I doubt it's your transistor, as your monitor wouldn't have come back
from the dead after failing the first time. More likely you have a dry
joint in a hot part of the PCB, or an overheating elecrolytic. It might
be hard to find the problem area, but at least it'll be a lot easier &
cheaper to fix than a failed flyback transistor.
I had the chassis apart earlier this evening and went through the heat
sinks, tightening screws that hold the power devices to them. Some screws
were not snug, so I made them so. I also blew out some of the dust that had
accumulated on the flyback and HV wire. Reassembled cabinet and have been
running it for about 2 hours now. I'm waiting for it to reoccur.
It almost seemed like an arc problem, as the outage was usually accompanied
by an audible snap. I also made sure the HV wire didn't pass within 1/2" of
anything else by repositioning it a bit.
The odd part about this is that today is the first really cold day, our heat
has not been turned on yet, so it's chilly in the office, and the monitor
fails. Not last week when it was 77º in here.
I suspected a semiconductor because I have seen some types of semiconductors
go 'soft' and become temperature sensitive. I didn't have a can of
refrigerant spray handy, so I could not test my hunch with this one however.
The capacitors are also a candidate, as is the potential of solder problems.
Frankly, I hope I don't have to disassemble it that far. The solder side of
the PCB is, as you probably can imagine, only accessed once you've
COMPLETELY disassembled the chassis. That could take more than an hour. I
think it was 28 screws just to get the back cover and cage removed. I'll say
a prayer that it was either a loose screw or a dust problem causing arc and
current limit foldback.
Thanks for the suggestions.
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Take care,
Mark & Mary Ann Weiss
VIDEO PRODUCTION . FILM SCANNING . DVD MASTERING . AUDIO RESTORATION
Hear my Kurzweil Creations at:
http://www.dv-clips.com/theater.htm
Business sites at:
www.dv-clips.com
www.mwcomms.com
www.adventuresinanimemusic.com
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