STERN (ZANUSSI) MOD. U17 YEAR 1975.

The STERN (ZANUSSI) MOD. U17 is a 17 inches B/W portable uncommon tellye by form and design.

More like a space age design instead a classic very common rectangular wooden box.



It has 4 programs with mechanic push button with integrated potentiometers for search tuning in each button.

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.

In the end of the 60's  increasingly attention was focused on the varicap diode tuner as the latest, sophisticated means of television receiver frontend tuning in both colour and black and white sets.
 The main purpose of this article is to investigate the servicing problems associated with this comparatively new method of tuning.

First however let's briefly recap on the principles involved in this tuning system:

 The tuners use variable capacitance (or "varicap") diodes as the variable tuning elements: the effective capacitance of the diodes is controlled by the reverse bias applied across them, tuning being achieved by varying this voltage. As the reverse bias across a varicap diode is increased so its junction depletion region widens thus reducing its capacitance.
A VHF/ UHF television tuner is constructed in accordance with the present invention includes a preselector tuned circuit having a solid state voltage controlled capacitor as its tunable element, a radio frequency amplifier coupled to the preselector circuit and alsoother circuit to perfect the signal receiving capability and the application the like.

Considering the Mechanical Tuner Problems:

To get the servicing problems in perspective let us next consider the tuning arrangements previously used.
 The earliest of these, employed on v.h.f., was the switched tuner which was either of the turret or incremental type.
 The turret tuner substituted a coil bearing "biscuit" mounted on the rotating drum or turret when channels were changed. Twelve positions were normally provided, with a fine tuning knob to adjust the local oscillator frequency. As its name suggests the incremental tuner simply added more inductance to the tuned circuits at every downward channel movement: thus the highest inductance was present on channel one and the least on channel 12 (which normally covered 13 as well with manipulation of the fine tuner).
The movement towards u.h.f. TV working, initially with dual standard sets and later with single standard ones, brought about the need for u.h.f. tuners. In the earliest u.h.f. receivers valve tuners which were not particularly efficient were used.

The drive mechanism was usually a dual  speed rotary system calibrated from channels 21 to 68. Experience in the field indicated that 625 line television was in many cases considered by the viewer to be inferior to 405 -line reception, on account of the poor signal to noise ratio achieved by the valve tuners. Many viewers were not prepared to use external u.h.f. aerials of course, having achieved satisfactory reception on v.h.f. with an indoor aerial: this aggravated the situation even more.
Another aspect which caused difficulty was the care needed to tune in a u.h.f. channel using a rotary tuner covering the whole of Bands IV and V. Many viewers simply could not tune in BBC 2  or ZDF or ORF or any channel correctly with such a tuning mechanism, finding that they had passed right over the channel they wanted before realising what they had done.
The advent of transistor tuners rapidly improved the quality of u.h.f. reception but use of a rotary mechanism was continued by many manufacturers. Thus while potential reception was improved the same tuning difficulties remained and viewers continued to gravitate towards 405 line viewing using the "old faithful" switched tuner. The operational breakthrough came with the introduction of the push-button u.h.f. channel change. 

The mechanism is basically simple. Adjustable push buttons press down on a lever bar which in turn rotates the tuner's variable capacitors to the appropriate position. Each button is capable of tuning over the entire u.h.f. bands and this leads to customer confusion at times when after some adjustments which were too heavy handed they find themselves receiving ITV on a BBC button or a ORF and ZDF broadcasting or any channel possible !

Mechanical Faults:

 Mechanical tuning obviously has its snags. There are for example contact springs which earth the tuning capacitor and go intermittent. This gives rise to the most random tuning defects, capable of driving the. most patient viewer to a state of total exasperation. It is also possible for the rotation mechanism to hang up and jam intermittently, or just become sticky, so that the reset accuracy of the mechanism is impaired and the receiver has to be retuned every time the channel is changed.
The vanes in the tuning capacitor can also short out at different settings, thereby eliminating some channels. The  Varicap Tuner It will be seen then that mechanical defects can cause very irritating fault symptoms. If one thinks along the lines that anything mechanical is nasty, then the elimination of mechanical parts can only be to the good.

