REX (Zanussi) RC120A YEAR 1976.

The REX (Zanussi) RC120A IS A Little 12 inches B/W Portable television with 5 programs preselection and manual tuning search.

On top side 3 potentiometers for local control of bright - contrast - volume and power switch.
The use of voltage-variable diode-capacitors, such as varactor diodes, permits the electronic tuning of radio receivers and television receivers by the use of DC control voltages; so that the tuning elements no longer need to be intimately associated with the tuner. Thus, the tuned circuits of the tv receivers may be located remotely from the devices used to provide the necessary DC tuning voltages. In addition, the compact size of the voltage-variable diode-capacitor tuning circuits makes it desirable to use such tuning circuits in many tv applications which formerly used mechanically adjusted variable capacitors or the like as the tuning elements.

To employ voltage-variable diode capacitors in pushbutton tvs, however, especially in multiband pushbutton tv sets , a problem exists in providing a "memory," so that operation of a pushbutton will provide consistent tuning of the tv receiver to the station which is to be selected by that pushbutton. In addition it is necessary to provide some means for providing the initial tuning of the tv receiver for each pushbutton location in a manner which is reliable and inexpensive.


It has 3 antennas for both VHF and UHF channels and the possibility to connect to a 12Volt source.

Recently, it has become more popular than ever to watch TV in a car as the number of cars increases. In general, a storage battery of 12 volts is used in small cars while one of 24 volts is used in large cars so that there is a disadvantage that a separate power supply device is required for driving a TV set in compliance with the respective battery used in the car. The present invention relates to a power supply circuit of a television receiver used in an automobile, and in particular to a power supply circuit of a television receiver which enables two different voltages from two kinds of supply respectively mains at 220v and dc 12v.
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 !!!!

REX (Zanussi) RC120A CHASSIS BS201.4 INTERNAL VIEW.

The Zanussi CHASSIS BS201.4 is based On a Heavy monocarrier PCB. All parts are fitted on it even the power supply part.

- SN7600 (Texas Instruments)

- Tba550Q (PHILIPS)


Power supply is realized with mains transformer and Linear transistorized power supply stabilizer, A DC power supply apparatus includes a rectifier circuit which rectifies an input commercial AC voltage. The rectifier output voltage is smoothed in a smoothing capacitor. Voltage stabilization is provided in the stabilizing circuits by the use of Zener diode circuits to provide biasing to control the collector-emitter paths of respective transistors.A linear regulator circuit according to an embodiment of the present invention has an input node receiving an unregulated voltage and an output node providing a regulated voltage. The linear regulator circuit includes a voltage regulator, a bias circuit, and a current control device.

In one embodiment, the current control device is implemented as an NPN bipolar junction transistor (BJT) having a collector electrode forming the input node of the linear regulator circuit, an emitter electrode coupled to the input of the voltage regulator, and a base electrode coupled to the second terminal of the bias circuit. A first capacitor may be coupled between the input and reference terminals of the voltage regulator and a second capacitor may be coupled between the output and reference terminals of the voltage regulator. The voltage regulator may be implemented as known to those skilled in the art, such as an LDO or non-LDO 3-terminal regulator or the like.
The bias circuit may include a bias device and a current source. The bias device has a first terminal coupled to the output terminal of the voltage regulator and a second terminal coupled to the control electrode of the current control device. The current source has an input coupled to the first current electrode of the current control device and an output coupled to the second terminal of the bias device. A capacitor may be coupled between the first and second terminals of the bias device.
In the bias device and current source embodiment, the bias device may be implemented as a Zener diode, one or more diodes coupled in series, at least one light emitting diode, or any other bias device which develops sufficient voltage while receiving current from the current source. The current source may be implemented with a PNP BJT having its collector electrode coupled to the second terminal of the bias device, at least one first resistor having a first end coupled to the emitter electrode of the PNP BJT and a second end, a Zener diode and a second resistor. The Zener diode has an anode coupled to the base electrode of the PNP BJT and a cathode coupled to the second end of the first resistor. The second resistor has a first end coupled to the anode of the Zener diode and a second end coupled to the reference terminal of the voltage regulator. A second Zener diode may be included having an anode coupled to the cathode of the first Zener diode and a cathode coupled to the first current electrode of the current control device.
A circuit is disclosed for improving operation of a linear regulator, having an input terminal, an output terminal, and a reference terminal. The circuit includes an input node, a transistor, a bias circuit, and first and second capacitors. The transistor has a first current electrode coupled to the input node, a second current electrode for coupling to the input terminal of the linear regulator, and a control electrode. The bias circuit has a first terminal for coupling to the output terminal of the linear regulator and a second terminal coupled to the control electrode of the transistor. The first capacitor is for coupling between the input and reference terminals of the linear regulator, and the second capacitor is for coupling between the output and reference terminals of the linear regulator. The bias circuit develops a voltage sufficient to drive the control terminal of the transistor and to operate the linear regulator. The bias circuit may be a battery, a bias device and a current source, a floating power supply, a charge pump, or any combination thereof. The transistor may be implemented as a BJT or FET or any other suitable current controlled device.



Power Supply: The examples chosen are taken from manufacturers' circuit diagrams and are usually simplified to emphasise the fundamental nature of the circuit. For each example the particular transistor properties that are exploited to achieve the desired performance are made clear. As a rough and ready classification the circuits are arranged in order of frequency: this part is devoted to circuits used at zero frequency, field frequency and audio frequencies. Series Regulator Circuit Portable television receivers are designed to operate from batteries (usually 12V car batteries) and from the a.c. mains. The receiver usually has an 11V supply line, and circuitry is required to ensure that the supply line is at this voltage whether the power source is a battery or the mains. The supply line also needs to have good regulation, i.e. a low output resistance, to ensure that the voltage remains constant in spite of variations in the mean current taken by some of the stages in the receiver. Fig. 1 shows a typical circuit of the power -supply arrangements. The mains transformer and bridge rectifier are designed to deliver about 16V. The battery can be assumed to give just over 12V. Both feed the regulator circuit Trl, Tr2, Tr3, which gives an 11V output and can be regarded as a three -stage direct -coupled amplifier. The first stage Tr 1 is required to give an output current proportional to the difference between two voltages, one being a constant voltage derived from the voltage reference diode D I (which is biased via R3 from the stabilised supply). The second voltage is obtained from a preset potential divider connected across the output of the unit, and is therefore a sample of the output voltage. In effect therefore Tr 1 compares the output voltage of the unit with a fixed voltage and gives an output current proportional to the difference between them. Clearly a field-effect transistor could do this, but the low input resistance of a bipolar transistor is no disadvantage and it can give a current output many times that of a field-effect transistor and is generally preferred therefore. The output current of the first stage is amplified by the two subsequent stages and then becomes the output current of the unit. Clearly therefore Tr2 and Tr3 should be current amplifiers and they normally take the form of emitter followers or common emitter stages (which have the same current gain). By adjusting the preset control we can alter the fraction of the output voltage' applied to the first stage and can thus set the output voltage of the unit at any desired value within a certain range. By making assumptions about the current gain of the transistors we can calculate the degree of regulation obtainable. For example, suppose the gain of Tr2 and Tr3 in cascade is 1,000, and that the current output demanded from the unit changes by 0.1A (for example due to the disconnection of part of the load). The corresponding change in Tr l's collector current is 0.1mA and, if the standing collector current of Tr 1 is 1mA, then its mutual conductance is approximately 4OmA/V and the base voltage must change by 2.5mV to bring about the required change in collector current. If the preset potential divider feeds one half of the output voltage to Tr l's base, then the change in output voltage must be 5mV. Thus an 0.1A change in output current brings about only 5mV change in output voltage: this represents an output resistance of only 0.0552.

Note the EHT selenium rectifier which is a Specially designed selenium rectifiers were once widely used as EHT rectifiers in television sets and photocopiers. A layer of selenium was applied to a sheet of soft iron foil, and thousands of tiny discs (typically 2mm diameter) were punched out of this and assembled as "stacks" inside ceramic tubes. Rectifiers capable of supplying tens of thousands of volts could be made this way. Their internal resistance was extremely high, but most EHT applications only required a few hundred microamps at most, so this was not normally an issue. With the development of inexpensive high voltage silicon rectifiers, this technology has fallen into disuse.

