AUTOVOX TVC2278 ALTAIR YEAR 1978.

The AUTOVOX TVC2278 ALTAIR is a 22 inches color television with 12 programs manual preselection and manual potentiometers tuning system and no remote control system.

All commands are performed manually and program numbers are displayed with led display in the tuning box.
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 invention relates to a tuning unit with bandswitch for high frequency receivers, especially radio and television receivers, having a potentiometer system for the control of capacity diodes, the said potentiometer system consisting of a plurality of parallel resistance paths along which wiper contacts can be driven by means of screw spindles disposed adjacent one another in a common insulating material housing in which a bandswitch formed of metal rods is associated with each tuning spindle.

In these tuning units, the working voltages of the capacity diodes in the tuning circuits are recorded once a precise tuning to the desired frequency has been performed. A potentiometer tuning system has great advantages over the formerly used channel selectors operating with mechanically adjustable capacitors (tuning condensers) or mechanically adjustable inductances (variometers), mainly because it is not required to have such great precision in its tuning mechanism.

Tuning units with bandswitches formed of variable resistances and combined with interlocking pushbuttons controlling the supply of recorded working voltages to capacity diodes are known. Channel selection is accomplished by depressing the knobs, and the tuning or fine tuning are performed by turning the knobs. The resistances serving as voltage dividers in these tuning units are combined into a component unit such that they are in the form of a ladderlike pattern on a common insulating plate forming the cover of the housing in which the tuning spindles and wiper contacts corresponding to the variable resistances are housed. The number of resistances corresponds to the number of channels or frequencies which are to be recorded. The wiper contact picks up a voltage which, when applied to the capacity diodes determines their capacitance and hence the frequency of the corresponding oscillating circuit. The adjustment of the wipers is performed by turning the tuning spindle coupled to the tuning knob. By the depression of a button the electrical connection between a contact rod and a tuning spindle is brought about and thus the selected voltage is applied to the capacity diodes. Since the push buttons release one another, it is possible simply by depressing another button to tune to a different receiving frequency or a different channel, as the case may be.

 Moreover, using this arrangement, the only indication--during adjustment--of which channel is selected is by station identification.


Was first models series from AUTOVOX with PHILIPS 20AX CRT TUBE.The PHILIPS 20AX system was introduced in Europe in 1975 as the first self converging picture tube/deflection coil, combination for 110° degree deflection and screen sizes up to 26". The system is based on the automatic convergence principle discovered by Haantjes and Lubben of Philips Research Laboratory more than 20 years ago. It makes use of an in-line gun array in conjunction with a specially designed saddle type deflection coil. Residual small tolerance errors are compensated by a simple dynamic four-pole system. The tube is 2 cm shorter than conventional 110° Degree tubes and has a standard 36.5 mm neck in order to obtain good color selection. A slotted mask is used in combination with a stripe-structure screen. Picture sharpness is ensured by an astigmatic electron gun.

The new tube, to be known as the 20AX, has been developed by PHILIPS in conjunction with the parent Philips / Mullard organisation and will be produced by several Philips subsidiary companies on the Continent as well as by PHILIPS in the UK. PHILIPS envisage quantity production of the tube by 1976, mainly for export at first, with large-scale production for UK set - makers starting in 1977. The tube has been developed as "probably the final phase in the design of the 110° shadowmask tube". Its main features are the use of three guns mounted horizontally in line, the use of a shadow - mask with slots instead of circular holes, and a screen with the phosphors deposited in vertical stripes instead of as a pattern of dot triads. It seems therefore that the days of the present delta gun shadowmask tube are now numbered, though considerable production will have to continue for many years to provide replacement tubes for the millions of colour sets already in use. So far as the viewer is concerned however it is important to appreciate the time scale involved (see above) and the reasons for the development of the new tube. There is nothing wrong with the type of shadow - mask tube we have known since the beginning of colour TV: it is able to provide superb pictures. But in its 110° form it does require rather a lot of scan/convergence correction circuitry. If this can be reduced by means of an alternative approach

