AUTOVOX TVC2683 YEAR 1983.

The AUTOVOX TVC2683 is a 26 inches color screen with 32 programs and PLL synthesized tuning system.

On the front are present 2 speaker system sound and power button.

It's the first AUTOVOX TV color Television model featuring the PLL Frequency synthesized tuning system with a microcomputer servo system which consist in a method for tuning a television receiver having automatic frequency control to the carrier frequency of a selected broadcast channel with an associated channel number including generating a variable frequency signal by means of a local oscillator, generating a reference frequency signal by means of a reference oscillator, and generating a local oscillator correction signal for matching an intermediate frequency signal derived from said local oscillator signal and the carrier frequency signal with a predetermined nominal intermediate frequency signal, said method being characterized by the use of a microcomputer and comprising:
generating binary signals representing first and second digital tune words, said digital tune words representing a selected channel;
storing said first and second digital tune words in a first data memory in said microcomputer;
reading said first and second digital tune words from said first memory and generating a divided-down local oscillator frequency by the use of said first digital tune word and a divided-down reference oscillator frequency by the use of said second digital tune word;
comparing said divided-down local oscillator and reference frequencies and generating a control signal representative of the difference in frequency of said divided-down local oscillator and reference frequencies;
coupling said control signal to said local oscillator for causing it to be locked to the frequency of said received carrier signal;
mixing the local oscillator frequency signal and the carrier frequency signal to generate an intermediate frequency signal;
comparing said intermediate frequency signal with said predetermined nominal intermediate frequency signal and providing a tuning voltage to said microcomputer, said tuning voltage being indicative of the magnitude and direction of a tuning error between said intermediate frequency signal and said predetermined nominal intermediate frequency signal;
incrementally adjusting the reference oscillator frequency by means of a tuning signal provided to said reference oscillator by said microcomputer in response to said tuning voltage;
detecting when the incrementally changing, divided-down reference oscillator frequency causes the intermediate frequency signal to pass said predetermined nominal intermediate frequency signal; and
incrementally stepping the divided-down reference oscillator frequency back a predetermined number of steps following the passage of said predetermined nominal intermediate frequency signal by said intermediate frequency signal in tuning said television receiver to the selected channel.

PLL SYNTHESIZED TUNING System Concepts:

INTRODUCTION Digital tuning systems are fast replacing the conventional mechanical systems in AM FM and television receivers The desirability of the digital approach is mainly due to the following features * Precise tuning of station frequencies
* Exact digital frequency display
* Keyboard entry of desired frequency
* Virtually unlimited station memory
* Up down scanning through the band
* Station ‘‘search’’ (stop on next active station)
* Power on to the last station
* Easy option for time-of-day clock In addition
" recent "developments in large scale integrated circuit technology and new varactor diodes for the AM band have made the cost-benefit picture for digital tuning very attractive System partitioning is extremely important in optimizing this cost-benefit picture as will be discussed.

SYSTEM DESCRIPTION
A simplified block diagram of a typical digitally tuned receiver is shown in Figure 1 Notice this receiver could be one for AM FM marine radio or television it makes no difference The frequency synthesizer block generates the local oscillator frequency for the receiver just as a conventional mechanical tuner would However the phase-locked-loop (PLL) acts as an integral frequency multiplier of an accurate crystal controlled reference frequency while the mechanical type provides a continuously variable frequency output with no reference Some method of controlling the value of the multiplier for channel tuning must be provided The other RF IF and audio video circuitry will be the same as in the mechanical tuning method There are many different ways to partition the frequency synthesizer system to perform the digital tuning function................


........................and a high modularity chassis (130) combined with a 2 way speakers system.