REX (Zanussi) RC120A CHASSIS BS201.4 CRT TUBE ITT (SEL) A31-19W

CRT TUBE ITT (SEL) A31-19W

HISTORY OF Standard Elektrik Lorenz AG IN GERMAN:

Die Standard Elektrik Lorenz AG (heute Alcatel-Lucent Deutschland AG) ist ein Unternehmen der Nachrichtentechnik (früherer Slogan: SEL – Die ganze Nachrichtentechnik) mit Hauptsitz in Stuttgart. Zur Nachrichtentechnik zählen auch Informations- und Kommunikationstechnik, Telekommunikationstechnik (SEL war für die Röchelschaltung bekannt) und früher Fernmeldetechnik oder Schwachstromtechnik. Einen weiteren Geschäftsbereich hatte das Unternehmen in der Bahnsicherungstechnik, so wurden für die Deutsche Bundesbahn Relaisstellwerke und elektronische Stellwerke mit den dazugehörigen Außenanlagen (Signale, Gleisfreimeldeanlagen, Weichenantriebe) sowie die Linienzugbeeinflussung entwickelt und gebaut, welche auch bei ausländischen Bahnen Abnehmer fanden. Der Bereich gehört seit 2007 als Thales Transportation Systems GmbH (seit 02.2011 vorher Thales Rail Signalling Solutions GmbH) zum Thales-Konzern. Die bereits 1998 ausgegliederten Bereiche Alcatel Air Navigation Systems und SEL Verteidigungssysteme sind ebenfalls heute in Thales Deutschland beheimatet.[1]
Fernseher Illustraphon 743 von 1957
„Goldsuper Stereo 20“ (1961)
Das Flaggschiff der erfolgreichen Schaub-Lorenz Kofferradios der sechziger Jahre: Touring 70 Universal
Erster Digitalfernseher der Welt (1983)

Bis 1987 gehörte SEL zusammen mit anderen auf dem Sektor Telekommunikation in anderen Ländern tätigen Schwesterfirmen zum US-amerikanischen Mischkonzern International Telephone and Telegraph (ITT). ITT verkaufte die Aktien-Mehrheit an den ITT-Telekommunikationsfirmen an die französische Compagnie Générale d’Electricité (CGE), die nach der Zusammenfassung mit den eigenen Telekommunikationsaktivitäten daraus die Alcatel N.V. bildete.

Die Standard Elektrik Lorenz AG wurde 1993 in Alcatel SEL AG umbenannt. Die Aktienmehrheit liegt mit über 99 % bei der Alcatel. Mit der Fusion von Alcatel und Lucent zu Alcatel-Lucent am 1. Dezember 2006 und der Neu-Firmierung beider Unternehmen in Deutschland zur Alcatel-Lucent Deutschland AG entfiel der Zusatz SEL.


Geschichte

Die beiden Stammfirmen des Unternehmens, die Mix & Genest AG und die Telegraphenbauanstalt von C. Lorenz, wurden 1879 bzw. 1880 gegründet. Das erste Patent von Mix & Genest datiert von 1883, das erste Patent von C. Lorenz ist aus dem Jahr 1902.

Das Unternehmen Mix & Genest war wesentlicher Teil der Standard Elektrizitäts-Gesellschaft (SEG), in die auch die Süddeutsche Apparatefabrik (SAF), die 1875 von F. Heller als "Friedrich Heller, Fabrik Elektrotechnischer Apparate" gegründet wurde, integriert wurde. Der technische Schwerpunkt von Mix & Genest bzw. SEG sowie der C. Lorenz AG war der klassischen Fernmelde- bzw. Funktechnik zuzuordnen. Die C. Lorenz AG baute in den 1920er und 1930er Jahren Großsender für den neu gegründeten Rundfunk.

1930 übernahm die International Telephone and Telegraph Company (ITT) die Aktienmehrheit der Mix & Genest AG und der C. Lorenz AG. [2]

Die C. Lorenz AG positionierte sich mit der Übernahme der G. Schaub Apparatebau-Gesellschaft mbH im Jahr 1940 in der Entwicklung und Herstellung von Rundfunkempfängern. Ab dem Jahr 1950 wurden alle Geräte bei Schaub in Pforzheim gefertigt. 1952 wurde das Typenprogramm beider Unternehmen verschmolzen und der Lorenz-Radio-Vertrieb in die Firma Schaub integriert. Ab 1955 wurden die Geräte unter dem Namen Schaub-Lorenz vertrieben.

1956 wurde das Unternehmen SEG in Standard Elektrik AG umbenannt. Ebenfalls 1956 wurde ein Kabelwerk gegründet. Wesentlicher Motor für das 1957 gegründete Informatikwerk war Karl Steinbuch, der von 1948–1958 dem Unternehmen, zuletzt als Technischer Direktor und Leiter der Zentralen Forschung, angehörte.

1958 erfolgte die Vereinigung der Standard Elektrik AG mit der C. Lorenz AG zur Standard Elektrik Lorenz AG (SEL).

Die Standard Elektrik Lorenz AG übernahm 1961 die Graetz KG. Die Firmenteile Schaub-Lorenz und Graetz waren zusammen mit einem Bildröhrenwerk Bestandteil der Unternehmensgruppe Audio Video der SEL AG, die 1979 als Audio-Video-Elektronik in die ITT ausgegliedert wurde. Die Produkte, die unter anderem Fernsehgeräte, Radios, Autoradios, Kassettenrecorder, Weltempfänger und Lautsprecherboxen umfassen, wurden fortan unter dem Namen ITT Schaub-Lorenz vertrieben.[2]

Versuche, auf dem neuen Gebiet der Raumfahrt-Elektronik Fuß zu fassen, waren auf folgende Produkte beschränkt:

* AZUR: Telemetrie/Telekommandogeräte
* Spacelab: Datenerfassung/Kommandoterminal.

SEL entwickelte zu Beginn der 1970er Jahre das Präzisionsanflugverfahren SETAC. Dieser Unternehmensbereich wurde im Jahre 1987 von der finnischen Firma Nokia übernommen.

1976 hatte SEL ein Grundkapital von 357 Mio. DM bei 33.000 Beschäftigten und einem Umsatz von 2,6 Mrd. DM.

1983 stellte SEL auf der Internationalen Funkausstellung Berlin 1983 mit dem ITT Digivision den weltweit ersten Fernseher mit digitaler Signalverarbeitung vor.[3]

2003 wurden die Markenrechte am Namen Schaub Lorenz an die italienische General Trading SpA verkauft. Die neugegründete Schaub Lorenz International GmbH vertreibt seitdem unter dem alten Markennamen Schaub-Lorenz importierte Konsumelektronik aus dem unteren Preisbereich.

NUCLEAR (PRANDONI) MOD. 531 YEAR 1977.

The NUCLEAR (PRANDONI) MOD. 531 portable 12" B/W television with
7 programs and potentiometers keyboard integrated tuning search system.
The mechanical turret approach to television tuning has been used almost exclusively for the past 60 years. Even though replete with the inherent disadvantages of mechanical complexity, unreliability and cost, such apparatus has been technically capable of performing its intended function and as a result the consumer has had to bear the burdens associated with the device. However, with the " recent "  Broadcast demands for parity of tuning for UHF and VHF channels, the increasing number of UHF and cable TV stations have imposed new tuning performance requirements which severely tax the capability of the mechanical turret tuner. Consequently, attempts are now being made to provide all electronic tuning to meet the new requirements.


The invention relates to a tuning unit with bandswitch for high frequency receivers, especially radio and television receivers, having a potentiometer system for the control of capacity diodes, the said potentiometer system consisting of a plurality of parallel resistance paths along which wiper contacts can be driven by means of screw spindles disposed adjacent one another in a common insulating material housing in which a bandswitch formed of metal rods is associated with each tuning spindle.
In these tuning units, the working voltages of the capacity diodes in the tuning circuits are recorded once a precise tuning to the desired frequency has been performed. A potentiometer tuning system has great advantages over the formerly used channel selectors operating with mechanically adjustable capacitors (tuning condensers) or mechanically adjustable inductances (variometers), mainly because it is not required to have such great precision in its tuning mechanism.
Tuning units with bandswitches formed of variable resistances and combined with interlocking pushbuttons controlling the supply of recorded working voltages to capacity diodes are known. Channel selection is accomplished by depressing the knobs, and the tuning or fine tuning are performed by turning the knobs. The resistances serving as voltage dividers in these tuning units are combined into a component unit such that they are in the form of a ladderlike pattern on a common insulating plate forming the cover of the housing in which the tuning spindles and wiper contacts corresponding to the variable resistances are housed. The number of resistances corresponds to the number of channels or frequencies which are to be recorded. The wiper contact picks up a voltage which, when applied to the capacity diodes determines their capacitance and hence the frequency of the corresponding oscillating circuit. The adjustment of the wipers is performed by turning the tuning spindle coupled to the tuning knob. By the depression of a button the electrical connection between a contact rod and a tuning spindle is brought about and thus the selected voltage is applied to the capacity diodes. Since the push buttons release one another, it is possible simply by depressing another button to tune to a different receiving frequency or a different channel, as the case may be.


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.


