too. It's an open platform for all electrical Electronic TV technology to have its few, but NOT last, moments of fame in a working, hand-on environment. We'll never own Colossus or Faraday's first transformer, but I can show things that you can't see at the Science Museum, and let you play with things that the Smithsonian can't allow people to touch, because my remit is different.

There was a society once that was the polar opposite of our disposable, junk society. A whole nation was built on the idea of placing quality before quantity in all things. The goal was not “more and newer,” but “better and higher" .This attitude was reflected not only in the manufacturing of material goods, but also in the realms of art and architecture, as well as in the social fabric of everyday life. The goal was for each new cohort of children to stand on a higher level than the preceding cohort: they were to be healthier, stronger, more intelligent, and more vibrant in every way.

The society that prioritized human, social and material quality is a Winner. Truly, it is the high point of all Western civilization. Consequently, its defeat meant the defeat of civilization itself.

Today, the West is headed for the abyss. For the ultimate fate of our disposable society is for that society itself to be disposed of. And this will happen sooner, rather than later.

OLD, but ORIGINAL, Well made, Funny, Not remotely controlled............. and not Made in CHINA.

How to use the site:

- If you landed here via any Search Engine, you will get what you searched for and you can search more using the search this blog feature provided by Google. You can visit more posts scrolling the left blog archive of all posts of the month/year,
or you can click on the main photo-page to start from the main page. Doing so it starts from the most recent post to the older post simple clicking on the Older Post button on the bottom of each page after reading , post after post.

You can even visit all posts, time to time, when reaching the bottom end of each page and click on the Older Post button.

- If you arrived here at the main page via bookmark you can visit all the site scrolling the left blog archive of all posts of the month/year pointing were you want , or more simple You can even visit all blog posts, from newer to older, clicking at the end of each bottom page on the Older Post button.
So you can see all the blog/site content surfing all pages in it.

- The search this blog feature provided by Google is a real search engine. If you're pointing particular things it will search IT for you; or you can place a brand name in the search query at your choice and visit all results page by page. It's useful since the content of the site is very large.

Note that if you don't find what you searched for, try it after a period of time; the site is a never ending job !

Every CRT Television saved let revive knowledge, thoughts, moments of the past life which will never return again.........

Many contemporary "televisions" (more correctly named as displays) would not have this level of staying power, many would ware out or require major services within just five years or less and of course, there is that perennial bug bear of planned obsolescence where components are deliberately designed to fail and, or manufactured with limited edition specificities..... and without considering........picture......sound........quality........

..............The bitterness of poor quality is remembered long after the sweetness of todays funny gadgets low price has faded from memory........ . . . . . .....
Don't forget the past, the end of the world is upon us! Pretty soon it will all turn to dust!

Have big FUN ! !

©2010, 2011, 2012, 2013, 2014 Frank Sharp - You do not have permission to copy photos and words from this blog, and any content may be never used it for auctions or commercial purposes, however feel free to post anything you see here with a courtesy link back, btw a link to the original post here , is mandatory.
All sets and apparates appearing here are property of
Engineer Frank Sharp. NOTHING HERE IS FOR SALE !

Wednesday, September 18, 2013



The  PHILIPS  I12T620  PORTOFINO AUTOMATIC was First real little 12 inches portable B/W television from PHILIPS in 1969.

First fully transistorized television chassis for PHILIPS portable set allowing relatively light weight and comfort.

The mechanical turret approach to television tuning has been used almost exclusively for the past 60 years. Even though replete with the inherent disadvantages of mechanical complexity, unreliability and cost, such apparatus has been technically capable of performing its intended function and as a result the consumer has had to bear the burdens associated with the device. However, with the " recent "  Broadcast demands for parity of tuning for UHF and VHF channels, the increasing number of UHF and cable TV stations have imposed new tuning performance requirements which severely tax the capability of the mechanical turret tuner. Consequently, attempts are now being made to provide all electronic tuning to meet the new requirements.

The set has rotary selector for both VHF and UHF channels and this selector was called "Speed Tuning" allowing continuous tuning search for all stations. Pushing down the button allows fast band exploration, releasing it allows normal fine tuning search.

The set can be powered from 12volt source or normal way via mains 220V.

Semiconductors and the televison technology reality changing......................

So far the history of television development has been entirely radio (and picture) valves centric. And it would stay so for another decade. In the background, however, an entirely new development was taking shape: semiconductors. Especially the concept of semiconductor diodes was not entirely new. 
During the war both in Germany and the US some diodes were developed as detector in radar systems, but they remained exotic. In 1946 the US war effort on these type of materials was published and available to its allies in a 28-volume overview. At Philips Research this triggered one group under dr. Piet Haaijman in the sector of Herre Rinia to a few researchers working on metal-based detectors, using such materials as selenium and germanium. These activities came into a completely new perspective when in 1947 the the transistor was invented by John Bardeen, Walter Brattain and William Shockley of Bell Labs. This sent a shock through the world of electronics, and also within Philips kicked off semiconductor research. In 1948 Evert Verweij, one of the three NatLab directors, visited the US and concluded that research should be focused on germanium as base material. 
The group of Haaijman was extended to accelerate the work on germanium diodes, whereas a second group under F. Stieltjes started work on the transistor. One of the young researchers in this group was J. Tummers, who would be the leading developer of transistors within Research. Especially the transistor was a hard nut to crack, and progress was slow, also because Bell Labs had disclosed only a minimum of details on the engineering of their transistor, while also the US Department of Defence pushed hard to keep it top secret. It was only by 1952, with the famous Bell Licensees Symposium, that Bell Labs shared the "transistor cook book" to a selected set of companies with which it has cross-license agreements. From Europe this included Philips, Siemens, AEG-Telefunken and GEC. So far the NatLab had worked on the point-contact transistor, but these were very sensitive and unreliable, and after the Bell Symposium they switched to grown junction transistors.

Quite quickly after the announcement of the transistor invention it became clear to the Philips management that this was an important development that the company could not ignore. By 1949 the research activities of the group of Piet Haaijman resulted in what was thought to be a producible germanium diode. At this point the HIG Elektronenbuizen decided it would create a dedicated Industriegroep Halfgeleiders (Industrial Group Semiconductors) with their HIG. On the one hand this was to give it the proper attention and focus, on the other hand it was to protect the radio valve group from distraction, giving its massive effort to role out the new families of television valves. At this time Jan van Vessem had succeeded Gerrit Alma as head of the Radiobuizen Labs, while ir H. Hazeu was the technical director of the HIG after Theo Tromp moved to the Philips board of directors in 1946. Hazeu and Tromp got along very well, and jointly pushed innovation, the importance of radio valves and picture tubes, but also recognized the importance and opportunities of semiconductors. Leader of the semiconductor activities became dr. Jan van der Spek. A production facility was built in Eindhoven and in 1950 the first products were delivered; the OA70 and OA50 diodes. The OA70 used germanium with a higher conductivity and consequently had a high bandwidth, making it fit for video detection. The OA50 was made or "regular" germanium and was a low frequency detector, so suitable for audio or synchronization signal detection. Because production was still unstable, the output was "binned" with lesser products sold as OA51, OA52 and OA56. By 1952 they were succeeded by the OA60 and OA61. Almost as soon as they appeared the germanium diodes were used by the Apparaten Lab for the functions as described. They were part of the TX1422 platform released in 1952, and thus in commercial sets from 1953.

As soon as the first generation diodes came available the company struggled with production capacity. The small-scale Eindhoven production facility was soon too small, and a second site was opened in Heerlen, but even that was not sufficient to cope with the demand. By the end of 1952 the pressure increased when, after the Bell Symposium, better transistors were in development. In a policy meeting where neither Tromp nor Hazeu were present especially the NatLab representative Herre Rinia proposed a massive switch from radio valves to semiconductors, with 50% of the HIG Elektronenbuizen R&D budget to be allocated to semiconductors. When he heard this Hazeu was shocked, and together with Tromp was able to reverse the decision. But it was decided that the HIG would put more resources into semiconductor development. Furthermore the Philips board gave the green light for the construction of a brand new large semiconductor factory in Nijmegen, construction of which was started immediately. It was also decided that all semiconductor developments were to be concentrated in Nijmegen too. By 1955 this plant had grown to 1100 employees, of which 122 in development.
Transistor developments in the meantime proved more problematic.
 The NatLab had, after initial work on point contact transistors, switched to the so-called growth or double-doping transistors, based on the information obtained after the Bell Symposium. By the end of 1952 they had made 100 transistors and proposed these be taken into production by the IG Halfgeleiders. The director of the Radiobuizen Lab Jan van Vessem and his staff were, however, not convinced of the reproducibility of this technology.
Van Vessem was convinced that the RCA technology of alloy junction transistors was much better. 
Due to rather blunt behaviour by Philips in the negotiations it took almost a year to obtain the desired license from RCA. 
Although a three first transistors were announced already in 1953, the OC10 to OC12, these were hardly producible and effectively never cae beyond the sample status. 
The first production transistors out of Nijmegen were the OC70 and OC71. Both were germanium PNP transistors in a glass encapsulation, suitable for audio and other low frequency applications, and launched in 1954. However, where the germanium diodes were adopted very quickly, it would take much longer for transistors to appear in the Philips television and we won't see them in the next platforms.

Koninklijke Philips Electronics N.V. (Royal Philips Electronics Inc.), most commonly known as Philips, (Euronext: PHIA, NYSE: PHG) is a multinational Dutch electronics corporation.

Philips is one of the largest electronics companies in the world. In 2009, its sales were €23.18 billion. The company employs 115,924 people in more than 60 countries.

Philips is organized in a number of sectors: Philips Consumer Lifestyles (formerly Philips Consumer Electronics and Philips Domestic Appliances and Personal Care), Philips Lighting and Philips Healthcare (formerly Philips Medical Systems).
he company was founded in 1891 by Gerard Philips, a maternal cousin of Karl Marx, in Eindhoven, Netherlands. Its first products were light bulbs and other electro-technical equipment. Its first factory survives as a museum devoted to light sculpture. In the 1920s, the company started to manufacture other products, such as vacuum tubes (also known worldwide as 'valves'), In 1927 they acquired the British electronic valve manufacturers Mullard and in 1932 the German tube manufacturer Valvo, both of which became subsidiaries. In 1939 they introduced their electric razor, the Philishave (marketed in the USA using the Norelco brand name).
Philips was also instrumental in the revival of the Stirling engine.

As a chip maker, Philips Semiconductors was among the Worldwide Top 20 Semiconductor Sales Leaders.

In December 2005 Philips announced its intention to make the Semiconductor Division into a separate legal entity. This process of "disentanglement" was completed on 1 October 2006.

