The STERN (ZANUSSI) UBG2231 is a 22 Inches color television with Ultrasonic remote and 16 program preselection and a uncommon VU Meter tuning level search system.
The STERN (ZANUSSI) UBG2231 was first Zanussi tv color set featuring a RCA P.I.L. CRT TUBE with a slightly redesigned chassis anyway highly modular and robust.
This models and others from that era were featuring the ZANUSSI CHASSIS BS352 which for last time were using line deflection stages with Thyristors circuits.
- Horizontal Beam Deflection and high voltage generating circuits realized with Thyristors circuits.
It's a very good system to use where the line scan coils require large
peak currents with only a moderate flyback voltage an intrinsic
characteristic of toroidally wound deflection coils. The basic thyristor
line output stage arrangement used in all these chassis is shown in
Fig. 1
it was originally devised by RCA. Many sets fitted with 110°, narrow -neck delta -gun tubes used a thyristor line output stage - for example those in the Grundig and Saba ranges and the Finlux Peacock , Indesit, Siemens, Salora, Metz, Nordmende, Blaupunkt, ITT, Seleco, REX, Mivar, Emerson, Brionvega, Loewe, Galaxi, Stern, Zanussi, Wega, Philco. The circuit continued to find favour in earlier chassis designed for use with in -line gun tubes, examples being found in the Grundig and Korting ranges - also, Indesit, Siemens, Salora, Metz, Nordmende, Blaupunkt, ITT, Seleco, REX, Mivar, Emerson, Brionvega, Loewe, Galaxi, Stern, Zanussi, Wega, Philco the Rediffusion Mk. III chassis. Deflection currents of up to 13A peak -to -peak are commonly encountered with 110° tubes, with a flyback voltage of only some 600V peak to peak. The total energy requirement is of the order of 6mJ, which is 50 per cent higher than modern 110° tubes of the 30AX and S4 variety with their saddle -wound line scan coils. The only problem with this type of circuit is the large amount of energy that shuttles back and forth at line frequency. This places a heavy stress on certain components. Circuit losses produce quite high temperatures, which are concentrated at certain points, in particular the commutating combi coil. This leads to deterioration of the soldered joints around the coil, a common cause of failure. This can hav
e
a cumulative effect, a high resistance joint increasing the local
heating until the joint becomes well and truly dry -a classic symptom
with some Grundig / Emerson sets. The wound components themselves can be
a source of trouble, due to losses - particularly the combi coil and
the regulating transductor. Later chassis are less prone to this sort of
thing, partly because of the use of later generation, higher efficiency
yokes but mainly due to more generous and better design of the wound
components. The ideal dielectric for use in the tuning capacitors is
polypropylene (either metalised or film). It's a truly won- derful
dielectric - very stable, with very small losses, and capable of
operation at high frequencies and elevated temperatures. It's also
nowadays reasonably inexpensive. Unfortunately many earlier chassis of
this type used polyester capacitors, and it's no surprise that they were
inclined to give up. When replacing the tuning capacitors in a
thyristor line output stage it's essential to use polypropylene types -a
good range of axial components with values ranging from 0.001µF to
047µF is available from RS Components, enabling even non-standard values
to be made up from an appropriate combination. Using polypropylene
capacitors in place of polyester ones will not only ensure capacitor
reliability but will also lower the stress on other components by
reducing the circuit losses (and hence power consumption).
Numerous circuit designs for completely transistorized television receivers either have been incorporated in commercially available receivers or have been described in detail in various technical publications. One of the most troublesome areas in such transistor receivers, from the point of View of reliability and economy, lies in the horizontal deflection circuits.
As an attempt to avoid the voltage and current limitations of transistor deflection circuits, a number of circuits have been proposed utilizing the silicon controlled rectifier (SCR), a semiconductor device capable of handling substantially higher currents and voltages than transistors.
The circuit utilizes two bi-directionally conductive switching means which serve respectively as trace and commutating switches. Particularly, each of the switching means comprises the parallel combination of a silicon controlled rectifier (SCR) and a diode. The commutating switch is triggered on shortly before the desired beginning of retrace and, in conjunction with a resonant commutating circuit having an inductor and two capacitors, serves to turn off the trace switch to initiate retrace. The commutating circuit is also arranged to turn oft the commutating SCR before the end of retrace.
Most existing television receivers employ electro-mechanical tuners in which a channel-selecting knob is manually rotatable through various positions established by a detent mechanism and which respectively correspond to the twelve vhf channels. At each of such positions of the knob, suitable switch contacts are engaged to activate a respective circuit by which the receiving frequency for the designated channel is obtained. Such electro-mechanical tuners are susceptible to failure because of loose or dirty switch contacts and defects in the detent mechanism. Furthermore, electro-mechanical tuners of the described type become extremely complex and even more unreliable when designed to tune the uhf channels in addition to the vhf channels.
In order to overcome the above problems of electro-mechanical tuners, so-called electronic tuners have been proposed for television receivers. In these proposed electronic tuners, a varactor, that is, an analog voltage-controlled, variable reactance device, such as, a variable capacitance diode, is employed as the tuning element, and the control voltage therefor is obtained either by means of a potentiometer array or a phase-locked loop arrangement. In the case of the potentiometer array, a number of potentiometers are connected between a stable voltage supply and ground, and each potentiometer is adjusted to provide a voltage which, when applied to the varactor by way of a respective solid state switch, will tune the receiver to a respective one of the local channels. Further, manually operable switches are provided to control the solid state switches associated with the several potentiometers. In the foregoing arrangement, it is difficult and costly to obtain stable potentiometers, and rather elaborate mechanical assemblies are required to provide for the adjustment of the several potentiometers so as to correspond to respective local channels.