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.
It was possible to power it with mains or 12 volt source and it has even antennas for VHF and UHF channels.



TRANS CONTINENTS / OCEANIC / PRANDONI was an Italian manufacturer of radio and after of televison sets.

It was also the owner of brands like Trans Continents and Nuclear radio TV or simply Nuclear.

"Prandoni S.p.A." was founded by Dario Prandoni. Finally his son Giorgio Prandoni sold the company to the French "Thomson".

In 1998 Francesco Juilland and Giorgio Prandoni co-founded "Mediacube USA, Inc.", a film production company and a visual effects service provider in USA, Europe and in Italy.
a film production company and a visual effects service provider in USA, Europe and in Italy.

Giorgio Prandoni is a leading figure and heir to the most prestigious industrialist dynasty in the design and manufacture of radio equipment and multi standard television sets in Italy. (His father was Dario Prandoni the luminary owner of Prandoni S.p.A. one of Europe's most highly regarded electronic companies;


Dario Prandoni formed the basis of the Prandoni Empire and Giorgio Prandoni sells the company in France to Thomson with a big one deal). During his tenure from 1998 to February 2002 as Mediacube's CEO Francesco Juilland has created important joint venture between Mediacube USA, Inc. and important European, American and Canadian companies. He also brokered the acquisition of a share of Minerva Pictures (Italy) they own a library of more than 1,500 titles of which 850 are for worldwide rights in perpetuity. The titles include classics works by Pasolini, Germi, Bellocchio, Godard, Fellini, Antonioni and others. Most recently in 2000, Francesco Juilland was elected in the Board of Directors of Ionic WW Studios, a fully digital Hollywood studio organized and financed by Mediacube as Major Investor together with Giorgio Prandoni and Javier Rodriguez, Spanish businessman and scion of an important and conservative Family of Spain full of history and tradition and thank to the greenlight of a guardian angel like the economist Mr. Diego Colombo, chairman of the Colombo Group with offices in Switzerland and around the world and longtime serious advisor of the Juilland family office. Francesco Juilland is in the Board of Directors with the man that he considers his American mentor Mike Medavoy (producer, former chairman of Tristar Pictures and a legendary "Hollywood industry hero" as Fox News channel calls him, many times Oscars winner, his movies including the masterpieces Apocalypse Now, Philadelphia, Dance with wolves, Who flew over the Cuckoo's nest, Annie Hall, Platoon, Rocky, the Sting, Silence of the lambs, Amadeus, The Terminator, Sleepless in Seattle) and Norman Pattiz (called from "USA Today" and "LA Times" The Ted Turner of the radio) and Arnold Messer (president of Phoenix Pictures, company producer of Larry Flint, The thin red line, U-Turn, The 6th Day, Basic, Holes, Stealth, All the King's men), together with David Hayden and Gigi Pritzker (film producer with Deborah del Prete of "the Wedding Planner" with Jennifer Lopez)

Further Readings and Notes

^ Radiogrammofono PDRS 9 (PDF), in Selezione Radio, Anno I, nº 2, Febbraio 1950.
^ Brevetto per marchio d'impresa nr. 05875 del 1 febbraio 1952.
^ Baiocato, NRC 333 Radio Nuclear Radio Corporation; Cassano D'Adda MI,, su www.radiomuseum.org. URL consultato il 16 febbraio 2018.
^ Carlo Grimaldi, Tutto a transitors (PDF), in Informazione industriale, 1967.
^ Guidi, Stereo-Matic Hi-Fi 75 R-Player Prandoni SPA; TREVIGLIO BG, b, su www.radiomuseum.org. URL consultato il 16 febbraio 2018.
^ La Prandoni ritorna in attivo (PDF), in Selezione di tecnica Radio TV, Settembre 1982, p. 6.

External links for further information

• Alcune pubblicità degli anni 40-50
• Informazione industriale del 1967
• Fondo Prandoni in Lombardia Beni Culturali
• Principali apparati Prandoni

NUCLEAR (PRANDONI) MOD. 531 CHASSIS A40-73 INTERNAL VIEW.

All parts of the receiver are fitted on one board exept the TUNER and the POWER SUPPLY TRANSFORMER which are on the bottom of the cabinet.

The CHASSIS TECHNOLOGY is based on ASIC'S which are:TCA511 TBA311A17 TBA120SQ TAA611B12 and lots of discretes. Power supply is delivered after rectifiing via Transistor stabiliser. The set can be power supplyed via a 12Volt source in a socket on the rear of the lid.

Power supply is realized with mains transformer and Linear transistorized power supply stabilizer, A DC power supply apparatus includes a rectifier circuit which rectifies an input commercial AC voltage. The rectifier output voltage is smoothed in a smoothing capacitor. Voltage stabilization is provided in the stabilizing circuits by the use of Zener diode circuits to provide biasing to control the collector-emitter paths of respective transistors.A linear regulator circuit according to an embodiment of the present invention has an input node receiving an unregulated voltage and an output node providing a regulated voltage. The linear regulator circuit includes a voltage regulator, a bias circuit, and a current control device.

In one embodiment, the current control device is implemented as an NPN bipolar junction transistor (BJT) having a collector electrode forming the input node of the linear regulator circuit, an emitter electrode coupled to the input of the voltage regulator, and a base electrode coupled to the second terminal of the bias circuit. A first capacitor may be coupled between the input and reference terminals of the voltage regulator and a second capacitor may be coupled between the output and reference terminals of the voltage regulator. The voltage regulator may be implemented as known to those skilled in the art, such as an LDO or non-LDO 3-terminal regulator or the like.
The bias circuit may include a bias device and a current source. The bias device has a first terminal coupled to the output terminal of the voltage regulator and a second terminal coupled to the control electrode of the current control device. The current source has an input coupled to the first current electrode of the current control device and an output coupled to the second terminal of the bias device. A capacitor may be coupled between the first and second terminals of the bias device.
In the bias device and current source embodiment, the bias device may be implemented as a Zener diode, one or more diodes coupled in series, at least one light emitting diode, or any other bias device which develops sufficient voltage while receiving current from the current source. The current source may be implemented with a PNP BJT having its collector electrode coupled to the second terminal of the bias device, at least one first resistor having a first end coupled to the emitter electrode of the PNP BJT and a second end, a Zener diode and a second resistor. The Zener diode has an anode coupled to the base electrode of the PNP BJT and a cathode coupled to the second end of the first resistor. The second resistor has a first end coupled to the anode of the Zener diode and a second end coupled to the reference terminal of the voltage regulator. A second Zener diode may be included having an anode coupled to the cathode of the first Zener diode and a cathode coupled to the first current electrode of the current control device.
A circuit is disclosed for improving operation of a linear regulator, having an input terminal, an output terminal, and a reference terminal. The circuit includes an input node, a transistor, a bias circuit, and first and second capacitors. The transistor has a first current electrode coupled to the input node, a second current electrode for coupling to the input terminal of the linear regulator, and a control electrode. The bias circuit has a first terminal for coupling to the output terminal of the linear regulator and a second terminal coupled to the control electrode of the transistor. The first capacitor is for coupling between the input and reference terminals of the linear regulator, and the second capacitor is for coupling between the output and reference terminals of the linear regulator. The bias circuit develops a voltage sufficient to drive the control terminal of the transistor and to operate the linear regulator. The bias circuit may be a battery, a bias device and a current source, a floating power supply, a charge pump, or any combination thereof. The transistor may be implemented as a BJT or FET or any other suitable current controlled device.