On 2 August 2006, Philips completed an agreement to sell a controlling 80.1% stake in Philips Semiconductors to a consortium of private equity investors consisting of Kohlberg Kravis Roberts & Co. (KKR), Silver Lake Partners and AlpInvest Partners. The sale completed a process, which began December 2005, with its decision to create a separate legal entity for Semiconductors and to pursue all strategic options. Six weeks before, ahead of its online dialogue, through a letter to 8,000 of Philips managers, it was announced that they were speeding up the transformation of Semiconductors into a stand-alone entity with majority ownership by a third party. It was stated then that "this is much more than just a transaction: it is probably the most significant milestone on a long journey of change for Philips and the beginning of a new chapter for everyone – especially those involved with Semiconductors".

In its more than 115 year history, this counts as a big step that is definitely changing the profile of the company. Philips was one of few companies that successfully made the transition from the electrical world of the 19th century into the electronic age, starting its semiconductor activity in 1953 and building it into a global top 10 player in its industry. As such, Semiconductors was at the heart of many innovations in Philips over the past 50 years.

Agreeing to start a process that would ultimately lead to the decision to sell the Semiconductor Division therefore was one of the toughest decisions that the Board of Management ever had to make.

On 21 August 2006, Bain Capital and Apax Partners announced that they had signed definitive commitments to join the expanded consortium headed by KKR that is to acquire the controlling stake in the Semiconductors Division.

On 1 September 2006, it was announced in Berlin that the name of the new semiconductor company founded by Philips is NXP Semiconductors.

Coinciding with the sale of the Semiconductor Division, Philips also announced that they would drop the word 'Electronics' from the company name, thus becoming simply Koninklijke Philips N.V. (Royal Philips N.V.).


The foundations of Philips were laid in 1891 when Anton and Gerard Philips established Philips & Co. in Eindhoven, the Netherlands. The company begun manufacturing carbon-filament lamps and by the turn of the century, had become one of the largest producers in Europe. Stimulated by the industrial revolution in Europe, Philips’ first research laboratory started introducing its first innovations in the x-ray and radio technology. Over the years, the list of inventions has only been growing to include many breakthroughs that have continued to enrich people’s everyday lives.

In the early years of Philips &; Co., the representation of the company name took many forms: one was an emblem formed by the initial letters of Philips ; Co., and another was the word Philips printed on the glass of metal filament lamps.

One of the very first campaigns was launched in 1898 when Anton Philips used a range of postcards showing the Dutch national costumes as marketing tools. Each letter of the word Philips was printed in a row of light bulbs as at the top of every card. In the late 1920s, the Philips name began to take on the form that we recognize today.

The now familiar Philips waves and stars first appeared in 1926 on the packaging of miniwatt radio valves, as well as on the Philigraph, an early sound recording device. The waves symbolized radio waves, while the stars represented the ether of the evening sky through which the radio waves would travel.

In 1930 it was the first time that the four stars flanking the three waves were placed together in a circle. After that, the stars and waves started appearing on radios and gramophones, featuring this circle as part of their design. Gradually the use of the circle emblem was then extended to advertising materials and other products.

At this time Philips’ business activities were expanding rapidly and the company wanted to find a trademark that would uniquely represent Philips, but one that would also avoid legal problems with the owners of other well-known circular emblems. This wish resulted in the combination of the Philips circle and the wordmark within the shield emblem.

In 1938, the Philips shield made its first appearance. Although modified over the years, the basic design has remained constant ever since and, together with the wordmark, gives Philips the distinctive identity that is still embraced today.

The first steps of CRT production by Philips started in the thirties with the Deutsche Philips Electro-Spezial gesellschaft in Germany and the Philips NatLab (Physics laboratory) in Holland. After the introduction of television in Europe, just after WWII there was a growing demand of television sets and oscilloscope equipment. Philips in Holland was ambitious and started experimental television in 1948. Philips wanted to be the biggest on this market. From 1948 there was a small Philips production of television and oscilloscope tubes in the town of Eindhoven which soon developed in mass production. In 1976 a part of the Philips CRT production went to the town of Heerlen and produced its 500.000'th tube in 1986. In 1994 the company in Heerlen changed from Philips into CRT-Heerlen B.V. specialized in the production of small monochrome CRT's for the professional market and reached 1.000.000 produced tubes in 1996. In this stage the company was able to produce very complicated tubes like storage CRT's.
In 2001 the company merged into Professional Display Systems, PDS worked on LCD and Plasma technology but went bankrupt in 2009. The employees managed a start through as Cathode Ray Technology which now in 2012 has to close it's doors due to the lack of sales in a stressed market. Their main production was small CRT's for oscilloscope, radar and large medical use (X-ray displays). New experimental developments were small Electron Microscopy, 3D-TV displays, X-Ray purposes and Cathode Ray Lithography for wafer production. Unfortunately the time gap to develop these new products was too big.

28 of September 2012, Cathode Ray Technology (the Netherlands), the last Cathode Ray Tube factory in Europe closed. Ironically the company never experienced so much publicity as now, all of the media brought the news in Holland about the closure. In fact this means the end of mass production 115 years after Ferdinand Braun his invention. The rapid introduction and acceptation of LCD and Plasma displays was responsible for a drastic decrease in sales. Despite the replacement market for the next couple of years in the industrial, medical and avionics sector.
The numbers are small and the last few CRT producers worldwide are in heavy competition.

Gerard Philips:

Gerard Leonard Frederik Philips (October 9, 1858, in Zaltbommel – January 27, 1942, in The Hague, Netherlands) was a Dutch industrialist, co-founder (with his father Frederik Philips) of the Philips Company as a family business in 1891. Gerard and his younger brother Anton Philips changed the business to a corporation by founding in 1912 the NV Philips' Gloeilampenfabrieken. As the first CEO of the Philips corporation, Gerard laid with Anton the base for the later Philips multinational.

Early life and education

Gerard was the first son of Benjamin Frederik David Philips (1 December 1830 – 12 June 1900) and Maria Heyligers (1836 – 1921). His father was active in the tobacco business and a banker at Zaltbommel in the Netherlands; he was a first cousin of Karl Marx.


Gerard Philips became interested in electronics and engineering. Frederik was the financier for Gerard's purchase of the old factory building in Eindhoven where he established the first factory in 1891. They operated the Philips Company as a family business for more than a decade.

Marriage and family

On March 19, 1896 Philips married Johanna van der Willigen (30 September 1862 – 1942). They had no children.

Gerard was an uncle of Frits Philips, whom he and his brother brought into the business. Later they brought in his brother's grandson, Franz Otten.

Gerard and his brother Anton supported education and social programs in Eindhoven, including the Philips Sport Vereniging (Philips Sports Association), which they founded. From it the professional football (soccer) department developed into the independent Philips Sport Vereniging N.V.

Anton Philips:

Anton Frederik Philips (March 14, 1874, Zaltbommel, Gelderland – October 7, 1951, Eindhoven) co-founded Royal Philips Electronics N.V. in 1912 with his older brother Gerard Philips in Eindhoven, the Netherlands. He served as CEO of the company from 1922 to 1939.

Early life and education

Anton was born to Maria Heyligers (1836 – 1921) and Benjamin Frederik David Philips (December 1, 1830 – June 12, 1900). His father was active in the tobacco business and a banker at Zaltbommel in the Netherlands. (He was a first cousin to Karl Marx.) Anton's brother Gerard was 16 years older.


In May 1891 the father Frederik was the financier and, with his son Gerard Philips, co-founder of the Philips Company as a family business. In 1912 Anton joined the firm, which they named Royal Philips Electronics N.V.

During World War I, Anton Philips managed to increase sales by taking advantage of a boycott of German goods in several countries. He provided the markets with alternative products.

Anton (and his brother Gerard) are remembered as being civic-minded. In Eindhoven they supported education and social programs and facilities, such as the soccer department of the Philips Sports Association as the best-known example.

Anton Philips brought his son Frits Philips and grandson Franz Otten into the company in their times. Anton took the young Franz Otten with him and other family members to escape the Netherlands just before the Nazi Occupation during World War II; they went to the United States. They returned after the war.

His son Frits Philips chose to stay and manage the company during the occupation; he survived several months at the concentration camp of Vught after his workers went on strike. He saved the lives of 382 Jews by claiming them as indispensable to his factory, and thus helped them evade Nazi roundups and deportation to concentration camps.

Philips died in Eindhoven in 1951.

Marriage and family

Philips married Anne Henriëtte Elisabeth Maria de Jongh (Amersfoort, May 30, 1878 – Eindhoven, March 7, 1970). They had the following children:

* Anna Elisabeth Cornelia Philips (June 19, 1899 – ?), married in 1925 to Pieter Franciscus Sylvester Otten (1895 – 1969), and had:
o Diek Otten
o Franz Otten (b. c. 1928 - d. 1967), manager in the Dutch electronics company Philips
* Frederik Jacques Philips (1905-2005)
* Henriëtte Anna Philips (Eindhoven, October 26, 1906 – ?), married firstly to A. Knappert (d. 1932), without issue; married secondly to G. Jonkheer Sandberg (d. September 5, 1935), without issue; and married thirdly in New York City, New York, on September 29, 1938 to Jonkheer Gerrit van Riemsdijk (Aerdenhout, January 10, 1911 – Eindhoven, November 8, 2005). They had the following children:
o ..., Jonkheerin Gerrit van Riemsdijk (b. Waalre, October 2, 1939), married at Waalre on February 17, 1968 to Johannes Jasper Tuijt (b. Atjeh, Koeta Radja, March 10, 1930), son of Jacobus Tuijt and wife Hedwig Jager, without issue
o ..., Jonkheerin Gerrit van Riemsdijk (b. Waalre, April 3, 1946), married firstly at Calvados, Falaise, on June 6, 1974 to Martinus Jan Petrus Vermooten (Utrecht, September 16, 1939 – Falaise, August 29, 1978), son of Martinus Vermooten and wife Anna Pieternella Hendrika Kwantes, without issue; married secondly in Paris on December 12, 1981 to Jean Yves Louis Bedos (Calvados, Rémy, January 9, 1947 – Calvados, Lisieux, October 5, 1982), son of Georges Charles Bedos and wife Henriette Louise Piel, without issue; and married thirdly at Manche, Sartilly, on September 21, 1985 to Arnaud Evain (b. Ardennes, Sedan, July 7, 1952), son of Jean Claude Evain and wife Flore Halleux, without issue
o ..., Jonkheerin Gerrit van Riemsdijk (b. Waalre, September 4, 1948), married at Waalre, October 28, 1972 to Elie Johan François van Dissel (b. Eindhoven, October 9, 1948), son of Willem Pieter
Jacob van Dissel and wife Francisca Frederike Marie Wirtz, without issue.

(To see the Internal Chassis Just click on Older Post Button on bottom page, that's simple !)

