GEC Hybrid Colour

[toshiba tony]

Hello All,
Just stepping back in time. We used to renovate this model in the 70\80's. And belters they were too, We couldn't supply enough, OK. they had a few stock problems and some of the newer engineers struggled with dual print, but on the whole I like them. Memory vague but some sets didn't have the PY500 (boost diode). How was scan recovery executed, was it a solid state version? Thanks anyone.
Tony Walker

[Nuvistor]

Was it the PY500 that was missing or the PD500 shunt stabiliser? I thought they used a tripler with 5th harmonic tuning and a PL509/PY500.
Could be completely wrong of course after all this time.

[FERNSEH]

Very early production GEC 2040 series single standard hybrid CTVs employed a silicon diode as the boost diode, can't remember the full type designation of the device, BY
In later production models the silicon diode was replaced by a PY500 valve.
The first dual standard GEC CTVs employed a Mullard LP1174 EHT tripler module and the EHT stabilisation was effected by a voltage dependent resistor.
No nasty X-ray generating tubes in these sets.
I'm presently working on my GEC 2028. The set was bought in 1968 and was in continual use until 1979 when it was replaced by a Toshiba C2080B.
The GEC hybrid colour TVs were reliable, much better than some other early CTVs I could mention.

DFWB.

[Nuvistor]

Thanks for that info David, I knew there was something about no PD500.

[FERNSEH]

Hi Frank,
I think there is a GEC 2040 series service manual in the shop. When it's found I can determine the type number of the solid state boost diode, unless someone else beats me to it, that is.
The pictures are of the chassis of my GEC 2028. It's being assessed to find out if it is possible to return the chassis back to full dual standard operation. The system switches were removed in the late seventies.

DFWB.

[FERNSEH]

GEC 2040 series, early version: D53 boost diode was a BY147P.

DFWB.

[toshiba tony]

Thanks all, sorry, forgot to say it was the single standard (2040?) The reference to the PD500 threw me further. But at least you have come to my aid AGAIN. Thanks all

[toshiba tony]

Whilst you kind posters have rejuvenated my memories of the 2040 one thing remains obscure. Due to "top cap activity", was any shielding in place around the anode of the solid state rectifier? I can't recall ever seeing a set with this diode in use. now a picture, wow, I'd kill for. Was in the trade in the days of TV125's and Thorn850's but this GEC model eludes me. Thanks anyone.

[Nuvistor]

Hi Tony,
Service info for the 2040, see post 11.
https://www.vintage-radio.net/forum/...ad.php?t=72431

[Peter.N.]

I solved the double sided print problem by applying the soldering iron to the top of the board, this held the print down while you pulled out the component.

Peter

[Welsh Anorak]

Hi
EHT rectification was by a tripler. The solid state rectifier mentioned above was the boost diode, usually a PY500(A). I only vaguely recall ever seeing one. Obviously not a great success and confined to the very early 2040 sets. I imagine if the boost capacitor shorted then the solid state diode would die immediately unlike the valve.
The dual standard 2028 used a conventional PY500/PL505(9) arrangement, so goodness knows why they took this step.
Returning the 2028 to full dual working looks a difficult task - were you thinking of using relays or finding slide switches from somewhere - possibly an old GEC mono set?
I was always surprised by complaints about the double sided print. I used Peter's method above with no problems.
The last versions of the hybrids were great sets and streets ahead of the solid state ones that replaced them with their horrible plastic cabinets. I looked after one that went through three 20" tubes!

[FERNSEH]

Originally Posted by Welsh Anorak

Returning the 2028 to full dual working looks a difficult task - were you thinking of using relays or finding slide switches from somewhere - possibly an old GEC mono set?

Hi Glyn, I've given up on that idea, instead I'm on the lookout for a complete 2028,2029 or 2030 dual standard chassis.
I do have a pair of switches which were removed from scrap Ekco TV receivers that had FM radio. The intention was to fit those in the GEC 2028 but it turns out these will never be a satisfactory replacement for the original system switches.

DFWB.

[FERNSEH]

The attachment shows the Ekco TV/FM switches which I intended to fit in the GEC 2028.
One switch was removed from a wrecked TMB282 and the other is a NOS item.

DFWB.

[McMurdo]

Didn't rediffusion rent these?

[FERNSEH]

"Didn't Rediffusion rent these?"
Hi Kevin,
I believe so. Radio Rentals offered a Baird branded version of the GEC 2028, the model 705.

See attachment.

DFWB.

[mark_in_manc]

Assuming that's from about 1968, it makes colour rental about 11 hundred quid a year in today's money. Wow - I hadn't appreciated what big business it was (born 1970).

[FERNSEH]

Originally Posted by mark_in_manc

Assuming that's from about 1968, it makes colour rental about 11 hundred quid a year in today's money. Wow - I hadn't appreciated what big business it was (born 1970).

It was 1968. Twenty-five shillings = £1.25p Fifty-two weeks X 1.25 is £65.00.
The retail price of a GEC 2028 was £259 including purchase tax. No idea what RR paid GEC for the sets, let's say £175, it might have been less. Taking all the companies' expenses into account it'll take four years to realise a profit.

DFWB.

[Peter.N.]

I had a number of 2028s and 2040s out on rental in the '70s and '80s, I paid about £60 each mostly from John Carter in Nottingham and latterly Ilkeston. I rented them out at £10.00 per month or sold them with a 12 month guarantee for £110.00.

By the mid '80s I had about 150 GEC rentals although by this time they were the Granada PIL tube version. I carried a box of panels in the car and could repair most sets in situ in about 15 minuets. The only job I didn't like was changing the tripler, got my hands dirty.

Peter

[FERNSEH]

At 24 inches long and 11 inches deep the chassis of the GEC 2028 could be considered a compact unit, for 1967 that is.

DFWB.

[Vintage Engr]

Originally Posted by McMurdo

Didn't rediffusion rent these?

Yes they did, I worked for them. Fairly reliable, but horrible early double-sided print, that did cause problems for engineers who were'nt careful with the non-temperature controlled soldering irons of the day!

Dave.