re: WG6100 heat problem

From: <wboucher6_at_cogeco.ca>
Date: Tue Apr 03 2012 - 13:23:52 EDT

Unfortunately, there are several things that could cause Q606 to be stuck turned on. I'll assume that Q606 is in fact
good and not leaking like crazy. Be aware that it might operate/test okay when cool and go into thermal runaway once it
warms up enough. In that case, you'd also get a picture for a while and I assume you are not.

Faults that will cause your described condition:
- an open diode at D600, D601, or D602
- an open R611
- an open Q603
- a shorted Q601
- opens at any of R602, R604, Q602, R605

Bill Boucher
http://www.biltronix.com

>
> Been fixing 6100's for some time and this is the first time I have run
> into this issue. I have a monitor that was brought to me with the
> following problem. Q606 is getting extremely hot. So hot that the
> transistor socket is turning black like burnt toast and the frame is
> almost too hot to handle on the right hand side.
>
> Believe it or not, the transistor is still working. I have been through
> the deflection board several times and found nothing. I did find both
> power transistors bad so replaced those and the blown fuses and the
> socket on Q606 and it still will not come up. I only spent a few
> minutes on it as I had to leave town for business. I'm just curious
> what would cause the transistor to get so blasted hot.
>
> I will be getting back to it on Saturday to troubleshoot some more.
>
> Pat
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Received on Tue Apr 3 13:24:02 2012

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