Power Supply: The examples chosen are taken from manufacturers' circuit diagrams and are usually simplified to emphasise the fundamental nature of the circuit. For each example the particular transistor properties that are exploited to achieve the desired performance are made clear. As a rough and ready classification the circuits are arranged in order of frequency: this part is devoted to circuits used at zero frequency, field frequency and audio frequencies. Series Regulator Circuit Portable television receivers are designed to operate from batteries (usually 12V car batteries) and from the a.c. mains. The receiver usually has an 11V supply line, and circuitry is required to ensure that the supply line is at this voltage whether the power source is a battery or the mains. The supply line also needs to have good regulation, i.e. a low output resistance, to ensure that the voltage remains constant in spite of variations in the mean current taken by some of the stages in the receiver. Fig. 1 shows a typical circuit of the power -supply arrangements. The mains transformer and bridge rectifier are designed to deliver about 16V. The battery can be assumed to give just over 12V. Both feed the regulator circuit Trl, Tr2, Tr3, which gives an 11V output and can be regarded as a three -stage direct -coupled amplifier. The first stage Tr 1 is required to give an output current proportional to the difference between two voltages, one being a constant voltage derived from the voltage reference diode D I (which is biased via R3 from the stabilised supply). The second voltage is obtained from a preset potential divider connected across the output of the unit, and is therefore a sample of the output voltage. In effect therefore Tr 1 compares the output voltage of the unit with a fixed voltage and gives an output current proportional to the difference between them. Clearly a field-effect transistor could do this, but the low input resistance of a bipolar transistor is no disadvantage and it can give a current output many times that of a field-effect transistor and is generally preferred therefore. The output current of the first stage is amplified by the two subsequent stages and then becomes the output current of the unit. Clearly therefore Tr2 and Tr3 should be current amplifiers and they normally take the form of emitter followers or common emitter stages (which have the same current gain). By adjusting the preset control we can alter the fraction of the output voltage' applied to the first stage and can thus set the output voltage of the unit at any desired value within a certain range. By making assumptions about the current gain of the transistors we can calculate the degree of regulation obtainable. For example, suppose the gain of Tr2 and Tr3 in cascade is 1,000, and that the current output demanded from the unit changes by 0.1A (for example due to the disconnection of part of the load). The corresponding change in Tr l's collector current is 0.1mA and, if the standing collector current of Tr 1 is 1mA, then its mutual conductance is approximately 4OmA/V and the base voltage must change by 2.5mV to bring about the required change in collector current. If the preset potential divider feeds one half of the output voltage to Tr l's base, then the change in output voltage must be 5mV. Thus an 0.1A change in output current brings about only 5mV change in output voltage: this represents an output resistance of only 0.0552.

TAA611-A12 - Dual BTL power audio amplifier

TCA 511 TV HORIZONTAL AND VERTICAL PROCESSOR

The TCA 511 is a silicon monolithic integrated circuit in a 16—lead dual in—line plastic
package. It incorporates the following functions: high stability horizontal oscillator,
horizontal APC circuit with high noise immunity and large pull—in range, high stability
vertical oscillator and sawtooth generator.
lt is intended for driving TV horizontal and vertical transistorized output stages.








APPLICATION INFORMATION

Power Supply
The circuit can work with stabilized supply voltage having a value from 9 to 15 V.
A dropping resistor and a filter capacitor may be used to obtain the suipply from higher
voltages; however, the voltage on pins 3 and 4 must never exceed the maximum
permitted voltage.
Synchronization
Pins 2 and 6 can be DC driven if the reference level of the synchronization pulses is
less than 1 V. With reference levels greater than this value, a coupling capacitor must
be inserted in series with the input, and pins 2

and 6 must be connected to ground
via a resistor.
Vertical Oscillator
The capacitor connected to pin 1 must be selected with regard to the frequency
tolerance, to the thermal stability and to the capacitor's ageing.
The width of the output pulse, to be chosen according to the needs of the output
stages, is defined by the resistor connected between pin 1 and pin 16.
Vertical Output
The vertical output is taken from pin 14, which is a buffered output of the sawtooth
voltage generated at pin 15.
The output current from pin 14 is defined by an internal resistor in the integrated
circuit. if a greater current is needed, a resistor may be connected between pin 14
and pin 3.
The oscillator output pulse is available at pin 15 if the capacitor C9 is not connected. _
This configuration is used for driving output stages in which the sawtooth is generated
by Miller effect.
Horizontal Oscillator
The capacitor connected between pin 10 and ground must be selected with regard
to the frequency tolerance, 1:0 the thermal stability and to the capacit0r’s ageing.
In multistandard receivers, the oscillation frequency may be changed by switching the
value of the capacitor connected to pin 10.



GENERAL BASIC TRANSISTOR LINE OUTPUT STAGE OPERATION:

The basic essentials of a transistor line output stage are shown in Fig. 1(a). They comprise: a line output transformer which provides the d.c. feed to the line output transistor and serves mainly to generate the high -voltage pulse from which the e.h.t. is derived, and also in practice other supplies for various sections of the receiver; the line output transistor and its parallel efficiency diode which form a bidirectional switch; a tuning capacitor which resonates with the line output transformer primary winding and the scan coils to determine the flyback time; and the scan coils, with a series capacitor which provides a d.c. block and also serves to provide slight integration of the deflection current to compensate for the scan distortion that would otherwise be present due to the use of flat screen, wide deflection angle c.r.t.s. This basic circuit is widely used in small -screen portable receivers with little elaboration - some use a pnp output transistor however, with its collector connected to chassis.

Circuit Variations:
Variations to the basic circuit commonly found include: transposition of the scan coils and the correction capacitor; connection of the line output transformer primary winding and its e.h.t. overwinding in series; connection of the deflection components to a tap on the transformer to obtain correct matching of the components and conditions in the stage; use of a boost diode which operates in identical manner to the arrangement used in valve line output stages, thereby increasing the effective supply to the stage; omission of the efficiency diode where the stage is operated from an h.t. line, the collector -base junction of the line output transistor then providing the efficiency diode action without, in doing so, producing scan distortion; addition of inductors to provide linearity and width adjustment; use of a pair of series -connected line output transistors in some large -screen colour chassis; and in colour sets the addition of line convergence circuitry which is normally connected in series between the line scan coils and chassis. These variations on the basic circuit do not alter the basic mode of operation however.

Resonance
The most important fact to appreciate about the circuit is that when the transistor and diode are cut off during the flyback period - when the beam is being rapidly returned from the right-hand side of the screen to the left-hand side the tuning capacitor together with the scan coils and the primary winding of the line output transformer form a parallel resonant circuit: the equivalent circuit is shown in Fig. 1(b). The line output transformer primary winding and the tuning capacitor as drawn in Fig. 1(a) may look like a series tuned circuit, but from the signal point of view the end of the transformer primary winding connected to the power supply is earthy, giving the equivalent arrangement shown in Fig. 1(b).

The Flyback Period:
Since the operation of the circuit depends mainly upon what happens during the line flyback period, the simplest point at which to break into the scanning cycle is at the end of the forward scan, i.e. with the beam deflected to the right-hand side of the screen, see Fig. 2. At this point the line output transistor is suddenly switched off by the squarewave drive applied to its base. Prior to this action a linearly increasing current has been flowing in the line output transformer primary winding and the scan coils, and as a result magnetic fields have been built up around these components. When the transistor is switched off these fields collapse, maintaining a flow of current which rapidly decays to zero and returns the beam to the centre of the screen. This flow of current charges the tuning capacitor, and the voltage at A rises to a high positive value - of the order of 1- 2k V in large -screen sets, 200V in the case of mains/battery portable sets. The energy in the circuit is now stored in the tuning capacitor which next discharges, reversing the flow of current in the circuit with the result that the beam is rapidly deflected to the left-hand side of the screen - see Fig. 3. When the tuning capacitor has discharged, the voltage at A has fallen to zero and the circuit energy is once more stored in the form of magnetic fields around the inductive components. One half -cycle of oscillation has occurred, and the flyback is complete.

Energy Recovery:
First Part of Forward Scan The circuit then tries to continue the cycle of oscillation, i.e. the magnetic fields again collapse, maintaining a current flow which this time would charge the tuning capacitor negatively (upper plate). When the voltage at A reaches about -0.6V however the efficiency diode becomes forward biased and switches on. This damps the circuit, preventing further oscillation, but the magnetic fields continue to collapse and in doing so produce a linearly decaying current flow which provides the first part of the forward scan, the beam returning towards the centre of the screen - see Fig. 4. The diode shorts out the tuning capacitor but the scan correction capacitor charges during this period, its right-hand plate becoming positive with respect to its left-hand plate, i.e. point A. Completion of Forward Scan When the current falls to zero, the diode will switch off. Shortly before this state of affairs is reached however the transistor is switched on. In practice this is usually about a third of the way through the scan. The squarewave applied to its base drives it rapidly to saturation, clamping the voltage at point A at a small positive value - the collector emitter saturation voltage of the transistor. Current now flows via the transistor and the primary winding of the line output transformer, the scan correction capacitor discharges, and the resultant flow of current in the line scan coils drives the beam to the right-hand side of the screen see Fig. 5.

Efficiency:
The transistor is then cut off again, to give the flyback, and the cycle of events recurs. The efficiency of the circuit is high since there is negligible resistance present. Energy is fed into the circuit in the form of the magnetic fields that build up when the output transistor is switched on. This action connects the line output transformer primary winding across the supply, and as a result a linearly increasing current flows through it. Since the width is
dependent on the supply voltage, this must be stabilised.

