GBC MOD.?? YEAR 1966.

The GBC MOD.?? (I don't know model code) is a 19 inches B/W Television with VHF and UHF Rotary Tuners.

Television receivers currently being manufactured for consumer use were capable of operation in either the VHF (very high frequency) or UHF (ultra high frequency) bands of frequencies. In order to provide this capability, however, it is necessary to include two separate tuners or tuning circuits in the television receiver with one of these circuits being utilized for VHF reception and the other being used for UHF reception. The VHF tuner conventionally is a turret type of tuner having 13 detented positions which accomplish the coarse tuning or channel selection of the VHF tuner and a separate control is provided to effect the fine tuning at each of the channel positions. Generally, mechanical channel selecting devices for VHF television tuners fall into two groups, namely, the rotary-switching type or the turret types. Turret type tuners include an incrementally rotatable channel selector shaft for selectively connecting certain ones of a plurality of tuned circuit elements to each of a plurality of channel selector positions. UHF tuners generally employ a separate control mechanism or a tuning knob and use a dial indicator of a type commonly found in manual radio receivers. UHF tuners for television receivers are usually of a continuous tuning type similar to the tuning system adapted for radio sets. Therefore, the tuning in UHF channels has been extremely difficult as compared to the tuning in VHF channels. Such continuous tuning systems for the UHF tuners has heretofore been sufficient, since only two or three UHF channels have been authorized in one locality. However, where more UHF channels, namely seven or eight channels, are available for reception, a non-continuous type UHF tuner, which enables simpler tuning operation, is desired. Nevertheless, this continuous tuning system has heretofore been satisfactory, because there were only 2 or 3 UHF band channels or stations available for reception in an area. However, where there are an increased number (7 or 8 or more, for instance) of UHF band channels or stations available for reception, a non-continuous or intermittent tuning system as is adopted for the VHF tuner is preferable.

More desirably, the fine tuning control is presettable, so that the desired channel may be readily selected by merely turning the main channel switch-over shaft. The use of two separate tuning control mechanisms in order to effect the VHF and UHF tuning of the receiver is  at best; and when a receiver is provided with remote control capabilities, generally only the VHF band of frequencies may be remote controlled and the UHF channels still must be selected manually at the receiving set location.Conventional turret tuners still leave room for improvement, especially as far as minimizing the tuner size and dimension, and simplifying the assembly, as well as lowering the manufacture costs and improving the tuner performance are concerned.

The set is based all around tubes exception for the UHF tuner which features AF139 transistors.


GBC is a commercial brand with a long tradition and solid experience. It history begins in 1958, when Gian Bruto Castelfranchi (G.B.C.) established the company, with the aim of conquer the market.GBC is the acronym for Gian Bruto Castelfranchi, who founded the company in 1958 in order to commercialize instrument accessories and related material.
It is his son Jacopo, however, who made GBC the biggest company in Italy for the commercialisation of electronic materials and devices.

Jacopo joins his father's company in 1946, starting to increase the number of represented products and expanding in the field of electronic components, tubes, passive components and various equipment such as tape recorders and turntables.

The company expands and diversifies and in 1957 the Selezione di Tecnica Radio TV periodical is born, for which is created the J.C.E., Jacopo Castelfranchi Editore who was also the editor of a monthly
 Magazine "IL CINESCOPIO" with his technical director Amadio Gozzi.

Not to be confused with the Selezione Radio magazine, published from 1951.

In 1962 the head office is transferred to Cinisello Balsamo owing to a shortage of space.
In 1970, the magazine changes its name to Sperimentare Selezione di Tecnica Radio TV.
In 1970 it becomes a Sony distributor for Italy and it later creates a joint venture with it.
The sales points in Italy reach maximum expansion with over 150 shops.
GBC also designs and creates its own high-fidelity stereo systems and televisions.
In these years, GBC also commercialises assembly kits branded “High kit” and “Amtron”.
In the next few years, it also becomes an importer for Bang&Olufsen, Sinclair and Goldstar.
GBC is sold in 1980.



With these words we could define Kon.El.Co. S.p.A. The history of the society in fact is recent, but the competence and the experience baggage that this company is able to guarantee, defines this reality as a reliable distributor with a long commercial tradition. Founded in 1994, Kon.El.Co. S.p.A. developed immediately, earning the concession of well-known commercial brands. Subsequently the company has become a S.p.A. and since then has obtained great results, always more and more rewarding, that today define Kon.El.Co. S.p.A. as one of the leader society in the electronic branch. Since the beginning, GBC brand accompanies the success of Kon.El.Co. S.p.A., constituting the most important commercial project of the company.

A good point  on good  old  B/W Televisions.....................

The Sixties was a time of great change for TV. At the start of the decade there were just monochrome sets with valves, designed for 405 -line transmissions at VHF. By the end there was 625 -line colour at UHF, with transistorised chassis that used the odd IC.