The logic of this is splendid provided the electronic replacement for the mechanical system is more reliable! Otherwise we are leaping out of the frying pan into the fire! In the light of experience gained with mechanical tuning devices it seems great that with the varicap tuner we have at last dispensed with the dreaded rotary tuning capacitor, replacing it instead with a variable voltage to the tuner. 
Let us think about this however since things are never quite as simple as they first appear. The tuning voltage has to be variable in order to tune the receiver. Obviously then a means of varying the voltage has to be provided to act as the tuning control.
As it is a voltage that has to be varied the tuning control takes the form of a potentiometer., Now we have returned to a mechanical system again, though in a less complex form.
A potentiometer is required for each channel, selected by pressing the appropriate channel button.

We have lost a tuning capacitor and its rotating mechanism and gained a set of pots and selector switches therefore. Provided the pots and switches are mechanically more reliable than the tuning capacitor we should be better off-or should we? 

Need for Voltage Stabilisation.
 The voltage selected by the pots cannot be allowed to drift otherwise the receiver will go off -tune. The voltage supply to the potentiometers has to be stabilised therefore and a stabilising zener diode or integrated circuit (TAA550) .is needed for this purpose.

Any failure in this part of the circuit will give rise to tuning drift or worse, a total loss of reception. A short-circuit TAA550 for example will completely remove the tuning voltage while if it is open circuit the tuning can vary with picture brightness. Likewise any intermittency in the potentiometers or associated switching and/or resistors can also cause problems.

Relative Reliability of Tuners:

 It  will be seen then that in order to lose our troublesome mechanical arrangement we have had to introduce considerably more electronics which we trust are going to be more reliable. In addition we have not so far considered the relative reliability of the varicap tuner itself compared with the mechanical type. Since two r.f. transistors are generally used to compensate for the reduced Q of the varicap tuned circuits we immediately have twice the likelihood of an r.f. stage breaking down! 
And being semiconductors the varicap diodes themselves are more likely to fail than the sections of a ganged tuning capacitor. It is reasonable then to conclude that if mechanical faults are the most prevalent the use of varicap tuners will make life easier. Mechanical faults are generally not too difficult to sort out however and the field engineer can often cope with them in the home. 
Can the same be said of the varicap tuner? It seems that this type of tuner does not need so much attention as its mechanical counterpart but is likely to throw up some much more difficult faults when it does, resulting in bench repairs being needed. So far my own experience has indicated that varicap tuning faults nearly always need servicing on the bench.
Generally speaking it seems true to say that varicap tuners themselves are adequately reliable: the snags result from the tuning system and stabilised power supply.

Tuning Drift with Varicap Tuners:

 If a varicap tuned receiver is constantly drifting off tune the +30V supply should be the number one suspect. It is best to connect an Avometer permanently to the supply so that it can be precisely monitored-if necessary write down the exact voltage measured.
 If the receiver drifts, check the voltage. If it has changed, even slightly, this may well be enough to be the cause of the fault. To pinpoint and confirm the diagnosis aerosol freezer should be applied to the stabiliser i.c. or zener. If the voltage returns to normal or changes wildly for the worse the stabiliser is almost certainly the cause of the trouble and should be replaced.
A prolonged soak test should then be carried out. Another point concerning varicap tuners arises with their use in colour receivers.

 There were  makers of the most expensive colour receiver on the market still didn't use a varicap tuner but instead use a mechanical one. The makers' claim is that the signal to-noise ratio of the varicap tuner is inadequate for their colour standards. Undoubtedly the results obtained on the receiver seem to confirm this. Interestingly, the same manufacturers use varicap tuners in their black -and -white receivers, and the tuning button system is often full of troublesome intermittent contacts. The varicap tuner has its advantages and disadvantages then. Probably the simplest comment would be to say that when it is good it is very very good but when it is bad it is horrid!