Harmonic Tuning:
There is another oscillatory action in the circuit during the flyback period. The considerable leakage inductance between the primary and the e.h.t. windings of the line output transformer, and the appreciable self -capacitance present, form a tuned circuit which is shocked into oscillation by the flyback pulse. Unless this oscillation is controlled, it will continue into and modulate the scan. The technique used to overcome this effect is to tune the leakage inductance and the associated capacitance to an odd harmonic of the line flyback oscillation frequency. By doing this the oscillatory actions present at the beginning of the scan cancel. Either third or fifth harmonic tuning is used. Third harmonic tuning also has the effect of increasing the amplitude of the e.h.t. pulse, and is generally used where a half -wave e.h.t. rectifier is employed. Fifth harmonic tuning results in a flat-topped e.h.t. pulse, giving improved e.h.t. regulation, and is generally used where an e.h.t. tripler is employed to produce the e.h.t. The tuning is mainly built into the line output transformer, though an external variable inductance is commonly found in colour chassis so that the tuning can be adjusted. With a following post I will go into the subject of modern TV line timebases in greater detail with other models and technology shown here at  Obsolete Technology Tellye !

NUCLEAR (PRANDONI) MOD. 531 CHASSIS  A40-73 B-W TELEVISION DIAGRAM AND DEFLECTION CIRCUIT:

A unidirectional conductive device is coupled from a base terminal to a collector terminal of a horizontal deflection output transistor in a television receiver and poled in a direction to prevent the transistor from saturating when it is driven into its conductive state during a portion of each deflection cycle. Biasing means is coupled to the diode to preselect the desired operating voltage of the transistor during its conduction period.

1. In a television receiver, a deflection circuit comprising: 2. A circuit as defined in claim 1 wherein said transformer is an auto-transformer and said second terminal is intermediate said first and 3. In a television receiver, a deflection circuit comprising:

Description:

The present invention relates to transistorized deflection circuits utilized in television receivers.

In present day transistor deflection circuits, for example, those used in the horizontal output stage of a television receiver; the output transistor is normally operated in a switching mode, that is, the transistor is driven into saturation during a trace interval of each deflection cycle and driven out of conduction during the retrace portion of each deflection cycle. By operating the transistor in its saturation region, average power losses are minimized. With saturated operation, however, the accumulation of minority carriers in the base region will effect a continuation in the flow of collector current after the trace interval during the initial portion of the retrace interval while the transistor is being driven into its non-conducting state. In addition to causing this undesirable delay time in turning off the transistor, losses occurring during this period may be localized in small areas commonly referred to as "hot spots." These losses are characterized in being regenerative and tend to cause second breakdown of the device. This effect is explained in greater detail in a paper authored by the present inventor and entitled "Thermal Regeneration in Power Dissipating Elements" which appeared in "The Electronic Engineer" publication in the January 1967 issue. Although operating the horizontal output transistor in its saturated region may reduce the average power dissipated in this device during its conduction interval, it increases the possibility of second breakdown during the turn-off time. With the advent of high voltage (1,500 volts) transistors, it is possible to develop the necessary output energy utilizing one of these transistors which can be operated in a non-saturated mode. The circuit of the present invention insures that the deflection output transistor will not be driven into saturation.

Certain low power transistor switching circuits, such as employed in computer applications, have utilized diodes in conjunction with resistive biasing means coupled between the base and collector terminals to prevent the transistor from saturating and thereby increase the maximum switching frequency of the circuit by reducing the turn-off time of the device.

In the solid state deflection art, however, it is desirable to reduce the turn-off time of the device not to increase the frequency of operation of the circuit, but rather to prevent second breakdown of the device as the relatively large inductive voltage pulse appears during the initial portion of the flyback interval, when current flowing through the deflection winding is interrupted to initiate the retrace portion of each deflection cycle.

The non-saturated operation of the deflection output transistor is achieved in circuits embodying the present invention by automatically holding the collector voltage above the saturation level by shunting excess base drive from the base to emitter junction into the collector circuit. Prior transistor deflection systems employ only the saturated operation of the deflection output device.

Circuits embodying the present invention include a deflection output transistor having a diode coupled between its base and collector terminals and poled to prevent the transistor from being driven into saturation during its conduction period of each deflection cycle.

The invention can be more fully understood by referring to the drawings together with the description below and the accompanying claims.

In the drawings:

FIG. 1 illustrates in block and schematic diagram form, a television receiver including a solid state deflection output stage embodying the present invention;

FIG. 2a is a waveform diagram of the voltage present at the collector terminal 55c of transistor 55 in FIG. 1;

FIG. 2b shows the drive current to terminal A in FIG. 1;

FIG. 2c is a waveform diagram of the current in diode 56 in FIG. 1;

FIG. 2d is a waveform diagram of the base current flowing in transistor 55 of FIG. 1;

FIG. 3 is a schematic diagram of an alternative embodiment of the present invention;

FIG. 4a is a waveform diagram of the voltage appearing at the terminal 366 in FIG. 3;

FIG. 4b is a waveform diagram of the drive current to terminal A in FIG. 3;

FIG. 4c is a waveform diagram of the current in diode 356 in FIG. 3; and

FIG. 4d is a waveform diagram of the base drive current to transistor 355 in FIG. 3.

Referring specifically to FIG. 1, an antenna 10 receives television signals and couples these signals to a tuner 12 which selects the desired radio frequency signals of a predetermined broadcast channel, amplifies these signals, and converts the amplified radio frequency signals to a lower intermediate frequency (I.F.). The tuner 12 is coupled to an I.F. amplifier 14 which amplifies the intermediate frequency signals. The I.F. amplifier 14 is coupled to a video detector 16 which derives video information from the I.F. signals. The video detector 16 is coupled to a video driver stage 18 which amplifies the video signals. The video driver stage 18 is coupled to a video output stage 20, an automatic gain control stage 25 and a synchronizing separator stage 42. An output signal from video driver stage 18 may also be coupled to a sound channel (not shown) to reproduce the audio portion of the transmitted television program. The video output stage 20 couples amplified video information to a control element, such as a cathode 28, of a kinescope 30.

The automatic gain control stage 25 operates in a conventional manner to provide gain control signals which are applied to a radio frequency amplifier included in tuner 12 and to the I.F. amplifier 14. Sync separator 42 separates the synchronization information from the video information and also separates the horizontal synchronizing information for the vertical synchronizing information. The vertical synchronizing pulses derived from sync separator 42 are applied to the vertical deflection system 44 which provides the required deflection current to a vertical deflection winding 43 associated with kinescope 30 by means of the interconnection Y--Y. The horizontal synchronizing pulses from sync separator 42 are applied to an automatic frequency control detector 45 which serves to synchronize a horizontal oscillator 46 with the horizontal synchronizing pulses. The horizontal oscillator stage 46 is coupled to a horizontal driver stage 48 which develops the required drive signal and may be coupled by means of an output transformer in stage 48 (not shown) to a transistorized horizontal output stage 50. The transformer secondary, coupled to terminal A, provides a direct current path for the drive current.

The horizontal output stage 50 includes an output transistor 55 having a base, a collector and an emitter terminal 55b, 55c and 55e, respectively. A resistor 52 and a capacitor 53 are coupled in parallel between the horizontal driver stage 48 and the base terminal 55b of transistor 55.

The output stage includes a unidirectional conductive device such as a diode 56 coupled between the base and collector terminals 55b and 55c of transistor 55. Stage 50 also includes a damper diode 57 coupled across transistor 55, a retrace capacitor 58 coupled across transistor 55 and the series combination of a horizontal deflection winding 59 and an S-shaping capacitor 60 also coupled across transistor 55. Output stage 50 also includes a flyback transformer 61 with a primary winding 61p coupled from a source of operating potential (B+) to the collector terminal 55c of transistor 55. A secondary winding 61s on transformer 61 develops high voltage pulses which are coupled to a high voltage rectifier 63 to provide the ultor voltage for application to a terminal 32 on kinescope 30. Flyback transformer 61 may also include additional windings (not shown) for providing, for example, keying pulses to the AGC stage 25.

The output stage 50 in FIG. 1 is a conventional shunt fed trace driven circuit with the exception of the diode 56 and the bias network including resistor 52 and capacitor 53. Beginning at the center of the trace interval of the deflection cycle, the yoke current is zero and capacitor 60 has a maximum charge. The drive signal applied to the base terminal 55b of transistor 55 turns this device on, thereby completing the conduction path for yoke current which includes capacitor 60, yoke 59 and the collector to emitter current path through transistor 55. During this portion of scan the yoke current is supplied by the charge on capacitor 60 and increases to a maximum value in one direction at which time scan retrace is initiated by driving transistor 55 out of conduction by applying an appropriate signal from the driver stage 48 to the base 55b of transistor 55. During the latter portion of the trace interval when the magnitude of the yoke current is increasing, the output transistor of prior circuits is normally driven into saturation and is in this conduction state at the instant retrace is initiated. During the first portion of retrace, the yoke current is at a maximum and resonates with the retrace capacitor 58 by charging capacitor 58 in a polarity to reverse bias the damper diode 57. As the yoke current decreases to zero, capacitor 58 has a maximum charge impressed upon it; and during the second portion of retrace, the capacitor (58) drives current through the yoke in a reverse direction until it is discharged and the voltage across it reverses sufficiently to forward bias damper diode 57. Diode 57 then conducts during this first portion of trace to complete the current path for yoke current which is, at this instant, at a maximum value in a direction in yoke 59 to charge capacitor 60 and is increasing toward zero. At the mid-point of trace the yoke current has reached zero and the cycle is completed by driving transistor 55 into conduction once again.