In the existing
electronic tuners employing a varactor with a phase-locked loop, the
variable frequency output of the varactor controlled tuner is applied
through an amplifier to a prescaler which divides such output frequency
by a fixed number, and the resulting divided frequency is then further
divided, in a variable counter or divider, by a number that is
determined by a preset logic controlled by manually operable
channel-selector switches. The output of the variable counter or divider
is then compared, in a phase comparator, with a stable reference
frequency obtained, for example, from a crystal-controlled oscillator,
with the resulting error signal being used to control or vary the
control voltage for the varactor. The foregoing phase-locked loop
arrangement is disadvantageous in that the amplifier used to raise the
low level of the output of the tuner for driving the digital prescaler
may be costly, and further in that such prescaler has to operate at an
undesirably high input frequency.
Accordingly, it is an object of this invention to provide an improved channel selecting apparatus for a television receiver having a tuner with a varactor or voltage-controlled variable reactance device as its tuning element, and in which the above described problems and disadvantages of the previously proposed channel selecting apparatus for electronic tuners are avoided.
More particularly, it is an object of this invention to provide a channel selecting apparatus, as aforesaid, which can be easily and inexpensively formed as an integrated circuit, and which is capable of tuning the associated television receiver to any desired channel with very high accuracy and reliability.
Another object is to provide a channel selecting apparatus, as aforesaid, which is devoid of any potentiometers or variable resistors for establishing the control voltage of the varactor, thereby to avoid the problems that may arise from the high contact resistance or changes in the resistance value of potentiometers that can occur due to vibration, temperature variations or simply with time.
Still another object is to provide a channel selecting apparatus, as aforesaid, which may be very simply preset or programmed for determining the local channels that are to be received.
In accordance with an aspect of this invention, in a channel-selecting apparatus for a television receiver having a tuner with a varactor as its tuning element, digital codes representing or identifying respective channels are stored at respective addresses in a memory, and a digital-to-analog converter provides an analog control voltage for the varactor in correspondence to each digital code selectively read out of the memory in a channel selecting mode of the apparatus. Further, in a programming mode of the apparatus, changing, digitally coded counts of a counter which is counting sweep pulses are applied to the digital-to-analog converter for similarly controlling the varactor and selected counts of the counter, for example, those which result in the appearance on the receiver screen of pictures or test patterns broadcast on selected local channels, are written at selected addresses in the memory as the channel identifying codes.
In preferred apparatus according to this invention, the digital-to-analog converter is constituted by a pulse-width modulator which produces a chain of pulses at a constant repetition rate with the widths of such pulses being varied in dependence on the absence of coincidence between a circulating digital code and the digitally coded count from the counter as established either by read out of a channel identifying digital code from the memory or by counting of the sweep pulses, and the output of the pulse-width modulator is passed through a low pass filter to provide the analog control voltage of the varactor in dependence on the modulated pulse width.
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.
NOTE: This series was advertised in a well known italian football advert as ZANUSSI ELETTRONICA TV COLOR.
EDIT:
From RINO's Comment:
" the analog indicator in the tuning area of that tellye was the Zanussi cheap answer to the Grundig and Philips "green bar" (usually growing from left to right) used during that times to graphically indicate the tuning progress and channel location.
- That TV was also branded REX. "
FROM ME, FRANK, AUTHOR:
In the prior art it has been a common practice to provide ordinary mechanical switches for band switching the high and low bands of the VHF tuner and the UHF tuner. Moreover, printed circuit type switches have been utilized in an effort to overcome the usual problems associated with mechanical switches. However, printed circuits have not provided the answers for such mechanical problems as wear, contact failure, and lack of reliability even though the cost is undesirably increased.
Additionally, total electronic tuning systems using logic and digital techniques have been proposed for use with varactor tuners. In one known example, channel numbers are coded into binary numbers and the selection of a preset voltage on varactor diodes is made by a corresponding binary coded signal.
However, electronic tuning systems using logic and digital systems appear to be relatively expensive, require a large number of components, and have a reliability and repeatability factor which is relatively unknown in the industry. Moreover, repair and service problems associated with such a departure from known and more frequently employed techniques remains an unknown factor.
Additionally, it is highly desirable to provide some form of visual indicating apparatus whereby an operator is aware of the approximate tuning of the receiver. Obviously, the provision of such visual indicating apparatus at a minimum cost of materials and labor is of utmost importance.
A signal receiver having VHF and UHF varactor tuners and a channel indicating group for the upper and lower VHF channels and for the UHF channel includes band switching circuitry for selectively coupling a plurality of power sources to the tuners in accordance with activation of a particular channel indicating group. Also, the band switching circuitry is utilized in conjunction with a channel indicating meter circuit for providing a visual indication of the channel selected in each one of the channel indicating groups. It is well known that such a voltage is closely related with the tuning frequency and thus the selected transmitting station. In the receiving equipment employing such a tuning apparatus, it is most preferred to provide an indicator which indicates a tuned frequency and/or selected transmitting station. For that purpose it would be obvious to those skilled in the art to employ a visual indication by means of a volt meter for indicating the voltage applied to the voltage controlled variable capacitance diode in terms of a tuned frequency and/or a selected transmitting station.
Many controls are anyway local.
Zanussi was an Italian producer of home appliances that in 1984 was bought by Electrolux . Zanussi is a leading brand for domestic kitchen appliances in Europe. Products have been exported from Italy since 1946.
The Zanussi Company began as the small workshop of Antonio Zanussi in 1916. The enterprising 26-year-old son of a blacksmith in Pordenone in Northeastern Italy began the business by making home stoves and wood-burning ovens.
After his father death in 1946 “Lino Zanussi” became the President of the company.