A comment...........of a 1996 reality ..................
Philips, which seems to be a perennial walking wounded case. The company had appeared to be on the mend after a worldwide cost- cutting programme which was started five years ago when Jan Timmer took over as chairman.
 But, following a sharp profits fall, with the company's first quarterly loss since 1992, a further shake up is being undertaken.
The difficulty is that the company operates in a mature market, in which prices are falling at an annual rate of six per cent. Manufacturers are competing by cutting costs to gain a larger share of static demand. It's not a situation in which any firm that does its own manufacturing can achieve much. Philips' latest plan involves an overall loss of 6,000 jobs in its consumer electronics business, with far greater reliance placed on a group of external suppliers which are referred to as "a cluster of dedicated subcontractors".

This is an approach that was pioneered many years ago by major Japanese manufacturers. Rather than make everything yourself, you rely on subcontractors who, in return, rely on you for their main source of work. It is hardly a cosy arrangement: the whole point seems to be that the major fain can exert pressure on its subcontractors, thereby - in theory - achieving optimum efficiency and cost-effectiveness. What happens when lower and lower prices are demanded for subcontracted work is not made clear.

The whole edifice could collapse. However that might be, this is the course on which Philips has now embarked. The company is also to carry out distribution, sales and marketing on a regional rather than a national basis, and has said that it will not support Grundig's losses after this year.

But Philips' chief financial officer Dudley Eustace has said that it has "no intention of abandoning the television and audio business". One has to assume that the subcontracting will also be done on an international basis, as major Japanese firms have had to do. There is a sense of déjà vu about this, though one wishes Philips well - it is still one of the major contributors to research and development in our industry.

Toshiba, which has also just appointed a new top man, Taizo Nishimoro, provides an interesting contrast. Mr Nishimoro thinks that the western emphasis on sales and marketing rather than engineering is the way to go. So the whole industry seems to be moving full circle. Taizo Nishimoro has become the first non engineering president of Toshiba. Where the company cannot compete effectively on its own, he intends to seek international alliances or go for closures. He put it as follows. "The technology and the businesses we are engaged in are getting more complex.
 In these circumstances, if we try to do everything ourselves we are making a mistake." Here's how Minoru Makihara, who became head of Mitsubishi Corporation four years ago, sees it. "Technologies are now moving so fast that it is impossible for the top manager to know all the details. 
Companies are now looking for generalists who can understand broad changes, delegate and provide leadership." Corporate change indeed amongst our oriental colleagues. Major firms the world over are facing similar problems and having to adopt similar policies.
In a mature market such as consumer electronics, you have to rely on marketing to squeeze the last little bit of advantage from such developments as Dolby sound and other added value features. The consumer electronics industry has been hoping that the digital video disc would come to its aid and get sales and profits moving ahead.
The DVD was due to be released in Sept 1996 , but we are unlikely to hear much more about it yet awhile. There's no problem with the technology: the difficulty is with licensing and software. There is obviously no point in launching it without adequate software support. But the movie companies, which control most of the required supply of software, are concerned that a recordable version of the disc, due in a couple of years' time, would be a gift to pirates worldwide. Concessions have been made by the electronics industry, in particular that different disc formats should be used in different parts of the world. But a curious problem has arisen.
 The other main use of the DVD is as a ROM in computer systems. For this application flexible copying facilities are a major requirement. But the movie companies are unwilling to agree to this. At present the situation is deadlocked and the great hope of an autumn launch, all important for sales, has had to be postponed. Next year maybe? It's a great pity, since the DVD has much to offer.
There's a lot of sad news on the retail side as well. Colorvision has been placed in administrative receivership, with a threat to 800 jobs at its 76 stores, while the Rumbelows shops that were taken over by computer retailer Escom have suffered a similar fate. The receivers have closed down the UK chain with the loss of 850 jobs at some 150 stores. Nothing seems to be going right just now.


The tuning circuits has a large knob potentiometers tuning system which use voltage controlled capacitances such as varactor diodes as the frequency determining elements.

Therefore a stable AFC circuit is developed:

A superheterodyne receiver having an automatic intermediate frequency control circuit with means to prevent the faulty regulation thereof. The receiver has means for receiving a radio frequency signal and mixing the same with the output of a superheterodyne oscillator. This produces an intermediate frequency signal which is coupled to a frequency or phase discriminator to produce an error signal for controlling the frequency of the superheterodyne oscillator. A regulation circuit is provided having an electronic switch to interrupt the feedback circuit when only unwanted frequencies tend to produce faulty regulation of the superheterodyne oscillator.

Power supply is realized with mains transformer and Linear transistorized power supply stabilizer, A DC power supply apparatus includes a rectifier circuit which rectifies an input commercial AC voltage. The rectifier output voltage is smoothed in a smoothing capacitor. Voltage stabilization is provided in the stabilizing circuits by the use of Zener diode circuits to provide biasing to control the collector-emitter paths of respective transistors.A linear regulator circuit according to an embodiment of the present invention has an input node receiving an unregulated voltage and an output node providing a regulated voltage. The linear regulator circuit includes a voltage regulator, a bias circuit, and a current control device.

In one embodiment, the current control device is implemented as an NPN bipolar junction transistor (BJT) having a collector electrode forming the input node of the linear regulator circuit, an emitter electrode coupled to the input of the voltage regulator, and a base electrode coupled to the second terminal of the bias circuit. A first capacitor may be coupled between the input and reference terminals of the voltage regulator and a second capacitor may be coupled between the output and reference terminals of the voltage regulator. The voltage regulator may be implemented as known to those skilled in the art, such as an LDO or non-LDO 3-terminal regulator or the like.
The bias circuit may include a bias device and a current source. The bias device has a first terminal coupled to the output terminal of the voltage regulator and a second terminal coupled to the control electrode of the current control device. The current source has an input coupled to the first current electrode of the current control device and an output coupled to the second terminal of the bias device. A capacitor may be coupled between the first and second terminals of the bias device.
In the bias device and current source embodiment, the bias device may be implemented as a Zener diode, one or more diodes coupled in series, at least one light emitting diode, or any other bias device which develops sufficient voltage while receiving current from the current source. The current source may be implemented with a PNP BJT having its collector electrode coupled to the second terminal of the bias device, at least one first resistor having a first end coupled to the emitter electrode of the PNP BJT and a second end, a Zener diode and a second resistor. The Zener diode has an anode coupled to the base electrode of the PNP BJT and a cathode coupled to the second end of the first resistor. The second resistor has a first end coupled to the anode of the Zener diode and a second end coupled to the reference terminal of the voltage regulator. A second Zener diode may be included having an anode coupled to the cathode of the first Zener diode and a cathode coupled to the first current electrode of the current control device.
A circuit is disclosed for improving operation of a linear regulator, having an input terminal, an output terminal, and a reference terminal. The circuit includes an input node, a transistor, a bias circuit, and first and second capacitors. The transistor has a first current electrode coupled to the input node, a second current electrode for coupling to the input terminal of the linear regulator, and a control electrode. The bias circuit has a first terminal for coupling to the output terminal of the linear regulator and a second terminal coupled to the control electrode of the transistor. The first capacitor is for coupling between the input and reference terminals of the linear regulator, and the second capacitor is for coupling between the output and reference terminals of the linear regulator. The bias circuit develops a voltage sufficient to drive the control terminal of the transistor and to operate the linear regulator. The bias circuit may be a battery, a bias device and a current source, a floating power supply, a charge pump, or any combination thereof. The transistor may be implemented as a BJT or FET or any other suitable current controlled device.

- The EHT Output is realized with a selenium rectifier.

The EHT selenium rectifier which is a Specially designed selenium rectifiers were once widely used as EHT rectifiers in television sets and photocopiers. A layer of selenium was applied to a sheet of soft iron foil, and thousands of tiny discs (typically 2mm diameter) were punched out of this and assembled as "stacks" inside ceramic tubes. Rectifiers capable of supplying tens of thousands of volts could be made this way. Their internal resistance was extremely high, but most EHT applications only required a few hundred microamps at most, so this was not normally an issue. With the development of inexpensive high voltage silicon rectifiers, this technology has fallen into disuse.A selenium rectifier is a type of metal rectifier, invented in 1933. They were used to replace vacuum tube rectifiers in power supplies for electronic equipment, and in high current battery charger applications.

The photoelectric and rectifying properties of selenium were observed by C. E. Fitts around 1886 but practical rectifier devices were not manufactured routinely until the 1930s. Compared with the earlier copper oxide rectifier, the selenium cell could withstand higher voltage but at a lower current capacity per unit area.


LUXOR 5134 TYPE 18051341 YEAR 1984.

The  LUXOR  5134  TYPE 18051341  is a  20 inches (51cm) color television with 29 programs PLL synthesized tuning.

Was first LUXOR model featuring the AV SCART socket.

A SCART Connector (which stands for Syndicat des Constructeurs d'Appareils Radiorécepteurs et Téléviseurs) is a standard for connecting audio-visual equipment together. The official standard for SCART is CENELEC document number EN 50049-1. SCART is also known as Péritel (especially in France) and Euroconnector but the name SCART will be used exclusively herein. The standard defines a 21-pin connector (herein after a SCART connector) for carrying analog television signals. Various pieces of equipment may be connected by cables having a plug fitting the SCART connectors. Television apparatuses commonly include one or more SCART connectors.
Although a SCART connector is bidirectional, the present invention is concerned with the use of a SCART connector as an input connector for receiving signals into a television apparatus. A SCART connector can receive input television signals either in an RGB format in which the red, green and blue signals are received on Pins 15, 11 and 7, respectively, or alternatively in an S-Video format in which the luminance (Y) and chroma (C) signals are received on Pins 20 and 15. As a result of the common usage of Pin 15 in accordance with the SCART standard, a SCART connector cannot receive input television signals in an RGB format and in an S-Video format at the same time.
Consequently many commercially available television apparatuses include a separate SCART connectors each dedicated to receive input television signals in one of an RGB format and an S-Video format. This limits the functionality of the SCART connectors. In practical terms, the number of SCART connectors which can be provided on a television apparatus is limited by cost and space considerations. However, different users wish the input a wide range of different combinations of formats of television signals, depending on the equipment they personally own and use. However, the provision of SCART connectors dedicated to input television signals in one of an RGB format and an S-Video format limits the overall connectivity of the television apparatus. Furthermore, for many users the different RGB format and S-Video format are confusing. Some users may not understand or may mistake the format of a television signal being supplied on a given cable from a given piece of equipment. This can result in the supply of input television signals of an inappropriate format for the SCART connector concerned.
This kind of connector is todays obsoleted !

This LUXOR  5134  TYPE 18051341  model series was introducing at the time the PLL synthesizer tuning system first time Microcomputer controlled with direct channel calling feature even from remote control. The PLL frequency synthesized electronic tuning system provides free and easy channel selection. and lets you tune directly to any chan-
nel using the channel number buttons (0~9 and key) on the front keyboard control !!

The  LUXOR  5134  TYPE 18051341 was featuring fist time The TDA3300 Motorola's third generation colour processing,The device will accept a PAL or NTSC composite video
signal and output the. three colour signals needing only a simple
driver amplifier to interface with the picture tube ,Furthermore it features first time the Automatic Black Level set-up.