The following decade was one of growth. The "space race" had begun in 1957, when the USSR launched Sputnik 1 and terrified the Americans. Thereafter the USA began to spend countless billions of dollars on space missions. This got underway in earnest in the Sixties, with the announcement that America would be going all out to get a man on the moon by the end of the decade. There followed the Mercury series of earth - orbit missions, then the Apollo launches. Success was achieved in 1969. Most of these missions were televised, and in those days anything to do with space was hot stuff. It was inevitable that everyone wanted to have a television set. At the time an average receiver would be a monochrome one with a 14in. tube - there was no colour until 1967. It would cost about 75 guineas. 
TV sets were often priced in guineas (21 shillings) as it made the price look a bit easier on the pocket. Anyway 75 guineas, equivalent to about £78.75 in 2000's currency, was a lot of money then.  For those who couldn't, rental was a good option. The Sixties was a period of tremendous growth for rental TV. 
Much else was rented at that time, even radios, also washing machines, spin driers, refrigerators and, later on, audio tape recorders (no VCRs then). 
For most people these things were too expensive for cash purchase. 
There were no credit cards then. And when it came to a TV set, the question of reli- ability had to be taken into account: renting took care of repair costs. 

TV reliability.........The TV sets of the period were notoriously unreliable. They still used valves, which meant that a large amount of heat was generated. The dropper resistor contributed to this: it was used mainly as a series device to reduce the mains voltage to the level required to power the valve heaters. These were generally connected in series, so the heater volt- ages of all the valves were added together and the total was subtracted from the mains voltage. The difference was the voltage across the heater section of the dropper resistor, whose value was determined by simple application of Ohm's Law. 
As valves are voltage -operated devices, there was no need to stabilise the current. So the power supply circuits in TV sets were very simple. They often consisted of nothing more than a dropper resistor, a half or biphase rectifier and a couple of smoothing capacitors. If a TV set had a transformer and a full wave rectifier in addition to the other components, it was sophisticated!
 As the valve heaters were connected in series they were like Christmas -tree lights: should one fail they all went out and the TV set ceased to function. Another common problem with valves is the cathode -to -heater short. When this fault occurs in a valve, some of the heaters in the chain would go out and some would stay on. Those that stayed on would glow like search- lights, often becoming damaged as a result. Dropper failure could cause loss of HT (dead set with the heaters glowing), or no heater supply with HT present. When the HT rectifier valve went low emission, there was low EHT, a small picture and poor performance all round. CRTs would go soft or low emission, the result being a faint picture, or cathode -to -heater short-circuit, the result this time being uncontrollable brightness. On average a TV set would have twelve to fourteen valves, any one of which could go low -emission or fail in some other way. All valves have a finite life, so each one would probably have to be replaced at one time or another. The amount of heat generated in an average TV set would dry out the capacitors, which then failed. So you can see why people rented! 

The CRT could cause various problems. Because of its cost, it was the gen- eral practice to place its heater at the earthy end of the chain. In this position it was less likely to be overloaded by a heater chain fault. But during the winter months, when the mains voltage dropped a bit, it would be starved of power. This would eventually lead to 'cathode poi- soning' with loss of emission. The 'cure' for this was to fit a booster transformer designed to overrun the heater by 10, 20 or 30 per cent. It would work fine for a while, until the CRT completely expired. At about this time CRT reactivators came into being - and a weird and wonderful collection of devices they turned out to be. Regunned tubes also started to appear. You couldn't do this with the `hard -glass' triode tubes made by Emitron. These were fitted in a number of older sets. Yes, they were still around, at least during the early Sixties.



Developments................... A great deal of development occurred during the Sixties. Many TV sets and radios made in the early Sixties were still hard -wired: the introduction of the printed circuit board changed the construction of electronic equipment forever. The first one was in a Pam transistor radio. PCBs were ideal for use in transistor radios, because of the small size of the components used and the fact that such radios ran almost cold. 
They were not so good for use with valve circuitry, as the heat from the valves caused all sorts of problems. Print cracks could develop if a board became warped. If it became carbonised there could be serious leakage and tracking problems. In addition it was more difficult to remove components from a PCB. Many technicians at that time didn't like PCBs. As the Sixties progressed, transistors took over more and more in TV sets. They first appeared in a rather random fashion, for example in the sync separator stages in some Pye models. Then the IF strip became transistorised. Early transistors were based on the use of germanium, which was far from ideal. 

The change to silicon produced devices that were more robust and had a better signal-to-noise ratio. 
Car radios became fully transistorised, and 'solid-state' circuitry ceased to be based on earlier valve arrangements. Many hi-fi amplifiers had been transistorised from the late Fifties, and all tape recorders were now solid-state. 
Both reel-to-reel and compact -cassette recorders were available at this time. Initially, audio cassette recorders had a maximum upper frequency response of only about 9kHz. 
To increase it meant either a smaller head gap or a faster speed. Philips, which developed the compact audio cassette and holds the patents for the design (which we still use in 2000!) wouldn't allow an increase in speed. Good reel-to-reel recorders had a fre- quency response that extended to 20kHz when the tape speed was 15in./sec. 
This is true hi-fi. In time the frequency response of compact -cassette recorders did improve, because of the use of better head materials with a smaller gap. 
This led to the demise of the reel-to-reel audio recorder as a domestic product We began to benefit from spin-offs of the space race between the USA and the USSR. 
The need to squeeze as much technology as possible into the early computers in the Mercury space capsules used by the USA lead to the first inte- grated circuits. 
This technology soon found its way into consumer equipment. Often these devices were hybrid encap- sulations rather than true chips, but they did improve reliability and saved space. The few chips around in those days were analogue devices.  To start with most UHF tuners used valves such as the PC86 and PC88. They were all manually tuned. Some had slow-motion drives and others had push -buttons. They didn't have a lot of gain, so it was important to have an adequate aerial and use low -loss cable..............................