The 2000 convergence board did indeed have locations for a transductor and associated components but were never fitted, the 3000 didn't have any provision for pincushion correction at all. Early GEC dual standards also had no pincushion fitted either and some Japanese and American sets I believe. As for blue gun down operation, that was a failure in "all weather testing" compounded by Paraffin and LPG powered heaters which were popular in the 70s. The Japs and others did produce CRTs for blue gun down but with the final anode at the top as used in the 17" 8000, maybe they knew of these problems and even today Paraffin/Kerosene heating is still around for domestic heating in Japan.
As to wether blue gun down makes a difference I would definitely say yes, my first CTV was a 2000 and I found the pincushion distortion unacceptable particularly at the top of the screen where a 3000 was less so. I'm sure I read in TV mag or somewhere that a survey of the general public was done and errors in the top quarter of picture were not picked up as much.
As for the rounded 22" A55-14X I suspect this CRT was mainly for the American market and brought over here as a stopgap until Mazda could produce the A56-120X. I saw a picture the other day of a large late console RCA model which was fitted with a Thomson chassis and the CRT wasn't push through but had a mask which accentuated rounder corners of old.
John.
I understand that the BBC used a monitor version of the 2000 chassis which did have the pincushion fitted.
@malcscott Pye, RBM, Thorn claimed from what I remember to have their early CTV’s in the BBC, whether monitor or standard sets. The BBC probably wanted to confirm what reception was like on the various brands.
One thing that puzzled me was RBM, the claimed very close cooperation with the BBC yet their first offering was the CTV25*, the picture on the ones I worked on were good but the Pye D/S using mainly Mullard derived circuits gave a much better picture, again this is subjective.
* The CTV25 did have the burning Bush reputation but that was something entirely different to the picture quality. I didn’t have that problem with the sets we had but I still retrofitted the Davy lamp mod just in case.
Frank
I wondered about that.
All the Thorn 3504s we saw in Oz had the EHT connector at the bottom, unlike all other TVs. We just assumed it was because they were made in the northern hemisphere!
I think I might have fitted a tube to one set the "right" way up out of curiousity. It made no difference at all.
I don't want to speak too soon but the set has now run for many hours without throwing up any more faults. So yesterday evening I have put the back on in readiness for it to go up to my workshop.
One thing I noticed is that the tube base panel isn't quite level, it is slightly leaning to the left. I checked the other set and the panel is level in that so it looks as if the re-gunner didn't get the gun quite in straight... If that is the case it is remarkable that the convergence is as good as it is!
All the Thorn 3504s we saw in Oz had the EHT connector at the bottom, unlike all other TVs. We just assumed it was because they were made in the northern hemisphere!
What the same as the moon? 😉
One thing that puzzled me was RBM, the claimed very close cooperation with the BBC
There's a difference between making sets to broadcast standards and to consumer standards though. There were RBM professional colour monitors in the BBC: I know someone who has at least one. Most manufacturers put their prototypes through the BBC as well: I know of an RBM 405 colour set.
Pye also had professional monitors, one of which earned the nickname of "the firebox". IIRC it was a failure of the series HT regulator that was the issue there.