First LUXOR TV model series featuring a monocarrier chassis horizontally placed for all functions.

Most TV manufacturers appear to be heading towards a common goal when it comes to designing a new chassis for future production. The idea which makes the most sense is to design a single chassis which will drive a variety of tube sizes, is easily adapted to suit different broadcasting standards (this makes exporting that much easier) and is capable of add-ons, e.g. teletext facilities. This approach reduces manufacturing costs by having a single production line for one p.c.b. containing all the common items. The production sequence then "forks" to allow for the different versions of the chassis, e.g. different components are required for 90° and 110° c.r.t.s. This type of design tends to suit smaller manufacturers. The Swedish company Luxor recently introduced their "unified" chassis design, the SX9. Luxor's total output is relatively modest and they identified their main market as being at the luxury end. It made sense therefore to develop a single chassis with as much built-in flexibility as possible.


 Luxor AB KONSUMENTELEKTRONIK was a Swedish home electronics and computer manufacturer located in Motala, acquired by Nokia in 1985.

Originally a manufacturer of tape recorders, radios, television sets, stereo systems, and other home electronics, it launched its first home computer, the ABC 80 in 1978. The succeeding ABC 800 series was introduced in 1981 with new releases in 1983 being produced until the ABC line was terminated in 1986.

r.i.p.   SWEDEN...................


The LUXOR  5134  TYPE 18051341  CHASSIS  B3-1 (SX9) was first monocarrier horizontal placed chassis from this firm and was first introducing several features in one board pcb.

TDA2594 -- SYNC
SAB3035 -- CITAC

The SX9 is essentially a single -board design (the p.c.b. measures 14in. by 9in.) which of course is designed to facilitate automatic insertion of components, and incorporates frequency synthesis tuning as standard. A block diagram of the receiver is shown in Fig. 1. Starting with the power supply, this is a self -oscillating switch -mode type based on the Siemens design but incorporating the Siemens TDA4600 i.c. providing base current control to a BU208 transistor.
 The most important difference is that the Luxor SX9 uses a mains isolated version. There are two versions of the line output stage: one suitable for 90° c.r.t.s and another for 110°. The 90° type uses a diode -split transformer which provides 24kV of e.h.t. The 110° type uses a conventional transformer/ tripler combination and provides 25kV e.h.t. The most interesting aspect is the use of a 110° deflection tube with a pincushion -distortion free yoke. This is the first time that we have seen this type of tube in use. It obviates the need for the usual diode modulator, and width control is provided by a simple adjustable coil in series with the line scan coils as in the 90° version. Vertical deflection is taken care of by an SGS-Ates i.c. type TDA1670. This is a development of the well known TDA1170 but housed in a higher power vertically - mounted pack, and offers greater output stage current capability with thermal shutdown protection and an extended blanking pulse generator which effectively suppresses all non -active lines, including the teletext lines. The sync generator/line oscillator uses a PHILIPS TDA2594 which is a later generation PHILIPS TDA2593 with the exception that it offers sound mute when the oscillator is not locked by incoming sync (e.g. when the receiver is not tuned to a station). This feature is a legal requirement for new receivers in some countries, W. Germany for example, and we are going to encounter it frequently from now on.
Turning to the signals side, the chassis uses a combined v.h.f./u.h.f. tuner as standard. The tuner has an integral +256 prescaler i.c. which provides the necessary local oscillator signal for the frequency synthesis tuning section. The if output from the tuner is amplified by a Plessey SL1431 i.c. which provides an a.g.c. signal for the tuner without the need for the usual a.g.c. takeover point preset. This i.c. provides a balanced output which drives a Surface Acoustic Wave Filter.
The filter is unusual in that it has two balanced outputs whose bandpass characteristics are different. The vision carrier output has the sound carrier suppressed more than usual, resulting in fewer unwanted interference effects, e.g. sound-chroma beats. This is fed to a TELEFUNKEN TDA4427 i.c. which performs similar functions to the better known PHILIPS  TDA2540, i.e. vision if amplification and detection and a.f.c. detection. It differs from the TDA2540 in that it offers two video output signals of opposite polarity.
The sound carrier output from the SAWF is passed to a TDA4282 i.c. for processing. A block diagram is shown in Fig. 2. The i.c. has two basic sections.
The first is similar to a standard vision LE amplifier and detector. The i.f. amplifier incorporates a.g.c. control; the detector uses a standard LC tuned circuit and produces an output very similar to a standard composite video signal. This is brought out of the i.c. and the 6MHz sound i.f. signal is extracted by the usual 6MHz ceramic filter. This signal is fed back into the second section of the i.c. which com- prises an i.f. amplifier and detector, the latter using a ceramic discriminator and therefore not requiring any adjustment.
The recovered audio signal is routed through a "VCR" switching block inside the i.c. This enables either the off -air signal to pass to the output buffer amplifier or, by applying a switching voltage to the i.c., it blocks the off -air signal and allows an external audio signal to be connected to the buffer. In order to minimise the number of pins on the i.c. and to reduce the switching complexity, a single pin is used to provide an off -air audio output signal via the SCART socket to, say, a VCR in the record mode. When the switching voltage to the i.c. is applied, this same pin reverts to an input pin which will accept an external audio signal (e.g. from a VCR in the playback mode) and route it via the buffer stage to the TV set's audio amplifier. The audio output from the i.c. proceeds to a TDA4290 i.c. which provides d.c. operated control of volume, bass and treble. The output from this i.c. is fed to a TDA2008 a.f. amplifier and then to a speaker and earphone socket. In its standard form the chassis offers only mono reproduction: it's easy to convert for stereo by substituting the audio control/output section for one containing an additional TDA4290 and a twin a.f. amplifier i.c. Meanwhile, back at the composite video output from the TDA4427, this is passed through a 6MHz ceramic trap (again, no adjustment) to remove any residual intercamer sound signal present on the video signal and then, after some switching to enable video out/video in, the selected video signal is processed by a Motorola TDA3301 single -chip colour decoder. This is virtually identical to the TDA3300 which has been described in previous posts on  Obsolete Technology Tellye ! .
There is nothing particularly exceptional about the i.c. (except the extraordinary degree of integration) - it offers the usual RGB inputs with fast picture blanking, making an easy interface with the optional teletext decoder module.
 One nice feature of this i.c. is the facility of automatic black level control. It does this by monitoring beam current during flyback blanking.
The value of the beam current under these conditions should of course be zero (i.e. the tube be cut off or else you don't have blanking!). If the i.c. senses some beam current on any one of the three guns, then it adjusts the d.c. pedestal of the appropriate colour output until there is zero beam current.
Not only does this process result in "perfect" grey scale but it retains this throughout the life of the tube (as tubes age the black level for any of the three guns can change causing a deterioration of grey scale). It also compensates for component value changes in the video output stages due to age. The video output stages themselves are of the class AB type and, as is usual nowadays, mounted on thetube base board to avoid the extra capacitance offered by the RGB connecting cable required with mounting on the main p.c.b. An extra pnp transistor connected between each video output stage and the c.r.t. cathode senses the beam current and feeds the information back to the colour decoder i.c. as explained above.
Digital Control:
 So much then for the basic outline of the receiver. We now turn our attention to the digital sectionwhich contains the frequency synthesis tuning system. The SX9's control system is based on a Philips/Mullard development which offers: (1) user controls - either by remote plus local or local only; (2) tuning; (3) teletext acquisition and display (optional); and (4) signal processing control. It is a very versatile and sophisticated system, and the high degree of integration means that few peripheral components are needed. The system is illustrated in Fig. 3.
It is based on five i.c.s: PHILIPS MAB8440 microcomputer; PHILIPS SAA3004 remote control transmitter; TDA3048 infra -red preamplifier; PCD8571 CMOS memory; and PHILIPS SAB3035 tuning i.c.
Remote Control:
 The remote control transmitter is very straightforward. The keypad is the usual matrix type. The i.c. is capable of a maximum of 7 sets of 64 commandsalthough of course not all are used in the SX9.
 Instead of the usual expensive crystal, the PHILIPS SAA3004 uses a 455kHz ceramic resonator to produce its internal clock. In order to conserve battery power, the oscillator is not active until a button is depressed. In this standby condition the i.c. consumes a mere 2µA.
The output from the i.c. is amplified by a single transistor and the output from this is used to drive an i.r. diode. Very few peripheral components are used. The remote control commands are pulse -position coded, with modulated pulses. The spacing between the frequency bursts determines whether thesignal is a "0" or a "1". Frequency bursts allow the use of a narrow band receiver circuit which makes the system less sensitive to interference. A complete command consists of a reference bit, a toggle bit, 3 address bits and 6 bits for the command itself. Incidentally, if a command button is pressed for sufficiently long to enable the transmitter to start sending 130 the information, but happens to be released before the process is completed, the transmitter will ensure that the complete command is sent before returning to its standby mode. The reference bit is used by the receiver as a time reference - it is always a "1" and lasts for 7.59ms. The toggle bit changes state each time a new command is sent. The address bits are selected by the manufacturer to suit each application. Their selection determines which one out of the possible 7 sets of commands is to be used. In the SX9, the address bits are all "0". The six command bits are dependent on the command itself and of course allow one of 64 commands to be sent. At the receiver end, the TDA3048 infra -red receiver i.c. consists of a controlled r.f. amplifier, demodulator, a.g.c. generator, limiter, pulse shaper and output stage. A filter at the input of the i.c. limits the bandwidth of the applied signal, thus ensuring minimum interference. A "Q -killer" circuit automatically reduces the Q of the input tuned circuit in order to limit strong signals reaching the amplifier. This can happen if the transmitter is operated too close to the receiver, in which case the signal can exceed the a.g.c. range. Microcomputer Control System The heart of the system is the microcomputer. Most of its functions are already programmed, but the customer (TV manufacturer) has a number of options he can specify. It is therefore best described as a dedicated microcomputer (designed specifically for this sort of application) whose parameters can be altered by software control. Its tasks are to decode the remote control com- mands, offer local customer "front panel" control, generate data for a seven segment display, control the tuning i.c. and communicate with other devices connected to the serial bus (i.e. memory, text, etc.). The modulated pulse train from the infra -red receiver module is connected to the microcomputer where it is decoded. This function is performed by a block known as the control/timing block. It incorporates the microcomputer's on chip oscillator which runs at 4MHz. In order to store data when the set is switched off, a 1k memory powered by a rechargeable NiCad 1.2V battery is used. The PCD8571 is a 1024 bit CMOS memory organised as 128 x 8 bits. It is connected to the microcomputer via the serial bus. The memory stores channel number; frequency offset from "correct" channel frequency; TV standards (for use in multistandard sets); long/short time constant; on off satellite; on -off video; on - off a.f.c.; on -off NTSC; preferred teletext pages; seven personal preference adjustments (e.g. volume, brightness, etc.). The above render the memory virtually full. The memory is powered from the +5V rail via a diode when the set is switched on. At the same time, the battery is charged via a current limiting resistor. When the +5V collapses (i.e. when the set is switched off), the diode is reversed biased, therefore preventing the battery from being discharged by other circuitry connected to the +5V rail. The last i.c. in the system is the tuning i.c., type SAB3035. This provides synthesised tuning with a.f.c.; band switching; reception switching (e.g. satellite and VCR); analogue control of up to 8 functions. It receives its information from the microcomputer via the serial bus and has an internal reference clock running at 4MHz using an external crystal. The tuning voltage generator is fed from the stabilised +33V rail and a linear amplifier acts as a series pass element under the control of the information received on the bus, producing an output voltage from around 0.3V to +33V. The analogue controls each produce 64 voltage "step" levels from 0.5V to 10.5V and these are used to control volume, bass, treble, balance (when used), brightness, colour saturation, contrast, and loudness (the last function is used as a switching function to introduce a loudness contour on the frequency response). This is a function of the TDA4290 a.f. processor i.c. The digital control system briefly described is one with a considerable amount of built-in flexibility, thanks to its ability to be programmed. No doubt we shall see it being used elsewhere in a future in the 1980's.

