27 Dec
2006
27 Dec
'06
7:04 p.m.
Chris M wrote:
--- Brent Hilpert <hilpert at cs.ubc.ca> wrote:
Certain old TVs had a separate CRT heater supply that could be adjusted
up and down a bit. Also, one I remember (BRC 1400 chassis? Dead common
around here, whatever it was) had a resistor across the heater, to act
as a shunt. Thus the heater was actually rated for 150mA instead of the
300mA of the rest of the heater string, and you could drop out a link on
the shunt resistor to put a bit more through the heater.
Bodgetastic stuff. Oh, and of course there was the big tapped wirewound
with voltages printed on for anything from about 200v up to 260v - mains
could be very variable out in the sticks.
Gordon
The other trick in the old days was the picture
tube
booster, a small
autotransformer plugged in between the chassis
connector and the CRT to boost
the filament voltage and run the cathode hotter.
After the CRT deteriorated
further you might have it re-gunned.
I obtained a brand new one of these, probably
specific to a particular make/model, but don't ask me
which (it ain't in front of me). I had also heard that
there's something called an "age switch", but I have
to wonder if the guy was pulling my leg, cuz I never
found one. But possibly it employed a technique like this?