as with the 20AX tube  considerable benefits in set production and servicing will be obtained. This has been the aim behind the development of the new tube, and the demonstration tube we have seen operating with its associated deflection yoke and circuitry gave a picture every bit as good as we have come to expect from the present "conventional" approach to colour tube design. There are now four colour tubes with in -line guns, the Sony Trinitron (the first to come along), the RCA /Mazda PIL tube, the Toshiba RIS tube and now the PHILIPS 20AX. It is interesting to compare them. The Trinitron is a 90° narrow neck (29mm) tube. It differs from the others in using an aperture grill (slits from top to bottom) instead of a mask behind the screen to shadow the beams and a tube face which is substantially flat in the vertical plane. On the domestic market it is used exclusively in Sony sets and certainly represented a break through in simplifying the convergence circuitry and setting up adjustments required. The Toshiba RIS (rectangular flare, in-line guns, slotted shadowmask) tube has now turned up in the UK in the recently introduced 18in. Sharp Model C1831H. Its most distinctive feature is the rectangu- lar instead of conical tube flare and the rectangular semi -toroidal scanning yoke which is used with this. It is a 110° thick neck (36mm) tube. The convergence arrangements are fairly simple. The most interesting comparisons however are between the PI tube and the 20AX. The first is a 90° tube of the narrow neck variety and features a toroidal yoke which is cemented to the tube- thus if either is faulty the entire tube/yoke assembly must be replaced. The great advantage is that no dynamic convergence adjustments or circuitry are required. It is at present limited to sizes up to 20in. and the designers say that it is not intended as a successor to the standard shadowmask tube above this size. Its depth compares with 110° tubes because of the simplified gun structure used. The PHILIPS 20AX tube differs from it in several respects. First it is basically a 110° tube which can be produced in a whole range of sizes production of 18, 22 and 26in. versions is proposed so that set  makers can use it with a single chassis for models of various sizes. Secondly it uses saddlewound deflection coils which are separate from though accurately aligned with the tube. And thirdly it is a thick neck tube. Unlike the PI tube in which all the gun electrodes except the cathodes are common to all guns the electrodes of each gun in the 20AX are separately available at the base. This means that in addition to RGB drive to the cathodes the grids are available for blanking and beam limiting and the first anodes for background control setting in the normal manner. In fact PHILIPS emphasised that the new tube is entirely compatible with existing colour set techniques  though the whole convergence system is greatly simplified. The basic idea behind these in line gun, slotted mask tubes is that by mounting the guns horizontally in line the convergence errors are confined to the horizontal plane and by applying an astigmatic deflection field these errors are cancelled. This means that a fair amount of cunning in the design of the deflection yoke is required. A saddlewound yoke is more efficient than a toroidal yoke since the deflection fields are totally enclosed.

 In comparison to current 110° PHILIPS tubes the 20AX requires much the same horizontal deflection power but about twice the vertical deflection power (which can be obtained without trouble from modern semiconductor devices). The use of a separate yoke with a tube of this type means that some dynamic convergence controls are still necessary, in order to match the assemblies. PHILIPS refer to these as "tolerance adjustments" rather than "dynamic convergence controls". About seven are required at present though further work is being done on this and by the time sets with the new tube appear we can expect some reduction. A single pincushion transductor is required instead of the two needed with 110° shadowmask tubes of the present variety. In comparison the PIL  tube requires no dynamic convergence adjustments, only some simple tube neck magnets for static setting up. It is a little less efficient however because of the type of yoke employed. Whatever else happens there is no doubt that the vast majority of colour tubes fitted to TVC sets come 1977 will be of the in line gun, slotted mask, vertical phosphor stripe variety. Two further points made by PHILIPS at their demonstration : first, this type of tube requires less degaussing so that there are worthwhile savings in the amount of copper required for the degaussing coils: secondly their new tube, and in fact all PHILIPS monochrome tubes and shortly their colour tubes as well, will incorporate "instant on" guns which come into operation about  five seconds after the set is switched on instead of the 30 seconds or more taken by present tubes. This instant on feature is based on a new heater/cathode assembly in which the use of mica insulators has been avoided. 

Meanwhile we understand that in addition to RCA and, in the UK, Mazda, ITT and Videocolor SA are to produce PIL tubes. Whilst congratulations all round was appropriate on the successful development of these  tubes it does seem a pity that was about to enter for the first time an era of non compatible colour c.r.t.s.

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. Another object of this invention is to provide a transistorized color television receiver in which the electronic circuits are divided into a plurality of modules with the modules easily removable for service and maintenance. The main electronic chassis is slidably mounted within the cabinet so that it may be withdrawn, in the same manner as a drawer, to expose the electronic circuitry therein for maintenance and adjustment from the rear closure panel after easy removal. Another aspect is the capability to be serviced at eventually the home of the owner.

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. (CLICK HERE TO SEE).


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