In the early 1970s Zanussi sold a lot in the UK and for some time after under the “Zoppas” brand, name which had been acquired, making Zanussi the first largest Italian appliance maker. They also produced washing machines Hotpoint for Hotpoint at this time which were very reliable and highly rated by users and engineers.
In the late 1970s and into the early 1980s the company had a range of washing machines which used an induction motor with a clutch pulley system. Again this range proved extremely popular and very reliable.
During this period Zanussi Professional, the catering range of appliances for commercial use, became a separate division in its own right.
In the early 1980s Zanussi launched the Jetsystem washing machine range to great acclaim whilst at the same time running the “Appliance Of Science” advertising campaign which is acknowledged as one of the most successful marketing campaigns of all time, in fact still remembered by many today. This gave the brand the impression of being forward thinking and innovative.
Zanussi has recently been rebranded as Zanussi-Electrolux in line with many other Electrolux brand names. Since that time many Zanussi appliances share common components and parts with the rest of the Electrolux range, primarily Electrolux, Tricity Bendix and AEG although it is worth noting that the “John Lewis” branded machines sold by the John Lewis Partnership in the UK are effectively rebranded Zanussi appliances.
In the late 1980s Zanussi launched the split tank design known as the “Nexus Tub” design which endures to this day with little change. The tub, base and certain other parts are made from a plastic material known as “Carboran” which can be re-used several times if recycled. To this day neither Zanussi or Electrolux has provided any way to return this material for recycling purposes.
Up until the end of the 1980s Zanussi service was run from Slough and was a network of independent repairers who gave an unparalleled service level. It is generally acknowledged within the industry that this service network was the best that there has ever been in the UK.
In the early 1990s Electrolux instigated amalgamating all its UK brands under one service entity. This entity was split, dependent on region, between the Zanussi service agents and the local Electrolux Service Centre. In general those in a high population density area where given to the Electrolux employed centres. Tricity Bendix, Electrolux and AEG as well as Zanussi were all to be serviced by the one network.
This was changed in the late 1990s and early 2000s as Electrolux sold or gave away the regional service centres, generally to the existing management or to area managers to run as independent businesses.
This service network was rebranded and became Service Force which still exists today but is, once again, all operated by independent service companies who repair and supply spare parts for all of the brands.................
..........................when the president Lino Zanussi died in a plane crash in June 1968 - Zanussi
Industries was the first Italian manufacturer of white goods and employs approximately 13000 employees.
When the Zanussi group of Pordenone lives a first phase of financial stress then Lamberto Mazza, who succeeded Lino Zanussi, decides to liquidate some social funds with share capital held by Guido Zanussi causing an outlay of 16 billion lire of that era.
Despite the Huge outlay to cope with such a withdrawal, the group aquired, in the course of 1970, competitor like Zoppas the other big Italian manufacturer of household appliances, which was,
significantly in debt due of an acquisition of Triplex in Solarolo and a construction of the new plant in Susegana.
The Zoppas, whose factories were located in Conegliano Veneto (TV), has a history quite similar to Zanussi: it is in fact founded by Ferdinand Zoppas in 1926 as an artisan company repair of wood-burning stoves and then spread widely and rapidly under the leadership of his sons Augusto and Gino.
Zanussi president, Lamberto Mazza, alleged a plan to achieve an optimal size to compete at the European level if not the world, strengthening the shares held by Zanussi on the Italian market to avoid the entry of foreign competitors (in particular the U.S. Westinghouse).
The Financial stress imposed on Zanussi by acquisition of Zoppas and, simultaneously, the increase in the incidence both of labor costs and reasons of rise up of activity intensity (In the space of a short pass from 13,000 employees to 24,000 units?) is faced with:
a. the sale to the German AEG-Telefunken
an amount equal to 25.01% of the Zanussi S.p.A.
(The operational holding company of the group)
(The share of ownership AEG-Telefunken is subsequently recognized in 1978 by Voet-Alpine.)
b. to loans from Italian Istituto Mobiliare
(IMI);
c.
about a loan of about two hundred million marks
disbursed in 1974 from Dresden Bank.
The union conflicts, the impact of labor costs (in 1974 Zanussi occupies nearly 31,000 employees), the Debt contract with institutions credit and the first oil shock induce Lamberto Mazza to start a rapid process of diversification The core of this strategy is, however, the belief that the market of appliance White has come to its stage of maturity, with a saturation level and the consequent reduction of typical viability.
Therefore, in this back of years Zanussi invests substantial financial resources to acquiring control of businesses;
(The process of growth of Zanussi, nevertheless sees the creation of new realities companys as a result of corporate spin-offs.
Considering, for example,
Zanussi Grandi Cucine SpA, Zanussi Grandi Impianti
SpA, Air Zanussi SpA, Zanussi Components for Construction SpA, the Industrialised Building ZanussiFarsura SpA to subsidiaries Iberian Zinsa-Zanussi Industrial SA Compania SA and Industrias Electrodomesticas,
and Lastly Anglo-Saxon Iaz International Ltd., was established in 1979
well as the company insurance and financial intermediation
group, called Infinas S.p.A.) with few exceptions activities not related with the core business.
In particular, remembering the concentrations of corporate sectors relating to paper (Paper Mill Galvani SpA, Cartopiave SpA and subsidiaries Cartosud and Silica), electronic (Ducati Electrical, Electronics-Inelco), construction (Seicom-Building for Integrated Components SpA), metallurgical (Smalteria and Metallurgical Veneta SpA), hotel (Borsa SpA) of furniture (Galvani Porcelain SpA, Sambuceto SA, Meson's Spring SpA SpA and its subsidiaries and Pagnucco SpA), components (Ilpea Gomma SpA), photographic equipment ( Fotomec San Marco SpA) of entertainment
(Udinese Calcio SpA) and solar photovoltaics.
