VOXSON T5647CD YEAR 1978.

The VOXSON T5647CD is a 22 inches color television with 16 programs Frequency synthesized tuning system based around PHILIPS TRD.

Was first VOXSON model featuring the PHILIPS 20AX SYSTEM CRT TUBE.

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.

Was featuring a OSD for channel and program numbering.

The set is a first in featuring  a new set of PAL decoder chips which has been introduced by Siemens, the TDA2560/TDA2522/TDA2530. The first two of these second -source the latest Philips/Mullard decoder i.c.s, with the TDA2560 as luminance and chrominance signal amplifier and the TDA2522 as the reference oscillator/chrominance demodulator. Interesting features of this set up are the fact that the burst signal passes through the chrominance delay line and the fact that the reference oscillator operates at 8.86MHz, a digital divider providing exactly 90° phase displaced 4.43MHz outputs without the need for a phase shift coil. The first UK produced chassis to use these i.c.s is the Tandberg CTV3, the larger UK setmakers staying for the time being with the TBA560C/TBA540/TCA800 combination. The third i.c. from Siemens is the TDA2530 which supersedes the well known TBA530 luminance/colour-difference signal matrix- ing i.c. The TDA2530 contains a negative feedback driver amplifier and internal clamping in addition to the matrixing network.

This model is even showing the use of a complex LOGIC BOARD to feature some functions in group with other ASIC's to feature and implement PHILIPS DICT TRD - TUNING REMOTE DIGITAL, the set doesn't use any kind of Ucontroller or microprocessor to obtain complex tuning synthesizer functions .(SAB2024 SAB2022 SAB1016 SAB2015 SAB3012)

PHILIPS DICT (TRD - TUNING REMOTE DIGITAL RC4) TUNING SYSTEM IN BRIEF.
A wide variety of "search" or "signal seeking" tuning systems for radio and television receivers are known which provide for automatically tuning only those channels which have acceptable reception characteristics and for skipping past thosechannels which have unacceptable reception characteristics. Such tuning systems typically include a number of signal detectors for determining when a received RF carrier has acceptable reception characteristics. For example, a search type tuning systemfor a television receiver may include: an AFT (automatic fine tuning) detector for determining when an IF carrier derived from the received RF carrier has a frequency within a predetermined range of its desired value; and AGC (automatic gain control)detector for determining when the received RF carrier has an amplitude greater than a predetermined value; and a synchronization detector to determine when synchronization pulses derived from the received RF carrier have the proper frequency.

Tuning systems are also known which include a memory having memory locations associated with each channel in a tuning range for storing information as to whether the associated station or channel is preferred or not. Such "memory" type tuningsystems may be utilized as an alternative to the "search" type tuning systems to select only those channels with acceptable reception characteristics in a given location.

Both "search" and "memory" type tuning systems require a considerable amount of complex and expensive circuitry, in addition to the basic tuning system for tuning each channel in a tuning range, for tuning only those channels with acceptablereception characteristics. Thus, there is a need for a tuning system which requires only a relatively small amount of circuitry in addition to the basic tuning system for tuning only channels with acceptable reception characteristics.

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.

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. 

All transistor color VHF/UHF TV receiver powered from AC net 220V/50Hz.Woodencabinet.


VOXSON was an Italian manufacturer site in Rome in Italy.

It was founded in 1952 by the engineer Arnaldo Piccinini with the name FARET, which stays for Fabbrica Apparecchi Radio e Televisione S.p.A..

The activity begun with radio and television fabrication factory.

It have had almost an immediate success on the market and at the end of the 1950's it have great penetration in the market with lot of sales even in extra market such as Germany.



With some unclear involvements in the 1980's VOXSON was sinking , and with classics Italian industry destroy style it was treatened like a tennis ball between that and this guy and mate; and all of this degraded rapidly the original identity of this industry.

Today VOXSON is selling LCD crap like many others with parts coming from there and there. (china ofcourse)

The destiny of such industry seems all around the same.


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

Further Notes and readings:

^ Produce autoradio da ventisei anni, in L'Unità, 28 ottobre 1977. ^ G. Dell'Aquila, Alla Voxson non bastano o e sovvenzioni, in L'Unità, 30 agosto 1977. ^ F. Ferrarotti, La città come fenomeno di classe, Editore Franco Angeli, 1975, p. 69 ^ A. Castagnoli, E. Scarpellini, Storia degli imprenditori italiani, Einaudi, 2003, p. 333 ^ (EN) "EMI buys 50 P.C. of Voxson, TV Maker", articolo della rivista Billboard del 24 aprile 1971. ^ "VOXSON / L'EMI VUOLE CEDERE IL POSTO ALLA GEPI", articolo del periodico L'Espresso vol. 21, numero 8 del febbraio 1975. ^ Atti Parlamentari - Camera dei Deputati, SEDUTA DI GIOVEDÌ 29 SETTEMBRE 1977 (PDF), su Legislature.Camera.it, 29 settembre 1977. URL consultato il 22 gennaio 2019.

 ^ Dal sito credfed.it ^ Informazione tratta dal sito europeanmemories.eu ^ "ITT E REL DANNO VITA ALLA VIDITAL ASSORBIRA' 750 LAVORATORI VOXSON", Repubblica, 8 febbraio 1985 ^ "VA A FONDO LA VOXSON COSTRETTA A LICENZIARE", Repubblica, 11 settembre 1987 ^ "QUESTO IL FALLIMENTO REL 377 MILIARDI SPESI NEL NULLA", Repubblica, 2 ottobre 1987 ^ "LA REL ENTRA NELLA VOXSON PER SALVARE 300 OCCUPATI", Repubblica, 9 ottobre 1987 ^ "BATTAGLIA DA' IL VIA AL RIFINANZIAMENTO DELLA VOXSON", Repubblica, 22 ottobre 1987 ^ "SOMMERSI E SALVATI CON I SOLDI REL", Repubblica, 19 ottobre 1990 ^ "REL LIQUIDATA LO STATO 'ESCE' DALL'ELETTRONICA", Repubblica, 21 dicembre 1990 ^ "la Maserati suona l' ultima sirena", Corriere della Sera, 30 marzo 1993 ^ "Aspettando Rete4 Di Stefano fa trading", Corriere della Sera, 25 febbraio 2008