Other points of interest on the SX9 chassis are an optional SECAM transcoder based on the Motorola TDA3030 i.c. which is used in conjunction with the TDA3331. The latter is also capable of NTSC operation and this can be catered for in the SX9 chassis. There is, of course, an optional teletext module, which is bases on the Philips/Mullard set of teletext i.c.s. The one difference is the use of the PHILIPS MAB8410 which is another in the microcomputer series. Its essential function is to transcode the bus information into the format required by the teletext i.c.s. Luxor offer the additional facility of either the transmitted teletext colours or their complements, achieved with the use of an XOR gate i.c. type 74LS136.
Another feature when in the teletext mode prevents the usual interlace flicker.
This is achieved by feedback from the field timebase to the sync generator circuit of the teletext decoder to effectively stop the interlace. It appears to be a feature which is becoming more !popular and is usually found on Prestel equipment as an option but is now finding favour amongst TV manufacturers. Another feature included on the SX9 is the SCART socket.
This is simply a socket which allows the TV set to be connected to external equipment. It was a standard agreed by a French committee and seems to have gained favour throughout Europe. SCART stands for Syndicat des Constructeurs d'Appareils Radio Recepteurs et Televiseurs. This is the name of the French originating committee and, even if your French is as non-existent as mine, translation is obvious. Philips have decided to call their SCART socket the "Euroconnector", which is per- haps a more easily remembered title, but the important thing is that it's identical. Yet another name for it is the PERI-connector (peripheral) but this is not much used.
 The connector on the TV set is a 21 pin socket, arranged in two rows with alternating pin numbering, starting on the left hand side of the longest row (see Fig. 4). Before giving the pin functions, it's worthwhile summarising some of the advantages. For a start, it can turn the set into a (fairly) good monitor, capable of accepting either a 1V pk-pk compos- ite colour video signal (multistandard if the set is so designed) or separate RGB plus composite sync.
The former can be used with VCRs, video cameras, most games consoles and some personal computers.
The latter, which produces even better results by bypassing the set's decoder, can be used with most personal computers and most small business computers (watch out though - a 14in. TV tube is not really capable of resolving a line of text with more than 40 characters. Most business machines use 80 characters, as do some programmes written for personal computers, such as word processing). It is also possible to connect the TV sound to external hi-fi equipment with considerable quality improvement. It also makes for simpler source switching if one is equipped with all the gadgets - computer, video disc, VCR etc.
 Other, less obvious and possibly with less potential, uses include monitoring and controlling home appliances (e.g. central heating) via the set; bilingual operation by using the left and right sound channels when stereo broadcasting arrives; cheaper teletext decoder addons by using the composite video output to feed the decoder and the RGB connector inputs to display the information. There are still one or two "loose" parameters which have not been finalised, although it is fairly certain that changes, if any, will be minor.
The pinning, then, is as follows: 1: Audio out - right 500mV/ 1 k 2: Audio in - right 500mV/ 1 k 3: Audio out - left 500mV/ 1 k 4: Audio earth 5: Blue earth 6: Audio in - left 500mV/1 k 7: Blue in 0-7V/7551 8: Source switching 0-2V/10-12V/10k 9: Green earth 10: Intercommunication line (data bus) 11: Green in 0.7V/75f1 12: Intercommunication line (data bus) 13: Red earth 14: Data bus earth 15: Red in 07V/7551 16: Status RGB (fast blanking) 0 -0 -4V/1 -3V 17: Composite video earth 18: RGB blanking earth 19: Composite video out 1 V/755/ 20: Composite video in 1V/75n 21: Socket earth Not all the pins need be used of course. Some ready made cables to suit particular applications are becoming available but are expensive. A much cheaper alternative is to make up your own, ensuring that you use 75.51 cable where indicated and that the impedances and levels of the peripheral equipment inputs/outputs


The SAB3035 provides closed-loop digital tuning of TV receivers, with or without a.f.c., as required. lt
also controls up to 8 analogue functions, 4 general purpose I/O ports and 4 high-current outputs for
tuner band selection.
The IC is used in conjunction with a microcomputer from the MAB8400 family and is controlled via a two-wire, bidirectional I2 C bus.
Featu res
Combined analogue and digital circuitry minimizes the number of additional interfacing components
Frequency measurement with resolution of 50 KHz
Selectable prescaler divisor of 64 or 256
32 V tuning voltage amplifier
4 high-current outputs for direct band selection
8 static digital to analogue converters (DACSI for control of analogue functions
Four general purpose input/output (l/O) ports
Tuning with control of speed and direction
Tuning with or without a.f.c.
Single-pin, 4 MHZ on-chip oscillator
I2 C bus slave transceiver

The SAB3035 is a monolithic computer interface which provides tuning and control functions and
operates in conjunction with a microcomputer via an I2 C bus.
This is performed using frequency-locked loop digital control. Data corresponding to the required tuner
frequency is stored in a 15-bit frequency buffer. The actual tuner frequency, divided by a factor of 256
(or by 64) by a prescaler, is applied via a gate to a 15-bit frequency counter. This input (FDIV) is
measured over a period controlled by a time reference counter and is compared with the contents of the frequency buffer. The result of the comparison is used to control the tuning voltage so that the tuner frequency equals the contents of the frequency buffer multiplied by 50 kHz within a programmable tuning window (TUW).

The system cycles over a period of 6,4 ms (or 2,56 ms), controlled by the time reference counter which is clocked by an on-chip 4 lVlHz reference oscillator. Regulation of the tuning voltage is performed by a charge pump frequency-locked loop system. The charge IT flowing into the tuning voltage amplifier is controlled by the tuning counter, 3-bit DAC and the charge pump circuit. The charge IT is linear with the frequency deviation Af in steps of 50 l.


The TDA2594 is a monolithic integrated circuit intended for use in colour television receivers.
The circuit incorporates the following functions:
0 Horizontal oscillator based on the threshold switching principle.
0 Phase comparison between sync pulse and oscillator voltage (tp1).
0 Internal key pulse for phase detector (-D) fYP~ ‘I V
V3-1elp-pl WP- 1° V

* Permissible range: 1 t



The TDA1670A is a monolithic integrated circuit in
15-lead Multiwatt® package. It is a full performance
and very efficient vertical deflection circuit intended
for direct drive of the yoke of 110o colour TV picture
tubes. It offers a wide range of applications also in
portable CTVs, B&W TVs, monitors and displays.


Oscillator and sync gate (Clock generation)
The oscillator is obtained by means of an integrator
driven by a two threshold circuit that switches Ro
high or low so allowing the charge or the discharge
of Co under constant current conditions.
The Sync input pulse at the Sync gate lowers the
level of the upper threshold and than it controls the
period duration. A clock pulse is generated.
Pin 4 is the inverting input of the amplifier used
as integrator.
Pin 6 is the output of the switch driven by the
internal clock pulse generated by the
threshold circuits.
Pin 3 is the output of the amplifier.
Pin 5 is the input for sync pulses (positive)
Ramp generator and buffer stage
A current mirror, the current intensity of which can
be externally adjusted, charges one capacitor
producing a linear voltage ramp.
The internal clock pulse stops the increasing ramp
by a very fast discharge of the capacitor a new
voltage ramp is immediately allowed.

The required value of the capacitance is obtained
by means of the series of two capacitors Ca and
Cb, which allow the linearity control by applying a
feedback between the output of the buffer and the
tapping from Ca and Cb.
Pin 7 The resistance between pin 7 and ground
defines the current mirror current and
than the height of the scanning.
Pin 9 is the output of the current mirror that
charges the series of Ca and Cb. This
pin is also the input of the buffer stage.
Pin 10 is the output of the buffer stage and it is
internally coupled to the inverting input
of the power amplifier through R1.
Power amplifier
This amplifier is a voltage-to-current power
converter, the transconductance of which is
externally defined by means of a negative current
The output stage of the power amplifier is supplied
by the main supply during the trace period, and by
the flyback generator circuit during the most of the
duration of the flyback time. The internal clock turns
off the lower power output stage to start the flyback.
The power output stage is thermally protected by
sensing the junction temperature and then by
putting off the current sources of the power stage.
Pin 12 is the inverting input of the amplifier.
An external network, Ra and Rb, defines
the DClevel across Cy so allowing a correct
centering of the output voltage. The
series network Rc and Cc, in conjunction
with Ra and Rb, applies at the feedback
input I2 a small part of the parabola,
available across Cy, and AC feedback
voltage, taken across Rf. The external
components Rc, Ra and Rd, produce the
linearity correction on the output scanning
currentIy and their values must be
optimized for each type of CRT.
Pin 11 is the non-inverting input. At this pin the
non-inverting input reference voltage
supplied by the voltage regulator can be
measured. A capacitor must be connected
to increase the performances
from the noise point of view.
Pin 1 is the output of the power amplifier and it
drives the yoke by a negative slope current
ramply. Re and the Boucherot cell
are used to stabilize the power amplifier.
Pin 2 The supply of the power output stage is
forced at this pin. During the trace time
the supply voltage is obtained from the
main supply voltage VS by a diode,
while during the retrace time this pin is
supplied from the flyback generator.
Flyback generator
This circuit supplies both the power amplifier output
stage and the yoke during the most of the duration
of the flyback time (retrace).
The internal clock opens the loop of the amplifier
and lets pin 1 floating so allowing the rising of the
flyback. Crossing the main supply voltage at pin 14,
the flyback pulse front end drives the flyback
generator in such a way allowing its output to reach
and overcome the main supply voltage, starting
from a low condition forced during the trace period.
An integrated diode stops the rising of this output
increase and the voltage jump is transferred by
means of capacitor Cf at the supply voltage pin of
the power stage (pin 2).
When the current across the yoke changes its
direction, the output of the flyback generator falls
down to the main supply voltage and it is stopped
by means of the saturated output darlington at a
high level. At this time the flyback generator starts
to supply the power output amplifier output stage
by a diode inside the device. The flyback generator
supplies the yoke too.
Later, the increasing flyback current reaches the
peak value and then the flyback time is completed:
the trace period restarts. The output of the power
amplifier (pin 1) falls under the main supply voltage
and the output of the flyback generator is driven for
a low state so allowing the flyback capacitor Cf to
restore the energy lost during the retrace.
Pin 15 is the output of the flyback generator that,
when driven, jumps from low to high
condition. An external capacitor Cf transfers
the jump to pin 2 (see pin 2).
Blanking generator and CRT protection
This circuit is a pulse shaper and its output goes
high during the blanking period or for CRT
protection. The input is internally driven by the clock
pulse that defines the width of the blanking time

when a flyback pulse has been generated. If the
flyback pulse is absent (short cirucit or open cirucit
of the yoke), the blanking output remains high so
allowing the CRT protection.
Pin 13 is an open collector output where the
blanking pulse is available.
Voltage regulator
The main supply voltage VS, is lowered and
regulated internally to allow the required reference
voltages for all the above described blocks.
Pin 14 is the main supply voltage input VS
Pin 8 is the GND pin or the negative input of VS.