(The investments of Zanussi happenned sometimes even in the indirect form
which is made through the CISVE (Industrial Consortium
Economic Development), founded by Lamberto Mazza in quality of
President of the association of Industrialists of Pordenone, as well, since 1978, through the Industrial Finance SpA, a company financial system constituted specifically for that.)
the Organization Company is formed in a matrix in which the divisional activities and are then grouped into the following sections:
1.apparatus for heating;
2.components for Building;
3.solar panels;
4.apparatus Idronet (for potability of the water);
5.components;
6.apparatus different from electronic television sets.
But when the financial situation Worsened in 1983,
Zanussi family the shareholder majority, distrusted Lamberto Mazza replacing him
initially with Umberto Cuttica, former manager of FIAT,
then later with Gianfranco Zoppas, husband of Antonia Zanussi and son Lino.
The corporate reorganization plan was then prepared by the new management and was designed to focus the now scarce financial resources in the core business of group, to continue or to divest a number of activities not closely related ( Air Zanussi, Zanussi Construction Industrialized, Zanussi Electronics, Paper Mill Galvani,Pagnucco, Fotomec, New Cartopiave) , thus preparing the field for the sale of the Entire group to Electrolux, the Swedish multinational leader in field of white goods.
Stern / REX / Zanussi / Seleco (WAS) is an electronics company based in Pordenone, Friuli Venezia Giulia, Italy. It is part of Super//Fluo, who bought the rights in August, 2006, along with Brionvega and Imperial.
Sèleco was born as in 1965 as a spin-off from the home appliances maker Zanussi. In the first years of his life, Seleco produced almost black and white televisions with the Zanussi or Rex brand. The company was being sold in 1984, and was first acquired by Gian Mario Rossignolo. He first became president and then main stockholder.
During the 1980s, the company launched worldwide marketing campaigns and began sponsoring some of the most famous Italian soccer team, such as Lazio A.S..
During the '90s, the company was mainly concentrated on the production of pay-tv decoders, but in 1993 suffered from a loss of competitivity. With the intent to reshape its position and to get gave new life to the company, Gian Mario Rossignolo bought Brionvega from the Brion family, the founder. This attempt get to nowhere, so the company was forced to declare failure in 1997. During the years, Sèleco has passed through ups and downs, at the end being overcome by the continuous changes in the electronics world.
After the crack-down, the company and all its interests were bought by the Formenti family. That gave life to the Seleco-Formenti Group, owner of the rights for the brands Sèleco, Rex, Phonola, Imperial, Stern, Phoenix, Televideon, Kerion and Webrik.
The Formenti family re-launched the company with the production of CRT-TVs. In 2000, the company suffered of a strong crisis, following the price dumping made by Turkish manufacturers. That seems to led to end of the Sèleco and Brionvega story, as the Sèleco-Formenti Group was forced to liquidation.
In 2004, the rights for the radio branch were bought by Sim2 Multimedia, and all the television interests (for the brands Sèleco, Brionvega and Imperial) were acquired by Super//Fluo in August 2006.
THIS INDUSTRY IS TODAY DEAD !!!!
The STERN (ZANUSSI) UBG2231 was first Zanussi tv color set featuring a RCA P.I.L. CRT TUBE with a slightly redesigned chassis anyway highly modular and robust.
This series was first using an ITT specific Ics tuning technology basis and anyway an ultrasonic carrier for remote controls.The new colour picture tube introduced in the UK by Thorn and developed in the US by RCA has an abundance of novel features designed to make it easier to operate and perhaps cheaper to produce. It arrives in an aura of snappy abbreviations such as PST ("precision static toroid") and ITC ("integral tube components") but the proud inventors for some reason insist on giving its full name, Precision In - Line System, the full treatment on each appearance. It seems inevitable that others will have no such inhibitions, so we shall draw comparisons between the new PI tube, the standard shadowmask tube and the Sony Trinitron. These are the only colour large scale production at present. Over twenty years have passed since RCA introduced the shadowmask cathode-ray tube, the first colour television display device to be mass produced. For most of this time it has remained the only colour picture tube available and it is now prodUced under licence to the inventors by many manufacturers all over the world. Detail improvements have been made of course but the basic scheme has remained unchanged: three electron guns in a triangular (or "delta") formation, a shadowmask etched with a pattern of tiny holes and a corresponding array of red, green and blue phosphor dots on the screen. In the last few years the Sony Trinitron has appeared and soon established itself as a display device for use in the small screen portable receivers for which it was designed. The three electron guns in this tube are closely spaced side by side in a horizontal plane. The "shadowmask" contains vertical slits instead of holes and the screen is composed of vertical phosphor stripes in a red -green- blue sequence.
This models and others from that era were featuring the ZANUSSI CHASSIS BS352 which for last time were using line deflection stages with Thyristors circuits.
- Horizontal Beam Deflection and high voltage generating circuits realized with Thyristors circuits.
The massive demand for colour television receivers in Europe/Germany
in the 70's brought about an influx of sets from the continent. Many of
these use the thin -neck (29mm) type of 110° shadowmask tube and the
Philips 20AX CRT Tube, plus the already Delta Gun CRT .
Scanning
of these tubes is accomplished by means of a toroidally wound
deflection yoke (conventional 90° and thick -neck 110° tubes operate
with
saddle -wound deflection coils). The inductance of a toroidal yoke is
very much less than that of a saddle -wound yoke, thus higher scan currents are required.