It has a Transistorized horizontal deflection circuits  made up of a horizontal switching or output transistor, a diode, one or more capacitors and a deflection winding. The output transistor, operating as a switch, is driven by a horizontal rate square wave signal and conducts during a portion of the horizontal trace interval. A diode, connected in parallel with the transistor, conducts during the remainder of the trace interval. A retrace capacitor and the deflection yoke winding are coupled in parallel across the transistor-diode combination. Energy is transferred into and out of the deflection winding via the diode and output transistor during the trace interval and via the retrace capacitor during the retrace interval.
In some television receivers, the collector of the horizontal output transistor is coupled to the B+ power supply through the primary windings of the high voltage transformer.

Now that the new Philips 30AX tube has put in an appearance, some details can be filled in. The new tube has been developed from the 20AX, which has been in production since 1974, but brings with it several important advances. First, no dynamic convergence, static convergence, purity or raster correction adjustments are necessary. Secondly the new yoke design gives improved deflection sensitivity, a straight NS raster, and reduced EW raster distortion. Due to the close mechanical tolerances and the inclusion of positioning bosses on the tube bowl, the tube and yoke can be aligned simply by being pushed together - any 30AX yoke will automatically match any 30AX tube of the appropriate size. Thirdly the newly designed electron gun gives a sharper spot, with greater focus uniformity over the screen area. An internal magnetic ring is used to give correct purity and static beam convergence, in place of the multipole unit used in previous in -line gun tube designs. This results in a strikingly compact assembly. The automatic yoke/tube alignment does away with the need for preset mechanical tilt and shift adjustments which, Philips point out, correct one error by introducing another. The new tube is being produced in the 26, 22 and 20in. screen sizes. The power consumption of a set fitted with the 30AX is typicaly 100W compared to 120W with the 20AX system, at 1.2mA beam current and with an e.h.t. of 25kV. This compares with 88W for a set fitted with a 90° narrow -neck tube and hybrid yoke, under the same conditions.
The set is sporting the PHILIPS 30AX SYSTEM CRT.The 30AX system, which Philips introduced in 1979, is an important landmark in the development of colour picture systems. With previous systems the assembly technician had to workthrough a large number of complicated setting-up procedures whenever he fitted a television picture tube with aset of coils for deflecting the electron beams. These procedures were necessary to ensure that the beams for the three colours would converge at thescreen for every deflection. They are no longer necessary with the 30AX system: for a given screen format any deflection unit can be combined  with any tube to form a single 'dynamically convergent' unit. A colour-television receiver can thus be assembled from its components almost as easily as a monochrome receiver. The colour picture tube of the PHILIPS 30AX system displays a noticeably sharper picture over the entire screen surface. This will be particularly noticeable when data transmissions such as Viewdata and Teletext are displayed. This has been achieved by a reduction in the size of the beam spot by about 30%. Absence of coma and the retention of the 36.5 mm neck diameter have both contributed to increased picture sharpness. Coma has been eliminated by means of corrective field shapers embedded in the deflection coils which are sectionally wound saddle types. The new deflection unit has no rear flanges. enabling uniform self-convergence to be obtained for all screen sizes. without special corrections, adjustments, or tolerance compensations. Horizontal raster distortion is reduced and no vertical correction is required. One of the inventions in 30AX is an internal magnetic correction system which obviates static convergence and colour purity errors. This enables the usual multiple unit to be dispensed with. together with the need for its adjustment !  New techniques have been employed to achieve close tolerance construction of the glass envelope. In addition, the 30AX picture tube incorporates two features whereby it can be accurately adjusted during the last stages of manufacture. One is the internal magnetic correction system. The other is an array of bosses on the cone that establish a precise reference for the axial purity positioning of the deflection unit on the tube axis and for raster orientation. During its manufacture, each deflection unit is individually adjusted for optimum convergence. The coil carrier also incorporates reference bosses that co-operate with those on the cone of the tube. ' Since every picture tube and every deflection unit is individually pre-aligned, any deflection unit automatically matches with any picture tube of the appropriate size. The deflection unit has only to be pushed onto the neck of the tube unit it seats. Once the reference bosses are engaged, the combination is accurately aligned and requires no adjustment for convergence, colour purity or raster orientation. With no multiple unit and a flangeless deflection unit, there is more space in the receiver cabinet. Higher deflection sensitivity means that less current is consumed, and consequently less heat is produced. This increases the reliability of the TV receiver again. 30AX means simple assembly. Any picture tube is compatible with any deflection unit of the appropriate size and is automatically self-aligning as well as being self-convergent.

