Re: Toshiba high voltage problem

From: James Sweet (jamessweet_at_hotmail.com)
Date: 11/22/04 

Date: Mon, 22 Nov 2004 23:40:30 GMT

"Bobby Villamor" <bobbyv@shaw.ca> wrote in message
news:F1fod.301087$nl.261429@pd7tw3no...
> Hello everyone.
> I am working on a 27in. toshiba color tv model CF27G50. Original trouble
> symptom is that
> when I push the power button on, the relay clicks supplying power and I
> could hear the high
> voltage attempting to build up then just about a second the relay clicks
> turning the ac supply off.
> I have tried disconnecting each low voltage power loads to check which
> circuit or component
> causes the relay to turn off almost instantly until I reach the high
voltage
> section.
> When I turn the power button on I see some sparks in the picture tube
> electron gun - somewhere
> around the filament / cathode area, then the relay turns off.
> When I remove the high voltage cap from the picture tube the relay remains
> on already, high voltage
> is produced but the weird thing is that when I push the power button on
the
> pcb or attempt to touch
> any ground connection: wire, heat sink, etc., a high voltage arc jumps
from
> the ground to my
> finger before my finger touches it and I receive a mild electric shock.
> Looks like excessive high voltage? But why do arc jumps even when a ground
> terminal is touched?
> I tried connecting in parallel the two snubber capacitors - those
connected
> across h.o.t. with a
> capacitor of smaller value but no effect.
> I would appreciate any hint, comments or help regarding this problem.
> Thank you very much.
> Bobby
>
>

Usually sparks inside the CRT mean the tube has cracked and needs to be
replaced. Sometimes they crack under the yoke where you can't see it, I had
one I was checkihg out, I went to pull the neck board off and the whole neck
of the tube came off in my hand.