Possibly stupid question?

[andy]

...

[colin4014]

Originally Posted by andy

I would be interested in hearing more about the Thorn 2000. I've always read that the Motorola Quasar was the world's first production solid state color TV, but American publications tend to ignore foreign accomplishments (particularly in the late 60's when the US was at the center of the universe).

The 2000 chassis was introduced in 1967 and was fully SS except for the CRT, the US set you are talking about had a glass rectifier valve.

The 2000 had development problems when it came to the HV side if things, The best and newest transistors (from the US) were expensive at $15.00. a shot and in development thorn were blowing out many hundreds a day - until the got the circuits perfected! It was a very popular set at the launch, so-so picture but a world beater (according to the press of the time).

I will try to dig out some of the original paperwork and publish it, but this interesting site gives an insight to the Thorn 2000 chassis and all the different models produced. Plus some of the other makers sets of that period.http://www.oldtechnology.net/colour.html

[old_tv_nut]

Originally Posted by colin4014

The 2000 chassis was introduced in 1967 and was fully SS except for the CRT, the US set you are talking about had a glass rectifier valve.

What sort of high voltage rectifier was used, do you know? When I joined Motorola in 1966 they were working on the solid state chassis (I wasn't directly involved), and they used a single solid state rectifier assembly that consisted of a stack of several hundred "high" voltage rated diodes (perhaps 1kv each). The asembly had curved side fins to equalize the capacitive current among the diodes from the top to the bottom of the stack. The units were made by Varo in Texas.

I don't know how long Motorola used tube rectifiers, but my impression is that it was just a stopgap while the solid state rectifiers were being perfected.

[colin4014]

Originally Posted by old_tv_nut

What sort of high voltage rectifier was used, do you know? When I joined Motorola in 1966 they were working on the solid state chassis (I wasn't directly involved), and they used a single solid state rectifier assembly that consisted of a stack of several hundred "high" voltage rated diodes (perhaps 1kv each). The asembly had curved side fins to equalize the capacitive current among the diodes from the top to the bottom of the stack. The units were made by Varo in Texas.

I don't know how long Motorola used tube rectifiers, but my impression is that it was just a stopgap while the solid state rectifiers were being perfected.

Off hand I have no idea, and I will have to get the service manuals out of storage. The Christmas holiday has become rather extended in the UK and for most non-retail operations extend thru to the 3rd January! That includes my storage facility.

I spent an hour or two reading through my dads Journals this morning and I am learning some interesting things about some interesting Anglo/USA connections. In 1955 Thorn and Sylvania set up a CRT plant in the UK, in 1956 they formed the Sylvania Thorn colour TV labs here. and before 1967 Thorn were importing the Glass CRT bulbs from the USA for the original run of CTV tubes and building them here. Dad also mentions co-operation between Thorn and RCA in the mid 60s (have not found out what for as yet).
Those Line output / EHT state of the art transistors were Texas R2009.

No round tube CTVs were ever marketed in the UK as by 1967 rectangular tubes were the norm here, BUT dad did say that it is possible that some rebranded USA round tube sets were actually imported, modified for PAL UHF 625 line 240 volt 50 hz.. and put on the rental market?

[andy]

...