31 Jan
2006
31 Jan
'06
4:56 p.m.
On 1/31/2006 at 11:50 PM ard at p850ug1.demon.co.uk wrote:
Those were not common over here, possibly because 99.9%
of valved
monochrome TVs had a series chain of heaters which included the CRT.
That setup didn't manifest itself here until the 1960's. All 1950's sets
had very large (and desirable for other projects) power transformers. I
imagine that today the glass audio folks would really love to get some of
those old hunks of iron. Secondary winding was typically something like
450-0-450v rms, with several separate heater windings; usually 5v for the
rectifier (usually a 5U4) and 6.3v for most of the other bits and maybe an
extra winding for the horizontal output heater. It wasn't that uncommon
to re-wind the secondary for higher voltage and current for transmitter
use. A transformer from an old RCA color set was the golden ring--an
absolutely huge thing.
I spent many happy hours scavenging old TV chassis for parts, even after
the owners had removed all of the glass from them (with a thought toward
using them later, no doubt). The old 21 MHz IF turret-type tuners were
wonderful for VHF work.
Cheers,
Chuck