The power dissipated in the circuit must be
removed by adding an external heatsink. Thanks
to the MULTIWATT ® package attaching the
heatsink is very simple, a screw or a compression
spring (clip) being sufficient. Between the heatsink
and the package, it is better to insert a layer of
silicon grease, to optimize the thermal contact; no
electrical isolation is needed between the two


The Decoder IC The centre -piece of the decoder is the Motorola TDA3300B i.c. which carries out all the luminance and U V Inputs from PAL delay line 9V Frequency nlyv Z 2RV2 100k chroma signal processing required. Features of this 40 -pin chip include: (1) Automatic black -current control via feedback from the RGB output circuits. (2) Peak beam current limiting to prevent blooming on highlights - in addition to the normal beam current limit- ing action. (3) Separate R, G and B input pins for the injection of teletext/data signals (or on -screen display of the channel number with frequency synthesis tuning). These signals can be varied by means of the user brightness and con- trast controls. (4) Low dissipation - about 600mW. (5) By adding a small adaptor panel with a TDA3030A SECAM-to-PAL converter i.c. during production the receiver is given multistandard (PAL, SECAM and NTSC-4.43) capability.

A block diagram of the TDA3300B i.c. is shown in Fig. 3. As with the better known TDA3560 single -chip decoder, both the chroma and the burst pass through the chroma delay line. The U output from this enters the TDA3300B at pin 8, passing to the U detector and to the burst detector. The latter is part of a phase -locked loop, the detector's output being applied via an H/2 (half-line frequency) switch to the 4.43MHz voltage -controlled crystal oscillator. The 4.43MHz reference oscillator's output is applied for PAL switching, and to the U detector via a voltage -controlled 90° phase shifter. This shifter is under the control of the 90° detec- tor which compares its output with the oscillator's output coming via the PAL switch: when the phase shift is cor- rect, the output from the 90° phase detector is zero. The combined effect of the two H/2 switches in the reference oscillator control loop - the two shown on the right-hand side - cancels phase detector offsets. The outputs from the U and V detectors include burst "flag" pulses which are used for a.c.c., ident and colour -killing - there are two colour -killing actions. RGB Output Stages The RGB output stages are of the class AB type and incorporate extra circuitry for c.r.t. black -current sampl- ing and beam limiting. Fig. 4 shows the red output stage. Under most conditions transistor 2TR1 acts as a class A amplifier, driving the tube's cathode via 2D5 and 2TR7. A high -value collector load resistor (2R33) is used to reduce the dissipation in 2TR1. The stage gain is set by the ratio of 2R40 and 2R36 to 2R25 and 2RV3, the latter setting the drive level. For good transient response it's necessary for the tube/base capacitance to be rapidly charged/discharged in accordance with the signal swings. There is no problem when 2TR1 is being driven from off to on, since the capacitance is discharged rapidly via 2D5 and 2TR1. When 2TR1 is driven from on to off however 2D5 will become reverse biased. Under these conditions 2TR4 acts as an emitter -follower so that the capacitance charges rapidly. Black -level stability is critical for good results. As we've 2R46 5k6 2R51 120k 2TR7 BF493S 2C43l Sampling circuit L -J 1k5 Field blanking J Red cathode _Tube input T"and base 810capacitance nlrr Reference Line pedestal blanking Sample -and - hold amplifier-ws switched on rt- Video Urn seen, the TDA3300B chip incorporates circuitry for automatic black -current correction. Making use of this reduces service calls and ensures constant performance despite tube ageing or circuit misadjustment. Feedback is required, and this is provided by the sampling circuit shown in the box with the broken outline. Transistor 2TR7 acts as an emitter -follower between the video output stage and the c.r.t.'s cathode. It's a low leakage type, the components 2C40, 2D10 and 2C43 ensuring that the circuit has negligible effect on the video signal. Since the beam current flows via 2R51, a voltage proportional to the beam current is produced across this resistor. It's fed into the TDA3300B at pin 22. Black -current Control For automatic black -current control the important thing is the small beam current that flows when the tube is biased just above cut off. To enable this current to be sampled, the TDA3300B replaces the video signal with a fixed reference pedestal voltage for a couple of lines at the end of each field blanking period (this pedestal can be seen as a grey line at the top of the picture if the height control's setting is reduced). The sample voltage at pin 22 of the i.c. is fed to one input of a sample -and -hold amp- lifier which is switched on to sample the input for one line only of the reference pedestal period. 2C33 acts as the black -current control reservoir capacitor, holding the charge acquired during the sampling time for the whole field period. This charge is added to the video signal within the i.c., thus maintaining the correct red gun black current. It's interesting to notice that when a set is switched on from cold there's a momentary screen bright -up with flyback lines as the beam current begins to flow. This is because it takes several fields for 2C33 (and the corre- sponding capacitors in the green and blue channels) to charge fully. Since the voltage continuously available across 2R51 is proportional to beam current, it's used within the i.c. for peak beam current limiting during the active line periods. This is in addition to beam current limiting via the con- trast control - and a crowbar trip that operates should the beam current exceed 3mA.
This device will accept a PAL or NTSC composite video signal and output the
three color signals, needing only a simple driver amplifier to interface to the pic-
ture tube. The provision of high bandwidth on-screen display inputs makes it
suitable for text display, TV games, cameras, etc. The TDA3301 B has user con»
trol laws, and also a phase shift control which operates in PAL, as well as NTSC.
0 Automatic Black Level Setup
0 Beam Current Limiting
0 Uses Inexpensive 4.43 MHZ to 3.58 MHz Crystal
0 No Oscillator Adjustment Required
0 Three OSD Inputs Plus Fast Blanking Input
0 Four DC, High Impedance User Controls
0 lnterlaces with TDA33030B SECAM Adaptor
0 Single 12 V Supply
0 Low Dissipation, Typically 600 mW
The brilliance control operates by adding a pedestal to the output
signals. The amplitude of the pedestal is controlled by Pin 30.
During CRT beam current sampling a standard pedestal is
substituted, its value being equivalent tothe value given by V30 Nom
Brightness at black level with V30 Nom is given by the sum of three gun
currents at the sampling level, i.e. 3x20 |.1A with 100 k reference
resistors on Pins 16, 19, and 22.
During picture blanking the brilliance pedestal is zero; therefore, the
output voltage during blanking is always the minimum brilliance black
level (Note: Signal channels are also gain blanked).

Chrominance Decoder
The chrominance decoder section of the TDA3301 B
consists of the following blocks:
Phase-locked reference oscillator;
Phase-locked 90 degree servo loop;
U and V axis decoders
ACC detector and identification detector; .
Identification circuits and PAL bistable; .
Color difference filters and matrixes with fast blanking
The major design considerations apart from optimum
performance were:
o A minimum number of factory adjustments,
o A minimum number of external components,
0 Compatibility with SECAM adapter TDA3030B,
0 Low dissipation,
0 Use of a standard 4.433618 Mhz crystal rather
than a 2.0 fc crystal with a divider.

The crystal VCO is of the phase shift variety in which the
frequency is controlled by varying the phase of the feedback.
A great deal of care was taken to ensure that the oscillator loop
gain and the crystal loading impedance were held constant in
order to ensure that the circuit functions well with low grade
crystal (crystals having high magnitude spurious responses
can cause bad phase jitter). lt is also necessary to ensure that
the gain at third harmonic is low enough to ensure absence of
oscillation at this frequency.

It can be seen that the
necessary 1 45°C phase shift is obtained by variable addition
ol two currents I1 and I2 which are then fed into the load
resistance of the crystal tuned circuit R1. Feedback is taken
from the crystal load capacitance which gives a voltage of VF
lagging the crystal current by 90°.
The RC network in the T1 collector causes I1 to lag the
collector current of T1 by 45°.
For SECAM operation, the currents I1 and I2 are added
together in a fixed ratio giving a frequency close to nominal.
When decoding PAL there are two departures from normal
chroma reference regeneration practice:
a) The loop is locked to the burst entering from the PAL
delay line matrix U channel and hence there is no
alternating component. A small improvement in signal
noise ratio is gained but more important is that the loop
filter is not compromised by the 7.8 kHz component
normally required at this point for PAL identification
b) The H/2 switching of the oscillator phase is carried out
before the phase detector. This implies any error signal
from the phase detector is a signal at 7.8 kHz and not dc.
A commutator at the phase detector output also driven
from the PAL bistable coverts this ac signal to a dc prior
to the loop filter. The purpose ot this is that constant
offsets in the phase detector are converted by the
commutator to a signal at 7.8 kHz which is integrated to
zero and does not give a phase error.
When used for decoding NTSC the bistable is inhibited, and
slightly less accurate phasing is achieved; however, as a hue
control is used on NTSC this cannot be considered to be a
serious disadvantage.

90° Reference Generation
To generate the U axis reference a variable all-pass network
is utilized in a servo loop. The output of the all-pass network
is compared with the oscillator output with a phase detector of
which the output is filtered and corrects the operating point of
the variable all»pass network .
As with the reference loop the oscillator signal is taken after
the H/2 phase switch and a commutator inserted before the
filter so that constant phase detector errors are cancelled.
For SECAM operation the loop filter is grounded causing
near zero phase shift so that the two synchronous detectors
work in phase and not in quadralure.
The use of a 4.4 MHz oscillator and a servo loop to generate
the required 90° reference signal allows the use of a standard,
high volume, low cost crystal and gives an extremely accurate
90° which may be easily switched to 0° for decoding AM
SECAM generated by the TDA3030B adapter.

