Nigel Goodwin wrote:

> >Barry, the two-thyristor scheme was used extensively for horizontal
> >deflection and HV circuits before HV transistors were available. Try to
> >get hold of a Grundig color TV set schematic from about 10-15 years ago.
> >Maybe Roman has one. It's a neat scheme. Of course the theory is discussed
> >in contemporary application notes (from ITT and others).
>
> As someone who has been repairing TV's for over 30 years I have to
> disagree with that statement. Thyristor line output stages were
> extremely rare, only a very small number of manufacturers used them
> (Grundig was one of them) - most TV's were using transistor line output
> stages years before the twin thyristor circuit. The UK Thorn (Ferguson,
> HMV, Ultra etc.) company (long since defunct!) produced the worlds first
> all transistor colour TV around 1968/69, the 2000 series - a dual
> standard 405/625 receiver. At that time all other sets (including
> Grundig) made extensive used of valves (tubes!).
>
> We are actually a Grundig agent, their two thyristor design didn't
> appear until 4 or 5 generations of Thorn all transistor sets had been
> available. Most other UK manufacturers had also switched to transistors
> by that time.


Hi Nigel, I have quite a few thyristors here,
I think they were used in the vertical stage
of the old Sony Trinitrons TVs?? Its been over
10 years since I last remember needing one for
for something, but I can't remember what. :o)
-Roman

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