Turning now to the operation of the circuitry of FIG. 1 including the present invention, reference is made to the waveform diagrams of FIG. 2. The initial portion of trace is represented in FIG. 2 by the time period between t ₀ and t ₁ in the figure. It is recalled that during this period damper diode 57 is conducting. The voltage at collector terminal 55c of transistor 55 is represented by the voltage waveform (V _c ) in FIG. 2a and is equal to the forward voltage drop across diode 57 which is of the order of -0.7 volts. At some non-critical time before t ₁ , the horizontal driver 48 provides a drive current (I _A ), as is shown in FIG. 2b. This current flows through diode 56 as is illustrated in FIG. 2c, since the diode is forward biased. [The cathode of diode 56 is at the same voltage as collector terminal 55c (-0.07 volts) and the drive current produces a positive voltage at point A which is at the anode of diode 56.] As time t ₁ (the center of trace) is reached, damper diode 57 turns off allowing the collector voltage on transistor 55 to increase as shown in FIG. 2a. At the same time, a portion of the drive current flowing into terminal A is conducted by the now forward biased base to emitter junction of transistor 55 as is illustrated by the waveform of FIG. 2d. Transistor 55 is now conducting the increasing yoke current during the latter portion of scan represented by the period from t ₁ to t ₂ in FIG. 2. As the magnitude of the yoke current increases during the t ₁ to t ₂ interval, the base current in transistor 55 increases as shown in FIG. 2d. Diode 56 conducts as illustrated in FIG. 2c to shunt the remaining portion of the applied drive current at terminal A. It is noted that the sum of the currents shown in FIGS. 2c and 2d will equal the current shown in FIG. 2b. The values of resistor 52 and capacitor 53 can be selected to hold the transistor collector voltage at a preselected value sufficient to prevent saturation of the transistor 55. If, for example, the voltage across capacitor 53 is 5.3 volts, the voltage at terminal A with respect to ground will be approximately 6 volts (5.3 volts plus the forward voltage drop across the base-emitter junction of transistor 55). The collector voltage will then be approximately equal to the voltage at terminal A less the forward voltage drop across diode 56. It is desirable to choose values of resistor 52 and capacitor 53 to operate transistor 55 near but not into the saturation region of conduction during the latter portion of each trace interval.

At time t ₂ retrace is initiated by applying a relatively large negative drive signal as shown in FIG. 2b to the base terminal of transistor 55. During the retrace interval (t ₂ to t ₀ in FIG. 2), the collector voltage increases in a typical manner as illustrated in FIG. 2a. At time t ₀ the cycle is again repeated.

The circuit modification illustrated in FIG. 3 is another embodiment of the invention which reduces the change in voltage applied to the yoke 59 of FIG. 1 at time t ₁ . As shown in FIG. 2a, when diode 57 turns off and transistor 55 conducts, the voltage at the collector terminal 55c of transistor 55 changes by as much, for example, as 6 volts. This voltage change, which is coupled to the yoke 59, will vary the rate of change of yoke current during the center of trace and may, in certain circuits, cause an undesirable non-linearity in the scanning rate. As FIG. 4a illustrates, the circuit of FIG. 3 reduces this change in voltage at the mid-point of trace (t ₁ ).

Referring to FIG. 3, the circuit elements which correspond to those of FIG. 1 are prefaced by the numeral 3. In explaining FIG. 3, it is helpful to refer to the waveform diagrams of FIG. 4. Transformer 364 in FIG. 3 is a tightly coupled auto-transformer wherein the tap point 365 may be, for example, at the 5 percent point on the transformer. That is, the segment between terminals 365 and 366 contain 5 percent of the total number of windings on transformer 364. Transformer 364 may also include a secondary winding such as the high voltage winding which is not shown in the figure. In operation, as drive current is applied at sometime prior to t ₁ as is shown in FIG. 4b, damper diode 357 is conducting and the voltage at terminal 366 is therefore at approximately -0.7 volts. Drive current flowing into terminal A as represented in FIG. 4b will be conducted by diode 356 during this interval as indicated by the diode current waveform in FIG. 4c. At the middle portion of trace (t ₁ ), the damper diode turns off and voltage at terminal 366 is thereby allowed to go slightly positive (less than 0.7 volts). The collector voltage of transistor 355 is held at a value of approximately 5 volts (assuming, for example, the B+ voltage is equal to 100 volts and the collector is coupled to the tap 365 on transformer 364 at a 5 percent point). At this instant, the base to emitter junction will be forward biased and transistor 355 conducts. It is seen that the anode voltage of diode 356 is at approximately +0.7 volts and its cathode which is coupled to terminal 366 is at a less positive voltage. Diode 356 begins to conduct during the latter portion of trace as illustrated by the current waveform diagram shown in FIG. 4c.

During the latter portion of trace, the transistor tends to saturate and the collector voltage at terminal 355c tends to decrease. As this occurs, more current will flow from the B+ terminal through the upper portion of transformer 364. Due to the relatively tight coupling of the segments of transformer 364, terminal 366 experiences a decrease in voltage which controls the forward bias applied to diode 356 to shunt sufficient drive current to hold the transistor 355 out of saturation. The collector voltage of transistor 355 is thus held at some preselected value depending on the location of tap point 365 on transformer 364. Since transformer 364 is utilized, terminal 366 will remain at a low voltage during the latter portion of trace as shown in FIG. 4a, and diode 356 will be forward biased during the application of a positive drive signal to terminal A. As before, the base drive current will increase and diode 356 conduction will decrease generally as shown in FIGS. 4c and 4d during the latter portion of trace. At time t ₂ in FIG. 4, a negative drive pulse is applied to the circuit which initiates the retrace interval of the deflection cycle.

Although the specific embodiments of the invention are illustrated in the horizontal deflection output stage of a black and white television receiver, the invention has equal applicability to other deflection systems and may be utilized in a color television receiver.

TBA 311 TV SIGNAL PROCESSING CIRCUIT


The TBA 311 is a monolithic integrated circuit in a 16-lead clual in-line or quad in—Iine
plastic package. It is intended for use as signal processing circuit for black and
white and colour television sets.
The circuit is designed for receivers equipped with tubes or transistors in the deflection
and video output stages, and with PNP or NPN transistors in the tuner and NPN in
the IF amplifier.
Only signals with the negative modulation can be handled by the circuit. The circuit
is protected against short circuit between video output and GND. The TBA 311 includes:




0 VIDEO PREAMPLIFIER with EIMITTER FOLLOWER OUTPUT
0 GATED AGC for VIDEO» IF AMPLIFIER and TUNER
0 NOISE INVERTER CIRCUIT for GATING AGC and SYNC. PULSE SEPARATOR
o HORIZONTAL SYNC. PIULSE SEPARATOR
0 VERTICAL SYNC. PULSE SEPARATOR
0 BLANKING FACILITY for the VIDEO AMPLIFIER.

NUCLEAR (PRANDONI) MOD. 531 CHASSIS  A40-73 Tuning unit with bandswitch for high frequency receivers

Abstract:

A tuning unit with a bandswitch for high frequency receivers having a potentiometer system for the control of capacity diodes is disclosed. The potentiometer system includes a plurality of parallelly disposed resistance paths on which wipers can be moved by means of screw tuning spindles mounted beside one another in a common housing made of an insulating material. The bandswitch is formed of metal wires and is associated with each tuning spindle. The tuning spindles are joined for rotation with sleeves simultaneously forming the operating knobs which are carried in apertures in the front plate and each have a flange engaging the back side of the front plate about the apertures. The flange is slightly larger than the cross section of the apertures and tapers conically away from the back side of the front plate.

1. Tuning unit with bandswitch for high frequency receivers having potentiometer means for the control of capacity diodes composed of a plurality of parallelly disposed resistance paths on which wipers are moved by means of screw tuning spindle means mounted beside one another in a common housing of insulating material, bandswitch means formed of metal wires associated with each tuning spindle means, said tuning spindle means being joined for rotation with sleeve means simultaneously forming operating knobs which are borne in apertures in the front plate and each sleeve means having an axial flange surface engaging the back side of the front plate about one aperture therein, said flange surface being slightly larger than the cross section of the apertures and tapering conically away from the back side of the front plate.