The well-known 20AX features of HI-Bri, Soft-Flash and Quick-vision are maintained in the new 30AX systern.  In their work on the design of deflection coils in the last few years the developers have expanded  the magnetic deflectionfields into 'multipoles', Thisapproach has improved the understanding  of the relations between coil and field and between field and deflection to such an extent that  designing deflection units is now more like playing a difficult but fascinating game of chess than  carrying out the obscure computing procedure once necessary.

The set is build with a Modular chassis design because as modern television receivers become more complex the problem of repairing the receiver becomes more difficult. As the number of components used in the television receiver increases the susceptibility to breakdown increases and it becomes more difficult to replace defective components as they are more closely spaced. The problem has become even more complicated with the increasing number of color television receivers in use. A color television receiver has a larger number of circuits of a higher degree of complexity than the black and white receiver and further a more highly trained serviceman is required to properly service the color television receiver.
Fortunately for the service problem to date, most failures occur in the vacuum tubes used in the television receivers. A faulty or inoperative vacuum tube is relatively easy to find and replace. However, where the television receiver malfunction is caused by the failure of other components, such as resistors, capacitors or inductors, it is harder to isolate the defective component and a higher degree of skill on the part of the serviceman is required.
Even with the great majority of the color television receiver malfunctions being of the "easy to find and repair" type proper servicing of color sets has been difficult to obtain due to the shortage of trained serviceman.
At the present time advances in the state of the semiconductor art have led to the increasing use of transistors in color television receivers. The receiver described in this application has only two tubes, the picture tube and the high voltage rectifier tube, all the other active components in the receiver being semiconductors.
One important characteristic of a semiconductor device is its extreme reliability in comparison with the vacuum tube. The number of transistor and integrated circuit failures in the television receiver will be very low in comparison with the failures of other components, the reverse of what is true in present day color television receivers. Thus most failures in future television receivers will be of the hard to service type and will require more highly qualified servicemen.
The primary symptoms of a television receiver malfunction are shown on the picture tube of the television receiver while the components causing the malfunction are located within the cabinet. Also many adjustments to the receiver require the serviceman to observe the screen. Thus the serviceman must use unsatisfactory mirror arrangements to remove the electronic chassis from the cabinet, usually a very difficult task. Further many components are "buried" in a maze of circuitry and other components so that they are difficult to remove and replace without damage to other components in the receiver.
Repairing a modern color television receiver often requires that the receiver be removed from the home and carried to a repair shop where it may remain for many weeks. This is an expensive undertaking since most receivers are bulky and heavy enough to require at least two persons to carry them. Further, two trips must be made to the home, one to pick up the receiver and one to deliver it. For these reasons, the cost of maintaining the color television receiver in operating condition often exceeds the initial cost of the receiver and is an important factor in determining whether a receiver will be purchased.
Therefore, the object of this invention is to provide a transistorized color television receiver in which the main electronic chassis is easily accessible for maintenance and adjustment.

One of the LAST model series original developed and fabricated by AUTOVOX , any further newer models are made By ZANUSSI or other fabricants and rebranded.



AUTOVOX SpA HISTORY

Giordano Bruno Verdesi founded in Rome in 1933 the Industry Italian Radio engineering, IRI, for the production of professional apparates, but this had its single development in 1945 with the war reconstruction post.

Previewing a strong development of the motorization, with Carlo Daroda, it comes up the Autovox SpA, with the specialization car radio production.

In 1953 the company is upgraded and constructed on the way Pays wages to Rome, the new plant for the production of television sets, antennas, car radio, transistor radio receivers, beyond a production of radiosondes and professional apparatuses for the aeronautical meteorology.

