TV kits was Re: Tek 555 was Re: Need pointers on Oscilloscopes

[Jim Beacon]

From: "Tony Duell" <ard at p850ug1.demon.co.uk>
> > Did they every have a DIY for B&W TV like they
> > had for radios the begining years of development?
>
> Oh yes. I don't know how far back you want to go, but there were
> certainly mechancially-scanned TV kits.
>
> After the war in the UK, there were several designs using ex-radar CRTs.
> OK, you got a green-and-black picture, but it was a lot cheaper to use
> govenrment suprlus than new componets (and those EF50s from the radar
> sets came in handy too ;-)). I can't eememember if the 'Viewmaster' was
> on such, or if that used a CRT designed for televison, but it was
> certainly a home-built TV. Practical Televison magazine (later to become
> simply 'Television') publisehed a number of homebrew TV designs over the
> years, including at least one colour set.
>
> -tony

There were, as Tony says, a number of kits and self build designs available
in the years just before and just after WW2. I have a design for a Radar
tube based set on my bench at the moment, as I'm planning to modify it into
a multi standard monitor (240, 405, 441, 625) for use with a PC based
standards converter experiment (we already have it producing video at  240,
405, 525 and 625 line standards, and should be able to push it to 819 lines
as well). The design is for the video and timebase sections only, using a
VCR97 as the display, with all other valves being EF50 (SP41 or SP61 are the
recommended alternatives, all common as government surplus in the 50's),
except the video clamp, which is EA90. In the original, the RF stages were
taken from a "GEE" receiver (it had a 45Mc/s IF strip which became a TRF
video receiver), and one of the plug-in GEE RF units was converted to a TRF
sound receiver.

Going back further, the Baird 30 line mechanical system became popular after
the "Daily Express" newspaper produced and distributed "televisor" kits -
somewhere I have a picture of them loading railway trucks with the kits.
There were also other suppliers of kits and specialist components, like
Nipkow discs, or mirror screws.

Cossor produced a kit for a 405 line set, and there were others. Caseless
chassis, with and without CRT and valves were also offered in the 50's, and
I believe at least one homebuild colour set was based around a readily
available chroma panel from a commercial set.

Jim.