2. Tuning unit of claim 1 wherein the sleeve means are joined telescopically and coaxially with the tuning spindle means, and the flange surface engages the back side of the front plate when the sleeve means are in the state wherein they are pulled out of the front plate.

3. Tuning unit of claim 1 wherein the ends of the tuning spindle means which are opposite the front plate have each an annular groove into which a spring bracket engages whose bent end is supported against the housing and which has two diametrically disposed spring arms having opposite spring curvature, the said spring arms in each case contacting the opposite axial walls of the groove.

4. Tuning unit of claim 3 wherein the spring bracket rests with its bent end against the housing and the spring arms additionally engage a bracket formed on the housing or an intermediate bracket formed in one piece with the connection soldering lugs.

5. Tuning unit of claim 3 wherein the spring bracket is formed in one piece with the connection soldering lugs and has spring arms curved both in the same direction which engage an axial wall of the annular groove in the spindle and the opposite axial wall rests against a housing wall.

6. Tuning unit of claim 1 wherein the pointers associated with each potentiometer means lie on the one hand in windows associated with each tuning spindle means in the front plate, and on the other hand are rotatably mounted with their ends opposite the front plate in pivot pins on the housing, and the guiding pin of the spindle nuts carried in a longitudinally displaceable manner on each tuning spindle is provided with a slit disposed parallel to the longitudinal axis of the tuning spindle and slides with its peripheral surface resiliently within the slide tract of the pointer.

7. Tuning unit of claim 1 wherein the bandswitches are formed each of a displaceable metal rod which is in working engagement with stationary metal rods common to all bandswitches of a tuning unit, contacting each of them individually.

8. Tuning unit of claim 7 wherein the metal rods are metal wires.

9. Tuning unit of claim 7 wherein the metal rods are stamped metal parts.

10. Tuning unit of claim 7 wherein levers of insulating material are placed on the front ends of the displaceable metal rods and extend through windows which are provided with detents and which are associated with each tuning spindle in the housing front plate, while the opposite ends are held fixedly in the rearward end of the housing, and the displaceable metal rods individually make contact with contact cams on the stationary metal rods, these cams being in an offset array corresponding to the detents in the windows, the corresponding rods extending parallel to the front plate and parallel to one another behind the front plate.

11. Tuning unit of claim 7 wherein insulating material bridges or insulating material slide pieces are inserted between the contact cams of two adjacent, stationary metal rods and within the free space between two such parallel metal rods.

12. Tuning unit of claim 7 wherein the displaceable metal rods have, in the vicinity of their mountings on the housing, an articulation in the form of a vertically disposed flat portion.

Description:

BACKGROUND

The invention relates to a tuning unit with bandswitch for high frequency receivers, especially radio and television receivers, having a potentiometer system for the control of capacity diodes, the said potentiometer system consisting of a plurality of parallel resistance paths along which wiper contacts can be driven by means of screw spindles disposed adjacent one another in a common insulating material housing in which a bandswitch formed of metal rods is associated with each tuning spindle.
In these tuning units, the working voltages of the capacity diodes in the tuning circuits are recorded once a precise tuning to the desired frequency has been performed. A potentiometer tuning system has great advantages over the formerly used channel selectors operating with mechanically adjustable capacitors (tuning condensers) or mechanically adjustable inductances (variometers), mainly because it is not required to have such great precision in its tuning mechanism.
Tuning units with bandswitches formed of variable resistances and combined with interlocking pushbuttons controlling the supply of recorded working voltages to capacity diodes are known. Channel selection is accomplished by depressing the knobs, and the tuning or fine tuning are performed by turning the knobs. The resistances serving as voltage dividers in these tuning units are combined into a component unit such that they are in the form of a ladderlike pattern on a common insulating plate forming the cover of the housing in which the tuning spindles and wiper contacts corresponding to the variable resistances are housed. The number of resistances corresponds to the number of channels or frequencies which are to be recorded. The wiper contact picks up a voltage which, when applied to the capacity diodes determines their capacitance and hence the frequency of the corresponding oscillating circuit. The adjustment of the wipers is performed by turning the tuning spindle coupled to the tuning knob. By the depression of a button the electrical connection between a contact rod and a tuning spindle is brought about and thus the selected voltage is applied to the capacity diodes. Since the push buttons release one another, it is possible simply by depressing another button to tune to a different receiving frequency or a different channel, as the case may be.
To permit the switching of a number of channels in a certain tuning range, bandswitches for a plurality of tuning ranges, such as UHF and VHF for example, are often provided in the tuning units described above. In the pushbutton tuning unit of the above-named type, the bandswitch consists of a printed circuit board which is fastened on the housing of the tuning unit, and a switch lever which is preset by means of the pushbutton by turning, and is operated by depressing the pushbutton while at the same time selecting the channel.
Where this combination of knobs and pushbuttons is not possible, the selection of the range is accomplished by means of an additional lever which can be set over to select the range.
However, since such tuning units require too many riveting operations when they are assembled, tuning units were later created in which the individual parts in the voltage divider and pushbutton housing were loosely inserted and/or held in place by projections, lugs, hooks or tabs of resilient plastic. In spite of these initial improvements, the bandswitch, especially the one associated with the tuning units, was still technically intricate and very expensive.
THE INVENTION
It is the object of the invention, therefore, to create an additionally improved and simplified tuning unit containing a bandswitch of simple, space-saving and reliably operating design.
In accordance with the invention, this object is accomplished in a tuning unit with bandswitch of the kind described in the beginning by joining the tuning spindles for rotation with sleeves simultaneously forming the control knobs, which are mounted in apertures in the front plate of the housing and have each a flange engaging the back of the front plate around the aperture, the said flange being slightly larger than the aperture and tapering conically away from the back of the front plate.

In further development, the sleeves can be joined telescopically for rotation with the tuning spindles, and the flange is able to engage the back side of the front plate when the sleeve is in the position in which it is drawn out of the front plate. The sleeves constructed in this manner, whose portions projecting from the apertures in the front plate form the control knobs for the tuning spindles, permit easy assembly of the tuning unit and at the same time assure positive co-rotation of sleeves and spindles. The sleeves can be pushed from the front side of the front plate through the apertures onto the clutch surfaces of the spindles, this inward pushing being easily accomplished on account of the taper, and the dropping out of the sleeve being prevented by the flange engaging the back of the front plate. If the control knobs project only slightly out of the front plate, they can be operated from the outside by inserting a tool into them. With the telescoping type of coupling, however, it is possible to draw the sleeves or control knobs further outwardly so that they can be rotated by hand without the use of tools.
To provide constant assurance of the axial fixation of the tuning spindles, the tuning spindle ends farthest from the front plate can each be provided with an annular groove engaged by a spring bracket whose one leg is supported against the housing and whose other leg is forked to form two spring arms, each bent in the opposite direction and each engaging one of the two opposite walls of the annular groove. The tuning spindles are secured against axial displacement by this construction of the invention alone, without the need for further measures. This facilitates the joining of the sleeves or control knobs to the tuning spindle, because in this case there is no need for precise axial fixation and extreme dimensional accuracy.