The deflection current necessary for the line scan is about 12A peak
-to -peak. This could be provided by a transistor line output stage but a
current step-up transformer, which is bulky and both difficult and
costly to manufacture, would be required.
An entirely different
approach, pioneered by RCA in America and developed by them and by ITT
(SEL) in Germany, is the thyristor line output stage. In this system the
scanning current is provided via two thyristors and two switching diodes
which due to their characteristics can supply the deflection yoke
without a step-up transformer (a small transformer is still required to
obtain the input voltage pulse for the e.h.t. tripler). The purpose of
this article is to explain the basic operation of such circuits. The
thyristor line output circuit offers high reliability since all
switching occurs at zero current level. C.R.T. flashovers, which can
produce high current surges (up to 60A), have no detrimental effects on
the switching diodes or thyristors since the forward voltage drop across
these devices is small and the duration of the current pulses short. If
a surge limiting resistor is pro- vided in the tube's final anode
circuit the peak voltages produced by flashovers seldom exceed the
normal repetitive circuit voltages by more than 50-100V. This is well
within the device ratings.
It's a very good system to use where the line scan coils require large
peak currents with only a moderate flyback voltage an intrinsic
characteristic of toroidally wound deflection coils. The basic thyristor
line output stage arrangement used in all these chassis is shown in
Fig. 1it was originally devised by RCA. Many sets fitted with 110°, narrow -neck delta -gun tubes used a thyristor line output stage - for example those in the Grundig and Saba ranges and the Finlux Peacock , Indesit, Siemens, Salora, Metz, Nordmende, Blaupunkt, ITT, Seleco, REX, Mivar, Emerson, Brionvega, Loewe, Galaxi, Stern, Zanussi, Wega, Philco. The circuit continued to find favour in earlier chassis designed for use with in -line gun tubes, examples being found in the Grundig and Korting ranges - also, Indesit, Siemens, Salora, Metz, Nordmende, Blaupunkt, ITT, Seleco, REX, Mivar, Emerson, Brionvega, Loewe, Galaxi, Stern, Zanussi, Wega, Philco the Rediffusion Mk. III chassis. Deflection currents of up to 13A peak -to -peak are commonly encountered with 110° tubes, with a flyback voltage of only some 600V peak to peak. The total energy requirement is of the order of 6mJ, which is 50 per cent higher than modern 110° tubes of the 30AX and S4 variety with their saddle -wound line scan coils. The only problem with this type of circuit is the large amount of energy that shuttles back and forth at line frequency. This places a heavy stress on certain components. Circuit losses produce quite high temperatures, which are concentrated at certain points, in particular the commutating combi coil. This leads to deterioration of the soldered joints around the coil, a common cause of failure. This can hav
e
a cumulative effect, a high resistance joint increasing the local
heating until the joint becomes well and truly dry -a classic symptom
with some Grundig / Emerson sets. The wound components themselves can be
a source of trouble, due to losses - particularly the combi coil and
the regulating transductor. Later chassis are less prone to this sort of
thing, partly because of the use of later generation, higher efficiency
yokes but mainly due to more generous and better design of the wound
components. The ideal dielectric for use in the tuning capacitors is
polypropylene (either metalised or film). It's a truly won- derful
dielectric - very stable, with very small losses, and capable of
operation at high frequencies and elevated temperatures. It's also
nowadays reasonably inexpensive. Unfortunately many earlier chassis of
this type used polyester capacitors, and it's no surprise that they were
inclined to give up. When replacing the tuning capacitors in a
thyristor line output stage it's essential to use polypropylene types -a
good range of axial components with values ranging from 0.001µF to
047µF is available from RS Components, enabling even non-standard values
to be made up from an appropriate combination. Using polypropylene
capacitors in place of polyester ones will not only ensure capacitor
reliability but will also lower the stress on other components by
reducing the circuit losses (and hence power consumption).Numerous circuit designs for completely transistorized television receivers either have been incorporated in commercially available receivers or have been described in detail in various technical publications. One of the most troublesome areas in such transistor receivers, from the point of View of reliability and economy, lies in the horizontal deflection circuits.
As an attempt to avoid the voltage and current limitations of transistor deflection circuits, a number of circuits have been proposed utilizing the silicon controlled rectifier (SCR), a semiconductor device capable of handling substantially higher currents and voltages than transistors.
The circuit utilizes two bi-directionally conductive switching means which serve respectively as trace and commutating switches. Particularly, each of the switching means comprises the parallel combination of a silicon controlled rectifier (SCR) and a diode. The commutating switch is triggered on shortly before the desired beginning of retrace and, in conjunction with a resonant commutating circuit having an inductor and two capacitors, serves to turn off the trace switch to initiate retrace. The commutating circuit is also arranged to turn oft the commutating SCR before the end of retrace.
Most existing television receivers employ electro-mechanical tuners in which a channel-selecting knob is manually rotatable through various positions established by a detent mechanism and which respectively correspond to the twelve vhf channels. At each of such positions of the knob, suitable switch contacts are engaged to activate a respective circuit by which the receiving frequency for the designated channel is obtained. Such electro-mechanical tuners are susceptible to failure because of loose or dirty switch contacts and defects in the detent mechanism. Furthermore, electro-mechanical tuners of the described type become extremely complex and even more unreliable when designed to tune the uhf channels in addition to the vhf channels.