ACC and Identification Detectors
During burst gate time the output components of the U and
also the V demodulators are steered into PNP emitters. One
collector current of each PNP pair is mirrored and balanced
against its twin giving push-pull current sources for driving the
ACC and the identification filter capacitors.
The identification detector is given an internal offset by
making the NPN current mirror emitter resistors unequal. The
resistors are offset by 5% such that the identification detector
pulls up on its filter capacitor with zero signal.
See Figure 11 for definitions.
Monochrome I1 > I2
PAL ldent. OK I1 < lg
PAL ldent_ X l1 > I2
NTSC I3 > I2
Only for correctly identified PAL signal is the capacitor
voltage held low since I2 is then greater than I1.
For monochrome and incorrectly identified PAL signals l1>l2
hence voltage VC rises with each burst gate pulse.
When V,ef1 is exceeded by 0.7 V Latch 1 is made to conduct
which increases the rate of voltage rise on C. Maximum
current is limited by R1.
When Vref2 is exceeded by 0.7 V then Latch 2 is made to
conduct until C is completely discharged and the current drops
to a value insufficient to hold on Latch 2.
As Latch 2 turns on Latch 1 must turn off.
Latch 2 turning on gives extra trigger pulse to bistable to
correct identification.
The inhibit line on Latch 2 restricts its conduction to alternate
lines as controlled by the bistable. This function allows the
SECAM switching line to inhibit the bistable operation by firing
Latch 2 in the correct phase for SECAM. For NTSC, Latch 2
is fired by a current injected on Pin 6.
lf the voltage on C is greater than 1.4 V, then the saturation
is held down. Only for SECAM/NTSC with Latch 2 on, or
correctly identified PAL, can the saturation control be
anywhere but minimum.
NTSC Switch
NTSC operation is selected when current (I3) is injected into
Pin 6. On the TDA33O1 B this current must be derived
externally by connecting Pin 6 to +12 V via a 27 k resistor (as
on TDA33OOB). For normal PAL operation Pin 40 should be
connected to +12 V and Pin 6 to the filter capacitor.

4 Color Difference Matrixing, Color Killing,
and Chroma Blanking
During picture time the two demodulators feed simple RC
filters with emitter follower outputs. Color killing and blanking
is performed by lifting these outputs to a voltage above the
maximum value that the color difference signal could supply.
The color difference matrixing is performed by two
differential amplifiers, each with one side split to give the
correct values of the -(B-Y) and -(Ft-Y) signals. These are
added to give the (G-Y) signal.
The three color difference signals are then taken to the
virtual grounds of the video output stages together with
luminance signal.
Sandcastle Selection
The TDA3301B may be used with a two level sandcastle
and a separate frame pulse to Pin 28, or with only a three level
(super) sandcastle. In the latter case, a resistor of 1.0 MQ is
necessary from + 12 V to Pin 28 and a 70 pF capacitor from
Pin 28 to ground.

Timing Counter for Sample Control
In order to control beam current sampling at the beginning
of each frame scan, two edge triggered flip-flops are used.
The output K ofthe first flip-flop A is used to clock the second
tlip-flop B. Clocking of A by the burst gate is inhibited by a count
of A.B.
The count sequence can only be initiated by the trailing
edge of the frame pulse. ln order to provide control signals for:
Luma/Chroma blanking
Beam current sampling
On-screen display blanking
Brilliance control
The appropriate flip-flop outputs ar matrixed with sandcastle
and frame signals by an emitter-follower matrix.

Video Output Sections
Each video output stage consists of a feedback amplifier in A further drive current is used to control the DC operating
which the input signal is a current drive to the virtual earth from point; this is derived from the sample and hold stage which
the luminance, color difference and on-screen display stages. samples the beam current after frame flyback.

SMPS POWER Supply is based on TDA4600 (SIEMENS).
LUXOR  5134  TYPE 18051341  CHASSIS  B3-1 (SX9) Power supply Description based on TDA4601d (SIEMENS)

TDA4601 Operation. * The TDA4601 device is a single in line, 9 pin chip. Its predecessor was the TDA4600 device, the TDA4601 however has improved switching, better protection and cooler running. The (SIEMENS) TDA4601 power supply is a fairly standard parallel chopper switch mode type, which operates on the same basic principle as a line output stage. It is turned on and off by a square wave drive pulse, when switched on energy is stored in the chopper transformer primary winding in the form of a magnetic flux; when the chopper is turned off the magnetic flux collapses, causing a large back emf to be produced. At the secondary side of the chopper transformer this is rectified and smoothed for H.T. supply purposes. The advantage of this type of supply is that the high chopping frequency (20 to 70 KHz according to load) allows the use of relatively small H.T. smoothing capacitors making smoothing easier. Also should the chopper device go short circuit there is no H.T. output. In order to start up the TDA4601 I.C. an initial supply of 9v is required at pin 9, this voltage is sourced via R818 and D805 from the AC side of the bridge rectifier D801, also pin 5 requires a +Ve bias for the internal logic block. (On some sets pin 5 is used for standby switching). Once the power supply is up and running, the voltage on pin 9 is increased to 16v and maintained at this level by D807 and C820 acting as a half wave rectifier and smoothing circuit. PIN DESCRIPTIONS Pin 1 This is a 4v reference produced within the I.C. Pin 2 This pin detects the exact point at which energy stored in the chopper transformer collapses to zero via R824 and R825, and allows Q1 to deliver drive volts to the chopper transistor. It also opens the switch at pin 4 allowing the external capacitor C813 to charge from its external feed resistor R810. Pin 3 H.T. control/feedback via photo coupler D830. The voltage at this pin controls the on time of the chopper transistor and hence the output voltage. Normally it runs at Approximately 2v and regulates H.T. by sensing a proportion of the +4v reference at pin 1, offset by conduction of the photo coupler D830 which acts like a variable resistor. An increase in the conduction of transistor D830 and therefor a reduction of its resistance will cause a corresponding reduction of the positive voltage at Pin 3. A decrease in this voltage will result in a shorter on time for the chopper transistor and therefor a lowering of the output voltage and vice versa, oscillation frequency also varies according to load, the higher the load the lower the frequency etc. should the voltage at pin 3 exceed 2.3v an internal flip flop is triggered causing the chopper drive mark space ratio to extend to 244 (off time) to 1 (on time), the chip is now in over volts trip condition. Pin 4 At this pin a sawtooth waveform is generated which simulates chopper current, it is produced by a time constant network R810 and C813. C813 charges when the chopper is on and is discharged when the chopper is off, by an internal switch strapping pin 4 to the internal +2v reference, see Fig 2. The amplitude of the ramp is proportional to chopper drive. In an overload condition it reaches 4v amplitude at which point chopper drive is reduced to a mark-space ratio of 13 to 1, the chip is then in over current trip. The I.C. can easily withstand a short circuit on the H.T. rail and in such a case the power supply simply squegs quietly. Pin 4 is protected by internal protection components which limit the maximum voltage at this pin to 6.5v. Should a fault occur in either of the time constant components, then the chopper transistor will probably be destroyed. Pin 5 This pin can be used for remote control on/off switching of the power supply, it is normally held at about +7v and will cause the chip to enter standby mode if it falls below 2v. Pin 6 Ground. Pin 7 Chopper switch off pin. This pin clamps the chopper drive voltage to 1.6v in order to switch off the chopper. Pin 8 Chopper base current output drive pin. Pin 9 L.T. pin, approximately 9v under start-up conditions and 16v during normal running, Current consumption of the I.C. is typically 135mA. The voltage at this pin must reach 6.7v in order for the chip to start-up.

Semiconductor circuit for supplying power to electrical equipment, comprising a transformer having a primary winding connected, via a parallel connection of a collector-emitter path of a transistor with a first capacitor, to both outputs of a rectifier circuit supplied, in turn, by a line a-c voltage; said transistor having a base controlled via a second capacitor by an output of a control circuit acted upon, in turn by the rectified a-c line voltage as actual value and by a reference voltage; said transformer having a first secondary winding to which the electrical equipment to be supplied is connected; said transformer having a second secondary winding with one terminal thereof connected to the emitter of said transistor and the other terminal thereof connected to an anode of a first diode leading to said control circuit; said transformer having a third secondary winding with one terminal thereof connected, on the one hand, via a series connection of a third capacitor with a first resistance, to the other terminal of said third secondary winding and connected, on the other hand, to the emitter of said transistor, the collector of which is connected to said primary winding; a point between said third capacitor and said first resistance being connected to the cathode of a second diode; said control circuit having nine terminals including a first terminal delivering a reference voltage and connected, via a voltage divider formed of a third and fourth series-connected resistances, to the anode of said second diode; a second terminal of said control circuit serving for zero-crossing identification being connected via a fifth resistance to said cathode of said second diode; a third terminal of said control-circuit serving as actual value input being directly connected to a divider point of said voltage divider forming said connection of said first terminal of said control circuit to said anode of said second diode; a fourth terminal of said control circuit delivering a sawtooth voltage being connected via a sixth resistance to a terminal of said primary winding of said transformer facing away from said transistor; a fifth terminal of said control circuit serving as a protective input being connected, via a seventh resistance to the cathode of said first diode and, through the intermediary of said seventh resistance and an eighth resistance, to the cathode of a third diode having an anode connected to an input of said rectifier circuit; a sixth terminal of said control circuit carrying said reference potential and being connected via a fourth capacitor to said fourth terminal of said control circuit and via a fifth capacitor to the anode of said second diode; a seventh terminal of said control circuit establishing a potential for pulses controlling said transistor being connected directly and an eighth terminal of said control circuit effecting pulse control of the base of said transistor being connected through the intermediary of a ninth resistance to said first capacitor leading to the base of said transistor; and a ninth terminal of said control circuit serving as a power supply input of said control circuit being connected both to the cathode of said first diode as well as via the intermediary of a sixth capacitor to a terminal of said second secondary winding as well as to a terminal of said third secondary winding.

