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Gec dual standard mono TVs

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Till Eulenspiegel
(@till)
Posts: 4947
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Hi Jeffrey,
The 625 line IF amplifier unit which was made to convert certain Thorn 700 phase 2 and 800 series models. I'm certain that the 600 series models can be converted, although no system switch was fitted.
Did you convert your 606T to 625 only?

Till Eulenspiegel.

 
Posted : 29/01/2015 5:06 pm
colourstar
(@colourstar)
Posts: 632
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Here are some scans from service manuals that may assist the old memory banks tie appearances to model numbers -

Brilliant! I recognise all of those variants on the last scan and after all these years can now identify the jumble sale Sobell I referred to in my previous post as an 1102. I can also see the school classroom TV there too- the GEC 2084 but in an all-white cabinet.

Mystery solved on both counts. Thanks Graham!

Steve

 
Posted : 29/01/2015 5:10 pm
Rebel Rafter
(@rebel-rafter)
Posts: 184
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Hi again, RR here. That hand built IF unit reminds me of another similar unit that was fitted in the old thorn 700 series, I had one once, it was a big 23 inch console model which was basically 405 only but could be converted or upgraded to dual standard ready for the start of BBC2 in 1964. Part of the dropper had to be shorted out for the extra heaters. Also I remember an unusual feature of the 700 series, the speaker instead of being the more usual 3 ohm was about 40 ohm, a bit like those used in early transistor audio outputs but this one was a valve output stage with the usual transformer but with a higher than usual output impedance, I could never understand why. RR.

 
Posted : 29/01/2015 5:56 pm
Till Eulenspiegel
(@till)
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Wasn't interested in that old fashioned 405 at the time :)

I have confessed to same sin. In fact I was worse than that, I took the point of view 405 had to be done away with at all costs.

Getting back to the GEC dual standard sets. I mentioned The Sobell ST196DS-T which later became the model 1000 and GEC 2000.
A very early ST196 was available which had a 405 only signals board. The timebase was dual standard. I never came across a fully converted set.

Till Eulenspiegel.

 
Posted : 29/01/2015 10:38 pm
Focus Diode
(@focus)
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I had a McMichael MT763DS/T fully dual std model several years back, think the Sobell equivalent is the ST195 or ST196. The optional flywheel sync panel was never fitted, 625-lines resulted in a constant "ticking" sound from within. Line lock was incredible: with the IFs at 625 a 625 image on 405 locked perfectly with reduced width! I don't know of another d/s model employing a PY33 HT rectifier.

As for the 2014, I had a 2017 in 1978-81 which was styled indentically but coloured grey/green. This had VHF radio facilities, I'm not sure if it was supposed to do this but on selecting the radio channels the raster would slowly fade out, yet never completely with the line timebase (405-lines) functioning! Switching off resulted in a bright spot remaining on the screen. When switched back to TV the raster would slowly brighten up to normal. There was Sobell equivalent, the 1017. Don't think any examples have survived unfortunately.

Brian

 
Posted : 01/02/2015 4:56 pm
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