In order to overcome the above problems of electro-mechanical tuners, so-called electronic tuners have been proposed for television receivers. In these proposed electronic tuners, a varactor, that is, an analog voltage-controlled, variable reactance device, such as, a variable capacitance diode, is employed as the tuning element, and the control voltage therefor is obtained either by means of a potentiometer array or a phase-locked loop arrangement. In the case of the potentiometer array, a number of potentiometers are connected between a stable voltage supply and ground, and each potentiometer is adjusted to provide a voltage which, when applied to the varactor by way of a respective solid state switch, will tune the receiver to a respective one of the local channels. Further, manually operable switches are provided to control the solid state switches associated with the several potentiometers. In the foregoing arrangement, it is difficult and costly to obtain stable potentiometers, and rather elaborate mechanical assemblies are required to provide for the adjustment of the several potentiometers so as to correspond to respective local channels.
In the existing
electronic tuners employing a varactor with a phase-locked loop, the
variable frequency output of the varactor controlled tuner is applied
through an amplifier to a prescaler which divides such output frequency
by a fixed number, and the resulting divided frequency is then further
divided, in a variable counter or divider, by a number that is
determined by a preset logic controlled by manually operable
channel-selector switches. The output of the variable counter or divider
is then compared, in a phase comparator, with a stable reference
frequency obtained, for example, from a crystal-controlled oscillator,
with the resulting error signal being used to control or vary the
control voltage for the varactor. The foregoing phase-locked loop
arrangement is disadvantageous in that the amplifier used to raise the
low level of the output of the tuner for driving the digital prescaler
may be costly, and further in that such prescaler has to operate at an
undesirably high input frequency. Accordingly, it is an object of this invention to provide an improved channel selecting apparatus for a television receiver having a tuner with a varactor or voltage-controlled variable reactance device as its tuning element, and in which the above described problems and disadvantages of the previously proposed channel selecting apparatus for electronic tuners are avoided.
More particularly, it is an object of this invention to provide a channel selecting apparatus, as aforesaid, which can be easily and inexpensively formed as an integrated circuit, and which is capable of tuning the associated television receiver to any desired channel with very high accuracy and reliability.
Another object is to provide a channel selecting apparatus, as aforesaid, which is devoid of any potentiometers or variable resistors for establishing the control voltage of the varactor, thereby to avoid the problems that may arise from the high contact resistance or changes in the resistance value of potentiometers that can occur due to vibration, temperature variations or simply with time.
Still another object is to provide a channel selecting apparatus, as aforesaid, which may be very simply preset or programmed for determining the local channels that are to be received.
In accordance with an aspect of this invention, in a channel-selecting apparatus for a television receiver having a tuner with a varactor as its tuning element, digital codes representing or identifying respective channels are stored at respective addresses in a memory, and a digital-to-analog converter provides an analog control voltage for the varactor in correspondence to each digital code selectively read out of the memory in a channel selecting mode of the apparatus. Further, in a programming mode of the apparatus, changing, digitally coded counts of a counter which is counting sweep pulses are applied to the digital-to-analog converter for similarly controlling the varactor and selected counts of the counter, for example, those which result in the appearance on the receiver screen of pictures or test patterns broadcast on selected local channels, are written at selected addresses in the memory as the channel identifying codes.
In preferred apparatus according to this invention, the digital-to-analog converter is constituted by a pulse-width modulator which produces a chain of pulses at a constant repetition rate with the widths of such pulses being varied in dependence on the absence of coincidence between a circulating digital code and the digitally coded count from the counter as established either by read out of a channel identifying digital code from the memory or by counting of the sweep pulses, and the output of the pulse-width modulator is passed through a low pass filter to provide the analog control voltage of the varactor in dependence on the modulated pulse width.
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.
NOTE: This series was advertised in a well known italian football advert as ZANUSSI ELETTRONICA TV COLOR.
EDIT:
From RINO's Comment:
" the analog indicator in the tuning area of that tellye was the Zanussi cheap answer to the Grundig and Philips "green bar" (usually growing from left to right) used during that times to graphically indicate the tuning progress and channel location.
- That TV was also branded REX. "
FROM ME, FRANK, AUTHOR:
In the prior art it has been a common practice to provide ordinary mechanical switches for band switching the high and low bands of the VHF tuner and the UHF tuner. Moreover, printed circuit type switches have been utilized in an effort to overcome the usual problems associated with mechanical switches. However, printed circuits have not provided the answers for such mechanical problems as wear, contact failure, and lack of reliability even though the cost is undesirably increased.
Additionally, total electronic tuning systems using logic and digital techniques have been proposed for use with varactor tuners. In one known example, channel numbers are coded into binary numbers and the selection of a preset voltage on varactor diodes is made by a corresponding binary coded signal.
However, electronic tuning systems using logic and digital systems appear to be relatively expensive, require a large number of components, and have a reliability and repeatability factor which is relatively unknown in the industry. Moreover, repair and service problems associated with such a departure from known and more frequently employed techniques remains an unknown factor.
Additionally, it is highly desirable to provide some form of visual indicating apparatus whereby an operator is aware of the approximate tuning of the receiver. Obviously, the provision of such visual indicating apparatus at a minimum cost of materials and labor is of utmost importance.
A signal receiver having VHF and UHF varactor tuners and a channel indicating group for the upper and lower VHF channels and for the UHF channel includes band switching circuitry for selectively coupling a plurality of power sources to the tuners in accordance with activation of a particular channel indicating group. Also, the band switching circuitry is utilized in conjunction with a channel indicating meter circuit for providing a visual indication of the channel selected in each one of the channel indicating groups. It is well known that such a voltage is closely related with the tuning frequency and thus the selected transmitting station. In the receiving equipment employing such a tuning apparatus, it is most preferred to provide an indicator which indicates a tuned frequency and/or selected transmitting station. For that purpose it would be obvious to those skilled in the art to employ a visual indication by means of a volt meter for indicating the voltage applied to the voltage controlled variable capacitance diode in terms of a tuned frequency and/or a selected transmitting station.
Many controls are anyway local.