Furthermore, the indicators associated with each potentiometer can be mounted in windows in the front plate which are associated with each tuning spindle or tuning knob for visual indication at the front, the other extremities farthest from the front plate being mounted for pivoting on pins set in the housing; the guiding pin on the spindle nut that is driven longitudinally on each tuning spindle can be provided with a slit disposed parallel to the long axis of the tuning spindles and can slide within the indicator slide lever slot, with its surface resiliently engaging the walls of said slot.
In an especially advantageous embodiment, the tuning unit can have bandswitches each formed of a displaceable metal rod which is in contacting engagement individually with stationary metal rods which are common to all of the bandswitches of a tuning unit. It contrast to the bandswitches known hitherto, which as a rule consist of a printed circuit board with switchable contacts thereon, this frequency bandswitch of the invention is of great simplicity, can be manufactured simply and inexpensively, and at the same time is very reliable in operation.
The displaceable and stationary metal rods of the bandswitches can be formed of metal wires or they can be of stamped sheet metal. Also, in further expansion of the concept of the invention, the stationary metal rods thus formed can be all entirely alike and merely offset from one another, thereby further simplifying the manufacture and stocking thereof.
To permit connection also to audiovisual apparatus, one or more of the stationary metal rods can be divided electrically into at least two parts each.
In a special development of this concept, lugs of insulating material can be mounted on the front ends of the displaceable metal wires, these lugs extending through windows in the front plate of the housing which are associated with each tuning spindle and are provided with detents, while the opposite ends can be held fixedly at the rear end of the housing, and the displaceable metal wires can make contact with contact humps on the stationary metal wires, the humps being offset from one another to correspond to the detents in the windows, and the stationary metal wires extending in back of the front plate, parallel to the latter and parallel to one another.
To increase switching reliability, bridges or sliding pieces made of insulating material can be inserted between the contact humps of adjacent stationary wires within the free space between two such parallel lying metal wires.
To achieve easy displacement of the displaceable metal wires despite the fixed end mounting on the housing, the displaceable metal wires, in further embodiment of the invention, can have each an articulation adjacent their end mountings, in the form of a vertically disposed flattened portion. This flat permits the metal wires to be deflected horizontally against a weak spring bias.
DESCRIPTION OF THE DRAWING
As an example of the embodiment of the invention, there is represented in the drawings a tuning unit with bandswitch for television receivers. In these drawings,
FIG. 1 is a front elevational view of a tuning unit with bandswitch,
FIG. 2 is a plan view showing the bandswitch of the tuning unit of FIG. 1,
FIG. 3 is a side elevational, cross-sectional view of the tuning unit of FIG. 1,
FIG. 4 is a rear elevational view of the tuning unit of FIG. 1,
FIG. 5 is a plan view showing the indicator means of the tuning unit of FIG. 1,
FIG. 6 shows the sleeve with the operating knob and tuning spindle,
FIG. 7 shows the telescoping manner in which the sleeve is joined to the tuning spindle,
FIG. 8 is a fragmentary view of the bandswitch,
FIG. 9 is another fragmentary view of the bandswitch, and
FIG. 10 shows how the tuning spindle is fixed in position.
DESCRIPTION
The method of representation used in the drawings is greatly simplified, for the purpose of better delineating the features of the invention. The tuning unit with bandswitch consists of an insulating material housing 1 with a front plate 2, which is closed by a cover plate 3 accommodating the resistance paths. The housing 1 is divided by parallel sidewalls 4 into chambers in which the tuning spindles 5 are disposed.
The embodiments is an 8-fold tuning unit having eight bandswitches assocated with each tuning spindle, and eight indicators.
Accordingly, there are eight apertures 6 in a central row, through which the operating knobs 7 of the sleeves 8 coupled with the tuning spindles 5 are passed. The operating knobs 7 have recessed surfaces 9 for turning with a turning tool. In a row extending parallel above the row of the apertures 6 there are eight windows 10, whose upper edge is provided with notches 11. Lugs 12 of insulating material extend through the windows 10 and engage the upper notches 11 and are joined behind the front plate to displaceable metal wires 13 of the bandswitch. In a row located beneath the row of apertures 6 another eight windows 14 are provided, through which the ends of the pointers of the indicators 15 protrude.
Now, the bandswitch consists in each case of a displaceable metal wire 13 which can be brought into working engagement with stationary metal wires 16, which are all of the same construction and are only disposed offset from one another. While the displaceable metal wire 13 extends substantially parallel to the longitudinal axis and thus at right angles to the front plate 2, the stationary, parallelly disposed metal wires 16 are parallel to the front plate 2 and are thus inserted at a right angle to the displaceable metal wire. A departure from parallelism or from the right angle, as the case may be, takes place substantially only when the displaceable metal wire 13 is deflected to the two outer notches. The rearward end 18 of the displaceable metal wire, which forms a vertical loop, is tightly inserted into a receiver 17. Just ahead of the loop 18, the metal wire 13 is provided with a vertically disposed portion 19 by a flattening on the metal wire 13. The movement, when the metal wire 13 is deflected into the desired notches or detents, takes place horizontally by the flexing of these portions 19. The stationary metal wires 16 are held tightly in their positions in projections 20 on the housing, or by lugs or the like. Since three switch actions are provided, that is, three ranges, for each tuning spindle, a bandswitch consists of one displaceable metal wire and three stationary metal wires 16, which are used for all switches.
To permit each bandswitch to have exactly three switching actions, each of the three stationary metal wires 16 has one contact hump 21 corresponding to one of the detents 11 in the windows 10 of the front plate 2. The contact humps 21 are thus located one next to the other as seen from the front plate 2. So that the displaceable metal wire 13 will always come into mechanical and electrical contact only with the desired contact hump, and prevent short circuits, insulating bridges 22 are installed between the adjacent metal wires 16, said insulating bridges being stationary.
If more or less than three switching actions are desired, all that need be done in the case of the bandswitch of the invention is to change the number of stationary metal rods or wires accordingly.
The sleeves 8 with the operating knob 7 have a flange 23 engaging the back of the front plate 2 and tapering back to the point where it joins the tuning spindle. This enables the sleeves to be pushed in, in the case of a housing that has already been manufactured with the tuning spindle installed, without creating the possibility that the sleeves 8 might escape after they have been inserted. The sleeves 8 are connected to the tuning spindles 5 usually by means of driving surfaces. If manual operation without tools is to be possible, rather than requiring a tool for the operation of the sleeves, the coupling of the sleeve 8 to the tuning spindle will be a telescoping coupling (see FIG. 7).
The actual firm axial fixation of the tuning spindle 5 is located on the rear end of the housing. Here the tuning spindle 5 has an annular groove 24 which is engaged by a spring by means of two diametrically disposed spring arms 25 and 26. The spring arms 25 and 26 have oppositely curved lugs and are supported on the housing at their terminal and marginal surfaces and their lugs engage opposite axial walls 27 and 28 of the annular groove 24.
Additional support is provided by the common, bent foot 29 of the spring arms 25 and 26 against the cover plate of the housing.
The indicator means of the tuning unit with bandswitch consists of a pointer 15 which is movable within the window 14, and a cam 30 which is a prolongation of the pointer 15. At its rearward end, the pointer is mounted rotatably in the housing on pin 31. Within the cam 30 slides a guiding pin 32 which is attached to the spindle nut or carriage 40. Upon the rotation of the tuning spindle, the spindle nut is longitudinally displaceable therewith. In order to achieve good guidance and hence precise indication, the guiding pin has a slit 33 extending parallel to the longitudinal axis of the tuning spindle 5, so that it will resiliently engage the cam 30 within the slot thereof.
The necessary soldering lugs are indicated at 34.
On the basis of the design of the tuning unit with bandswitch in accordance with the invention, a desired frequency range--UHF, for example--can be selected by deflecting a displaceable metal wire 13 into one of the detents 11 by means of the lug 12 mounted thereon. Within this range, a transmitter or channel can then be selected by turning the tuning spindle 5. The transmitter preselected in this manner can then be tuned in by means of a keyboard or by electronic recall from a keyboard which is not shown. The fine tuning of this tuned-in transmitter, as well as the selection of a different transmitter within the same frequency range, is accomplished by turning the tuning spindle 5.
All of the details explained in the above description and represented in the drawings are important to the invention.

All circuits were made by:

SGS is Società Generale Semiconduttori - Aquila Tubi E Semiconduttori (SGS-ATES, "Semiconductor General Society - Tubes and Semiconductors Aquila"), later SGS Microelettronica, a former Italian company now merged into STMicroelectronics

SGS Microelettronica and Thomson Semiconducteurs were both long-established semiconductor companies. SGS Microelettronica originated in 1972 from a previous merger of two companies:

• ATES (Aquila Tubi e Semiconduttori), a vacuum tube and semiconductor maker headquartered in the Abruzzese city of l'Aquila, who in 1961 changed its name into Azienda Tecnica ed Elettronica del Sud and relocated its manufacturing plant in the outskirts of the Sicilian city of Catania
• Società Generale Semiconduttori (founded in 1957 by Adriano Olivetti).

The line deflection is using the AU110 A Germanium PNP TRANSISTOR, see below the datasheet:

AU110

Germanium PNP

Category: Germanium Transistor, PNP Transistor, Transistor
MHz: <1 MHz
Amps: 10A
Volts: 160V

Ge PNP Power BJT


V(BR)CEO (V)=160
V(BR)CBO (V)=160
I(C) Abs.(A) Collector Current=10
Absolute Max. Power Diss. (W)=30
I(CBO) Max. (A)=100u
h(FE) Min. Static Current Gain=20
h(FE) Max. Current gain.=90
@I(C) (A) (Test Condition)=1.0
@V(CE) (V) (Test Condition)=2.0
Package=TO-3
Military=N

- The EHT Output is realized with a selenium rectifier.

The EHT selenium rectifier which is a Specially designed selenium rectifiers were once widely used as EHT rectifiers in television sets and photocopiers. A layer of selenium was applied to a sheet of soft iron foil, and thousands of tiny discs (typically 2mm diameter) were punched out of this and assembled as "stacks" inside ceramic tubes. Rectifiers capable of supplying tens of thousands of volts could be made this way. Their internal resistance was extremely high, but most EHT applications only required a few hundred microamps at most, so this was not normally an issue. With the development of inexpensive high voltage silicon rectifiers, this technology has fallen into disuse.