The invention relates to a blocking oscillator type switching power supply for supplying power to electrical equipment, wherein the primary winding of a transformer, in series with the emitter-collector path of a first bipolar transistor, is connected to a d-c voltage obtained by rectification of a line a-c voltage fed-in via two external supply terminals, and a secondary winding of the transformer is provided for supplying power to the electrical equipment, wherein, furthermore, the first bipolar transistor has a base controlled by the output of a control circuit which is acted upon in turn by the rectified a-c line voltage as actual value and by a set-point transmitter, and wherein a starting circuit for further control of the base of the first bipolar transistor is provided.
Such a blocking oscillator switching power supply is described in the German periodical, "Funkschau" (1975) No. 5, pages 40 to 44. It is well known that the purpose of such a circuit is to supply electronic equipment, for example, a television set, with stabilized and controlled supply voltages. Essential for such switching power supply is a power switching transistor i.e. a bipolar transistor with high switching speed and high reverse voltage. This transistor therefore constitutes an important component of the control element of the control circuit. Furthermore, a high operating frequency and a transformer intended for a high operating frequency are provided, because generally, a thorough separation of the equipment to be supplied from the supply naturally is desired. Such switching power supplies may be constructed either for synchronized or externally controlled operation or for non-synchronized or free-running operation. A blocking converter is understood to be a switching power supply in which power is delivered to the equipment to be supplied only if the switching transistor establishing the connection between the primary coil of the transformer and the rectified a-c voltage is cut off. The power delivered by the line rectifier to the primary coil of the transformer while the switching transistor is open, is interim-stored in the transformer and then delivered to the consumer on the secondary side of the transformer with the switching transistor cut off.
In the blocking converter described in the aforementioned reference in the literature, "Funkschau" (1975), No. 5, Pages 40 to 44, the power switching transistor is connected in the manner defined in the introduction to this application. In addition, a so-called starting circuit is provided. Because several diodes are generally provided in the overall circuit of a blocking oscillator according to the definition provided in the introduction hereto, it is necessary, in order not to damage these diodes, that due to the collector peak current in the case of a short circuit, no excessive stress of these diodes and possibly existing further sensitive circuit parts can occur.
Considering the operation of a blocking oscillator, this means that, in the event of a short circuit, the number of collector current pulses per unit time must be reduced. For this purpose, a control and regulating circuit is provided. Simultaneously, a starting circuit must bring the blocking converter back to normal operation when the equipment is switched on, and after disturbances, for example, in the event of a short circuit. The starting circuit shown in the literature reference "Funkschau" on Page 42 thereof, differs to some extent already from the conventional d-c starting circuits. It is commonly known for all heretofore known blocking oscillator circuits, however, that a thyristor or an equivalent circuit replacing the thyristor is essential for the operation of the control circuit.
It is accordingly an object of the invention to provide another starting circuit. It is a further object of the invention to provide a possible circuit for the control circuit which is particularly well suited for this purpose. It is yet another object of the invention to provide such a power supply which is assured of operation over the entire range of line voltages from 90 to 270 V a-c, while the secondary voltages and secondary load variations between no-load and short circuit are largely constant.
With the foregoing and other objects in view, there is provided, in accordance with the invention, a blocking oscillator-type switching power supply for supplying power to electrical equipment wherein a primary winding of a transformer, in series with an emitter-collector path of a first bipolar transistor, is connected to a d-c voltage obtained by rectification of a line a-c voltage fed-in via two external supply terminals, a secondary winding of the transformer being connectible to the electrical equipment for supplying power thereto, the first bipolar transistor having a base controlled by the output of a control circuit acted upon, in turn, by the rectified a-c line voltage as actual value and by a set-point transmitter, and including a starting circuit for further control of the base of the first bipolar transistor, including a first diode in the starting circuit having an anode directly connected to one of the supply terminals supplied by the a-c line voltage and a cathode connected via a resistor to an input serving to supply power to the control circuit, the input being directly connected to a cathode of a second diode, the second diode having an anode connected to one terminal of another secondary winding of the transformer, the other secondary winding having another terminal connected to the emitter of the first bipolar transmitter.
In accordance with another feature of the invention, there is provided a second bipolar transistor having the same conduction type as that of the first bipolar transistor and connected in the starting circuit with the base thereof connected to a cathode of a semiconductor diode, the semiconductor diode having an anode connected to the emitter of the first bipolar transistor, the second bipolar transistor having a collector connected via a resistor to a cathode of the first diode in the starting circuit, and having an emitter connected to the input serving to supply power to the control circuit and also connected to the cathode of the second diode which is connected to the other secondary winding of the transformer.
In accordance with a further feature of the invention, the base of the second bipolar transistor is connected to a resistor and via the latter to one pole of a first capacitor, the anode of the first diode being connected to the other pole of the first capacitor.
In accordance with an added feature of the invention, the input serving to supply power to the control circuit is connected via a second capacitor to an output of a line rectifier, the output of the line rectifier being directly connected to the emitter of the first bipolar transistor.
In accordance with an additional feature of the invention, the other secondary winding is connected at one end to the emitter of the first bipolar transistor and to a pole of a third capacitor, the third capacitor having another pole connected, on the one hand, via a resistor, to the other end of the other secondary winding and, on the other hand, to a cathode of a third diode, the third diode having an anode connected via a potentiometer to an actual value input of the control circuit and, via a fourth capacitor, to the emitter of the first bipolar transistor.
In accordance with yet another feature of the invention, the control circuit has a control output connected via a fifth capacitor to the base of the first bipolar transistor for conducting to the latter control pulses generated in the control circuit.
In accordance with a concomitant feature of the invention, there is provided a sixth capacitor shunting the emitter-collector path of the first transistor.
Other features which are considered as characteristic for the invention are set forth in the appended claim.
Although the invention is illustrated and described herein as embodied in a blocking oscillator type switching power supply, it is nevertheless not intended to be limited to the details shown, since various modifications and structural changes may be made therein without departing from the spirit of the invention and within the scope and range of equivalents of the claims.

 A flyback transformer (FBT), also called a line output transformer (LOPT), is a special transformer, which is used for conversion of energy (current and voltage) in electronic circuits. It was initially designed to generate high current sawtooth signals at a relatively high frequency. In modern applications is used extensively in switched-mode power supplies for both low (3V) and high voltage (over 10 kV) supplies.
Flyback Transformer

It was invented as a means to control the horizontal movement of the electron beam in a cathode ray tube (CRT). Unlike conventional transformers, a flyback transformer is not fed with a signal of the same waveshape
as the intended output current. A convenient side effect of such a transformer is the considerable energy that is available in its magnetic circuit. This can be exploited using extra windings that can be used to provide power to operate other parts of the equipment. In particular, very high voltages are easily obtained using relatively few turns of winding which, once rectified, can provide the very high accelerating voltage for a CRT. Many more recent applications of such a transformer dispense with the need to produce high currents and just use the device as a relatively efficient means of producing a wide range of lower voltages using a transformer much smaller than a conventional mains transformer would be. 

Testing Flyback Transformer:

Nowadays, more and more monitor comes in with flyback transformers problems.
Testing flyback transformer are not difficult if you carefully follow the
instruction. In many cases, the flyback transformer can become short
circuit after using not more than 2 years. This is partly due to bad design
and low quality materials used during manufactures flyback transformer.
The question is what kind of problems can be found in a flyback transformer
and how to test and when to replace it. Here is an explanation that will help
you to identify many flyback transformer problems.
There are nine common problems can be found in a flyback transformer.
a) A shorted turned in the primary winding.
b) An open or shorted internal capacitor in secondary section.
c) Flyback Transformer becomes bulged or cracked.
d) External arcing to ground.
e) Internal arcing between windings.
f) Shorted internal high voltage diode in secondary winding.
g) Breakdown in focus / screen voltage divider causing blur display.
h) Flyback Transformer breakdown at full operating voltage (breakdown when under load).
i) Short circuit between primary and secondary winding.

Testing flyback transformer will be base on (a) and (b) since problem
(c) is visible while problem (d) and (e) can be detected by hearing the arcing
sound generated by the flyback transformer. Problem (f) can be checked with multimeter
set to the highest range measured from anode to ABL pin while (g) can be solved by
adding a new monitor blur buster (For 14' & 15' monitor only.) Problem (h) can only be
tested by substituting a known good similar Flyback Transformer. Different monitor have
different type of flyback transformer design. Problem (i) can be checked using an
ohm meter measuring between primary and secondary winding. A shorted turned or open
in secondary winding is very uncommon.

What type of symptoms will appear if there is a shorted turned in primary winding?
a) No display (No high voltage).
b) Power blink.
c) B+ voltage drop.
d) Horizontal output transistor will get very hot and later become shorted.
e) Along B+ line components will spoilt. Example:- secondary diode UF5404 and B+ FET IRF630.
f) Sometimes it will cause the power section to blow.

What type of symptoms will appear if a capacitor is open or shorted in a flyback transformer?

Capacitor shorted

a. No display (No high voltage).
b. B+ voltage drop.
c. Secondary diode (UF5404) will burned or shorted.
d. Horizontal output transistor will get shorted.
e. Power blink.
f. Sometimes power section will blow, for example: Raffles 15 inch monitor.
g. Power section shut down for example: Compaq V55, Samtron 4bi monitor.
h. Sometimes the automatic brightness limiter (ABL) circuitry components will get burned.
This circuit is usually located beside the flyback transformer. For example: LG520si

Capacitor open

a. High voltage shut down.
b. Monitor will have ‘tic - tic’ sound. Sometimes the capacitor may measure O.K. but
break down when under full operating voltage.
c. Horizontal output transistor will blow in a few hours or days after you have replaced it.
d. Sometimes it will cause intermittent "no display".
e. Distorted display i.e., the display will go in and out.
f. It will cause horizontal output transistor to become shorted and blow the power section.

How to check if a primary winding is good or bad in a Flyback Transformer?
a) By using a flyback/LOPT tester, this instrument identifies faults in primary winding by
doing a ‘ring’ test.
b) It can test the winding even with only one shorted turned.
c) This meter is handy and easy to use.
d) Just simply connect the probe to primary winding.
e) The readout is a clear ‘bar graph’ display which show you if the flyback transformer
primary winding is good or shorted.
f) The LOPT Tester also can be used to check the CRT YOKE coil, B+ coil and switch mode power transformer winding.

NOTE: Measuring the resistance winding of a flyback transformer, yoke coil, B+ coil and
SMPS winding using a multimeter can MISLEAD a technician into believing that a shorted
winding is good. This can waste his precious time and time is money.

How to diagnose if the internal capacitor is open or shorted?
By using a normal analog multimeter and a digital capacitance meter. A good capacitor have the range from 1.5 nanofarad to 3 nanofarad.*
1) First set your multimeter to X10K range.
2) Place your probe to anode and cold ground.
3) You must remove the anode cap in order to get a precise reading.
4) Cold ground means the monitor chassis ground.
5) If the needle of the multimeter shows a low ohms reading, this mean the internal capacitor
is shorted.
6) If the needle does not move at all, this doesn’t mean that the capacitor is O.K.
7) You have to confirm this by using a digital capacitance meter which you can easily get one
from local distributor.
8) If the reading from the digital capacitance meter shows 2.7nf, this mean the capacitor is
within range (O.K.).
9) And if the reading showed 0.3nf, this mean the capacitor is open.
10) You have three options if the capacitor is open or shorted.
- Install a new flyback transformer or
- Send the flyback transformer for refurbishing or
- Send the monitor back to customers after spending many hours and much effort on it.

* However certain monitors may have the value of 4.5nf, 6nf and 7.2nf.
Note: Sometimes the internal capacitor pin is connected to circuits (feedback) instead of ground.
Tv rca flyback transformer circuits usually do not have a internal capacitor in it.
If you have a flyback diagram and circuits which you can get it from the net, that would be an advantage to easily understand how to check them.