Zanussi was an Italian producer of home appliances that in 1984 was bought by Electrolux . Zanussi is a leading brand for domestic kitchen appliances in Europe. Products have been exported from Italy since 1946.
The Zanussi Company began as the small workshop of Antonio Zanussi in 1916. The enterprising 26-year-old son of a blacksmith in Pordenone in Northeastern Italy began the business by making home stoves and wood-burning ovens.
After his father death in 1946 “Lino Zanussi” became the President of the company.
In the early 1970s Zanussi sold a lot in the UK and for some time after under the “Zoppas” brand, name which had been acquired, making Zanussi the first largest Italian appliance maker. They also produced washing machines Hotpoint for Hotpoint at this time which were very reliable and highly rated by users and engineers.
In the late 1970s and into the early 1980s the company had a range of washing machines which used an induction motor with a clutch pulley system. Again this range proved extremely popular and very reliable.
During this period Zanussi Professional, the catering range of appliances for commercial use, became a separate division in its own right.
In the early 1980s Zanussi launched the Jetsystem washing machine range to great acclaim whilst at the same time running the “Appliance Of Science” advertising campaign which is acknowledged as one of the most successful marketing campaigns of all time, in fact still remembered by many today. This gave the brand the impression of being forward thinking and innovative.
Zanussi has recently been rebranded as Zanussi-Electrolux in line with many other Electrolux brand names. Since that time many Zanussi appliances share common components and parts with the rest of the Electrolux range, primarily Electrolux, Tricity Bendix and AEG although it is worth noting that the “John Lewis” branded machines sold by the John Lewis Partnership in the UK are effectively rebranded Zanussi appliances.
In the late 1980s Zanussi launched the split tank design known as the “Nexus Tub” design which endures to this day with little change. The tub, base and certain other parts are made from a plastic material known as “Carboran” which can be re-used several times if recycled. To this day neither Zanussi or Electrolux has provided any way to return this material for recycling purposes.
Up until the end of the 1980s Zanussi service was run from Slough and was a network of independent repairers who gave an unparalleled service level. It is generally acknowledged within the industry that this service network was the best that there has ever been in the UK.
In the early 1990s Electrolux instigated amalgamating all its UK brands under one service entity. This entity was split, dependent on region, between the Zanussi service agents and the local Electrolux Service Centre. In general those in a high population density area where given to the Electrolux employed centres. Tricity Bendix, Electrolux and AEG as well as Zanussi were all to be serviced by the one network.
This was changed in the late 1990s and early 2000s as Electrolux sold or gave away the regional service centres, generally to the existing management or to area managers to run as independent businesses.
This service network was rebranded and became Service Force which still exists today but is, once again, all operated by independent service companies who repair and supply spare parts for all of the brands.................
..........................when the president Lino Zanussi died in a plane crash in June 1968 - Zanussi
Industries was the first Italian manufacturer of white goods and employs approximately 13000 employees.
When the Zanussi group of Pordenone lives a first phase of financial stress then Lamberto Mazza, who succeeded Lino Zanussi, decides to liquidate some social funds with share capital held by Guido Zanussi causing an outlay of 16 billion lire of that era.
Despite the Huge outlay to cope with such a withdrawal, the group aquired, in the course of 1970, competitor like Zoppas the other big Italian manufacturer of household appliances, which was,
significantly in debt due of an acquisition of Triplex in Solarolo and a construction of the new plant in Susegana.
The Zoppas, whose factories were located in Conegliano Veneto (TV), has a history quite similar to Zanussi: it is in fact founded by Ferdinand Zoppas in 1926 as an artisan company repair of wood-burning stoves and then spread widely and rapidly under the leadership of his sons Augusto and Gino.
Zanussi president, Lamberto Mazza, alleged a plan to achieve an optimal size to compete at the European level if not the world, strengthening the shares held by Zanussi on the Italian market to avoid the entry of foreign competitors (in particular the U.S. Westinghouse).
The Financial stress imposed on Zanussi by acquisition of Zoppas and, simultaneously, the increase in the incidence both of labor costs and reasons of rise up of activity intensity (In the space of a short pass from 13,000 employees to 24,000 units?) is faced with:
a. the sale to the German AEG-Telefunken
an amount equal to 25.01% of the Zanussi S.p.A.
(The operational holding company of the group)
(The share of ownership AEG-Telefunken is subsequently recognized in 1978 by Voet-Alpine.)
b. to loans from Italian Istituto Mobiliare
(IMI);
c.
about a loan of about two hundred million marks
disbursed in 1974 from Dresden Bank.
The union conflicts, the impact of labor costs (in 1974 Zanussi occupies nearly 31,000 employees), the Debt contract with institutions credit and the first oil shock induce Lamberto Mazza to start a rapid process of diversification The core of this strategy is, however, the belief that the market of appliance White has come to its stage of maturity, with a saturation level and the consequent reduction of typical viability.
Therefore, in this back of years Zanussi invests substantial financial resources to acquiring control of businesses;
(The process of growth of Zanussi, nevertheless sees the creation of new realities companys as a result of corporate spin-offs.
Considering, for example,
Zanussi Grandi Cucine SpA, Zanussi Grandi Impianti
SpA, Air Zanussi SpA, Zanussi Components for Construction SpA, the Industrialised Building ZanussiFarsura SpA to subsidiaries Iberian Zinsa-Zanussi Industrial SA Compania SA and Industrias Electrodomesticas,
and Lastly Anglo-Saxon Iaz International Ltd., was established in 1979
well as the company insurance and financial intermediation
group, called Infinas S.p.A.) with few exceptions activities not related with the core business.