With the planning of the first car radio in the world, the leggendaria Bikini, in 1942 it begins a long season of successes like with the car radio Piper, the blue line with the first tuning electronic, the Kanguro the first car extractable stereo, mythical the Shuttle and Challenger the first car radio with the frequency synthesis, represents for Autovox, the flag stones in the development of new technologies, beyond to a complete range of television set (in black and white) of great reliability and from the pretty aesthetic.

Successively it realizes first in Europe, a color television set with fully transistorized chassis.
(To see the Internal Chassis Just click on Older Post Button on bottom page, that's simple !)

Some references and  Notes:

^ AA.VV., Capitolium vol. 43, 1968, p. 14 ^ "L' agonia dell'Autovox, cinquant'anni di fatti e misfatti romani" - Corriere della Sera, 10 aprile 1996 ^ Bruce Weber, Kusisto envisions rainbows ahead, in Billboard, 15 gennaio 1972. ^ Richard Robson, Motorola UK bows cassette units, in Billboard, 1º luglio 1972.
Istituto Mobiliare Italiano, SpA v. Motorola, 689 F. Supp. 812 (N.D. Ill. 1988), su Justia Law. URL consultato il 26 gennaio 2016. ^ Aldo Grandi, Insurrezione Armata, BUR - Rizzoli, 2005, ISBN 978-88-17-00758-0. ^ Il Mondo vol. 36, 1985, p. 65 ^ "ALLA FINANZIARIA PUBBLICA REL IL 54% DELLA NUOVA AUTOVOX" - Repubblica, 8 giugno 1985 ^ "CONVOCATI DAL TRIBUNALE I CREDITORI DELL' AUTOVOX" - Repubblica, 12 novembre 1987 ^ "AUTOVOX, BATTAGLIA VUOLE IL FALLIMENTO" - Repubblica, 19 novembre 1987 ^ "NOVE ' IN CORDATA' PER SALVARE L' AUTOVOX" - Repubblica, 4 luglio 1992 ^ *** ATTO COMPLETO ***, su www.gazzettaufficiale.it. URL consultato il 21 gennaio 2016. ^ nuova autovox: a nissan Italia complesso aziendale Capena | Agi Archivio, su archivio.agi.it. URL consultato il 20 gennaio 2016 (archiviato dall'url originale l'8 marzo 2016). ^ LA NISSAN FAVORITA PER L'ACQUISTO AUTOVOX - la Repubblica.it, su Archivio - la Repubblica.it. URL consultato il 20 gennaio 2016. ^ AUTOVOX, cordata romana per riaccendere l'autoradio, su archiviostorico.corriere.it. URL consultato il 20 gennaio 2016. ^ Nuova autovox:commissariata anche la autovox video system | Agi Archivio, su archivio.agi.it. URL consultato il 20 gennaio 2016 (archiviato dall'url originale il 2 febbraio 2016). ^ Rifiuti: a Roma nuovo impianto e prima centrale biogas | Agi Archivio, su archivio.agi.it. URL consultato il 20 gennaio 2016 (archiviato dall'url originale il 2 febbraio 2016). ^ ACCORDO AMA - AUTOVOX RISCHIO DI ROTTURA - la Repubblica.it, su Archivio - la Repubblica.it. URL consultato il 20 gennaio 2016. ^ "OCCUPAZIONE. L' Autovox licenzia 234 lavoratori" - Corriere della Sera, 11 giugno 1996 ^ Italia lavoro dismette quota in Roma multiservizi | Agi Archivio, su archivio.agi.it. URL consultato il 20 gennaio 2016 (archiviato dall'url originale il 2 febbraio 2016). ^ Studio Multimediale Hangloose, Impianto di selezione e produzione CDR Salario - Ama Roma S.p.A., su www.amaroma.it. URL consultato il 26 gennaio 2016.

Further reading;

P. Toscano - Le origini del capitalismo industriale nel Lazio: imprese e imprenditori a Roma dall'unità alla seconda guerra mondiale - Cassino, Università degli studi di Cassino, 2002, ISBN 888317089X.