4 Jan
2007
4 Jan
'07
12:36 p.m.
It;s is a lot easier to isolate a VHF or UHF signal (a couple of special
capacitors will do it) than baseband video/audio (which would involve
spectial transformers or opto-isolators at least). I've seen a few
top-end (B&) and the like) valved TVs (live chassis, of ocurse) which had
a special audio transformer to provide an isolated (from the mains) audio
output from the set to feed into a tape recorder or whatever. But it
wasn't common at all.
-tony
Very common here also (chassis live) till mid 1990's then changed to
isolation via the flyback transformer, partial hot chassis till
flyback transformer. Then SMPS for isolation. Some do double
isolation via SMPS then flyback transformer.
Still, certain area of chassis (just a one board now) even on SMPS is
hot.
Isolation transformer is a MUST when servicing any even brand new
set. No buts or ifs.
Cheers, Wizard