In particular, remembering the concentrations of corporate sectors relating to paper (Paper Mill Galvani SpA, Cartopiave SpA and subsidiaries Cartosud and Silica), electronic (Ducati Electrical, Electronics-Inelco), construction (Seicom-Building for Integrated Components SpA), metallurgical (Smalteria and Metallurgical Veneta SpA), hotel (Borsa SpA) of furniture (Galvani Porcelain SpA, Sambuceto SA, Meson's Spring SpA SpA and its subsidiaries and Pagnucco SpA), components (Ilpea Gomma SpA), photographic equipment ( Fotomec San Marco SpA) of entertainment
(Udinese Calcio SpA) and solar photovoltaics.
(The investments of Zanussi happenned sometimes even in the indirect form
which is made through the CISVE (Industrial Consortium
Economic Development), founded by Lamberto Mazza in quality of
President of the association of Industrialists of Pordenone, as well, since 1978, through the Industrial Finance SpA, a company financial system constituted specifically for that.)
the Organization Company is formed in a matrix in which the divisional activities and are then grouped into the following sections:
1.apparatus for heating;
2.components for Building;
3.solar panels;
4.apparatus Idronet (for potability of the water);
5.components;
6.apparatus different from electronic television sets.
But when the financial situation Worsened in 1983,
Zanussi family the shareholder majority, distrusted Lamberto Mazza replacing him
initially with Umberto Cuttica, former manager of FIAT,
then later with Gianfranco Zoppas, husband of Antonia Zanussi and son Lino.
The corporate reorganization plan was then prepared by the new management and was designed to focus the now scarce financial resources in the core business of group, to continue or to divest a number of activities not closely related ( Air Zanussi, Zanussi Construction Industrialized, Zanussi Electronics, Paper Mill Galvani,Pagnucco, Fotomec, New Cartopiave) , thus preparing the field for the sale of the Entire group to Electrolux, the Swedish multinational leader in field of white goods.
Stern / REX / Zanussi / Seleco (WAS) is an electronics company based in Pordenone, Friuli Venezia Giulia, Italy. It is part of Super//Fluo, who bought the rights in August, 2006, along with Brionvega and Imperial.
Sèleco was born as in 1965 as a spin-off from the home appliances maker Zanussi. In the first years of his life, Seleco produced almost black and white televisions with the Zanussi or Rex brand. The company was being sold in 1984, and was first acquired by Gian Mario Rossignolo. He first became president and then main stockholder.
During the 1980s, the company launched worldwide marketing campaigns and began sponsoring some of the most famous Italian soccer team, such as Lazio A.S..
During the '90s, the company was mainly concentrated on the production of pay-tv decoders, but in 1993 suffered from a loss of competitivity. With the intent to reshape its position and to get gave new life to the company, Gian Mario Rossignolo bought Brionvega from the Brion family, the founder. This attempt get to nowhere, so the company was forced to declare failure in 1997. During the years, Sèleco has passed through ups and downs, at the end being overcome by the continuous changes in the electronics world.
After the crack-down, the company and all its interests were bought by the Formenti family. That gave life to the Seleco-Formenti Group, owner of the rights for the brands Sèleco, Rex, Phonola, Imperial, Stern, Phoenix, Televideon, Kerion and Webrik.
The Formenti family re-launched the company with the production of CRT-TVs. In 2000, the company suffered of a strong crisis, following the price dumping made by Turkish manufacturers. That seems to led to end of the Sèleco and Brionvega story, as the Sèleco-Formenti Group was forced to liquidation.
In 2004, the rights for the radio branch were bought by Sim2 Multimedia, and all the television interests (for the brands Sèleco, Brionvega and Imperial) were acquired by Super//Fluo in August 2006.
THIS INDUSTRY IS TODAY DEAD !!!!
Hello Frank,
ReplyDeletethe analog indicator in the tuning area of that tellye was the Zanussi cheap answer to the Grundig and Philips "green bar" (usually growing from left to right) used during that times to graphically indicate the tuning progress and channel location. It wasn't for fine tuning. That TV was also branded REX.
Rino
FIXED, THANK YOU!
ReplyDeleteIncredibile!! il mio primo televisore a colori!!
ReplyDeleteQuello che avevamo era però marchiato Zoppas, che comunque era uno dei brand sempre del gruppo Zanussi, quindi probabile che esista anche con altri marchi.
Il modello è comunque questo ad estetica, aveva anche come questo l' indicatore di frequenza dentro il cassettino.
Gran bel televisore, peccato che come elettronica era una baracca, stava 1mese in casa e 1 settimana in assistenza, quando durava molto stava 6mesi senza guastarsi, ricordo anche il guasto più frequente in questo tv che era quando andavi ad accenderlo si spegneva il led e rimaneva morto, spegnevi il tasto e riaccendevi e ricompariva il led e cosi via ..
Ho ancora il telecomando ad ultrasuoni ed i manuali di uso e di assistenza con schemi ecc, che ho conservato fino ad oggi.
Dovrei avere anche i cavi per il registratore a cassette tramite la DIN sul retro, e lo spinotto assurdo per le cuffie, che al epoca trovai solo su un modello Philips di cuffie stereo.
A noi è durato dal 1981 al 1990 ... quando ricordo si iniziò a ristringere verticalmente lo schermo fino a diventare in pochi giorni solo una riga orizzontale (in pratica era partito il verticale!!) lo prese il venditore che ci portò un PHilips 25 pollici OSD Stereo Televideo..
Peccato davvero potessi ritrovarlo il mio buon caro e vecchio Zoppas ..
Questo modello è tenuto davvero benissimo, ha ancora lo sportellino frontale come nuovo, ed anche come estetica è davvero messo bene, con il suo tastone imponente per l'accensione.
Grazie per averlo postato!