Springs component in old tv's tuner :
Most old televisions tuning mechanisms were incorporating coil springs in one form or another for various functions. They can be of the compression type which are wound with spaces between adjacent turns and are intended to be squeezed under pressure : when released they expand to their original form. The mounting springs under record-player turntable units are examples of this type. Alternatively the spring can be of the expanding variety. The coils are wound closely together with adjacent turns touching. The applied tension tends to pull them apart and they exert a contracting force to counteract this and pull the linked components together. In the majority of applications this type is used. Springs often become damaged by being over stretched, or the end loop breaks. More frequently the spring simply becomes detached and disappears. Thus the engineer is faced with the task of finding and fitting a replacement. While it is possible to apply to the makers of the equipment for the right spring this involves delay and of course there is always the problem of identifying the right one out of the many used in the particular mechanism. For this reason many engineers find it more convenient to make their own replacements.

Making a Coil Spring: The operation was quite simple, the equipment needed being a wheelbrace, vice, selection of long screwdrivers with varying diameter shanks and a supply of piano wire of various gauges. The wheelbrace is mounted horizontally in the vice with the wheel uppermost and a screwdriver chosen and inserted into the chuck with the blade foremost. This serves as a mandrel on which the spring can be wound. Because a spring expands slightly in diameter after it is wound the diameter of the screwdriver shank should be a little less than the required inside diameter of the spring. One end of the piano wire should be inserted in the chuck and secured to prevent it coming free. The wheel is then slowly turned and the wire taken up around the screwdriver shank. Keep the wire taut and pull it backward (see Fig. 1) toward the chuck at an angle which keeps the adjacent turns together but does not make a turn ride over the top of its predecessor. When the spring has reached the required length cut the wire and remove the springand screwdriver from the chuck.
As an aid in determining the size of the spring required-especially if the original is lost and there is no pattern to make a comparison with-here are a few observations on the characteristics of coil springs as determined by their dimensions.
Properties of Coil Springs: There are two main properties of a spring, the length to which it can be expanded in comparison to its closed length and its tension or strength in the expanded state. If a coil spring is expanded too far its coils will not return to their original position and the spring is said to be stretched. The amount that a spring can be expanded without becoming stretched is governed by the number of turns and the diameter. The greater the number of turns the less each one has to deviate from its resting position for the complete spring to reach a particular length. Also the greater the diameter the smaller the strain and therefore the more the spring can be expanded. The strength of a spring is related to the gauge of wire and the diameter. A heavy gauge will obviously give greater tension than a lighter one but also a spring with a large diameter will exert less force than a smaller one because as we have seen there is less strain when it is expanded. More force is exerted when the spring is well expanded than when it is nearly closed. If therefore we need a spring that is strong and will stretch a long way we need a large number of turns but not so many that the spring is too long in its closed position. It needs to be of fairly large diameter but as this will make it weaker we must compensate by using a heavy gauge of wire. A weak spring with a long stretch is easily made with thinner wire and a large diameter while a strong spring with a short stretch need have few turns and small diameter. So the various factors are interdependent and although spring design can be quite an exact art-by varying the various parameters-something suitable for the job can usually be made up by judicously estimating the size from the foregoing principles. If a spring has become stretched nothing can be done to restore it by squeezing it up as it has now become a compression spring and the expanded state is its normal one. Rather than winding a completely new spring however the old one can be unwound on a wheelbrace-by reversing the winding process and then rewound tightly. Proper unwinding is essential, not just pulling the spring out straight, because this will produce kinks.
Leaf Springs: From coil springs we turn to leaf springs. These were used as contacts in tuner units and are also were used in the press  button channel selector of the Philips colour TV range and other fabricants. To make a positive contact the leaf spring must be tensioned just right. In the case of the turret tuner the leaf must be so sprung that the contacting stud moves it about a tenth of an inch away from the resting position. If as sometimes happens contact is made without much movement of the leaf there will be little if any pressure and the contact will very likely be intermittent. If on the other hand the leaf is adjusted too far forward it may be caught by the edge of the coil biscuit and crumpled when the turret is rotated.
 Moreover, using this arrangement, the only indication--during adjustment--of which channel is selected is by station identification.
Power switch and other command are located upside.



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 !!!!