Found this interesting photo of a GEC set, any ex trade care to speculate the GEC model?
I can't remember the chassis number it was the last GEC model before they started fitting Hitachi chassis' It was 20AX with the panels in a frame around the tube neck a similar layout to the delta gun solid state model that proceeded it. It had a large chunky tuner drawer mounted vertically and recessed slider controls. It may have just been known as "the 20AX" chassis circa 1979 ish I think.. Very reliable ISTR.
Here's another, this time a teletext prototype receiver incorporated into the GEC 2121. Manufactured at GEC’s Hirst Research Centre.
Yet more period Viewdata adverts and another unknown TV
ITT had Prestel sets and the slider controls look very like ITT. Prestel training courses were run at the ITT facility in Farnworth Greater Manchester.
Was it C2233H?
Till Eulenspiegel.
The first Teletext models I saw were the ITT CVC30 with the big pull out ultrasonic remote control, the handset was larger with an extra row of buttons. 20AX tube. There were a few teletext delta gun sets but as with the GEC solid state that Chris has posted mainly prototypes. I saw a picture of a G8 with a wired TT keyboard, again a prototype.
The First Teletext sets I remember in any quantity was the ultrasonic remote G11 I think Teletext was slow to get going as it was expensive and seen as a bit of a gimmick . It was hard enough to talk buyers and renters into parting with the extra cash for remote control !
I saw a picture of a G8 with a wired TT keyboard, again a prototype.
There were a few G8's released with Teletext using the Texas Instruments 'TIFAX' board. The first G8 I saw had been hurriedly modified for an upcoming Philips trade show...that must have been 1976. As I recall, there were three boards involved, one above the other and I think a sizeable power supply board as well. Ultrasonic remote control. All that crammed into a G8. The later G9 had a model fitted with Teletext using the same boards. It was all rather primitive at the time with only a single page accessible at a time (no four page memory), you had to enter the page number by pressing 'P' first followed by the three digits and the graphics were non-contiguous (black gaps between different colours) although we thought it was pretty amazing. It didn't really start to get going until the G11 with the Philips chipset and refinements to the memory and the ability to reveal answers to quizzes etc.
Can’t remember which make of set but I know the early ones had the Texas chipset, I don’t know if these were complete Texas PCB’s or just the chipset .
Wasn't the Bush BC6333 one of the first teletext models to appear in the marketplace in 1976? The chassis was the Z718. The set employed the Tifax teletext decoder.
Getting back to the GEC teletext TV set model type might be C2236H. I remember buying three sets to find out the demand for such receivers. Trade price direct from the manufacturer was well over £300.00! According to the sales rep the best possible price of course, the big stores pay the same. All three sets finished up on rental so it took a long time to get my money back on the investment. The teletext decoder was the Mullard VM6101.
I know the TIFAX board was treated as a 'black box'. Any attempt at repair was strictly forbidden. I think the only thing we were allowed to touch was the power supply which wasn't Texas Instruments.
Most manufacturers produced at least one 20AX model fitted with the Texas TIFAX board. Bang and Olufsen 4402 had a factory fitted TI teletext option. As I recall the board proved to be very unreliable and with no spares available it had to be exchanged. Within a very short time even this was no longer an option and B&O produced a redesigned interface to allow the better performing Mullard - Philips board to be used as an in-service replacement.
When I went for a job interview with Rediffusion at their Chessington R&D office, I actually got to talk to the design engineer who was involved with the development of a Prestel interface for the Mk3. Interesting technology at the time, all a long time ago!
Rich
