Re: TECH Q: W-G deflection PCB in Space Duel

From: <jwelser_at_ccwf.cc.utexas.edu>
Date: Thu Oct 22 1998 - 11:07:09 EDT

On Thu, 22 Oct 1998 solarfox@texas.net wrote:

> The burnt component is R100, which turns out to be part of the
> low-voltage supply. A quick check with a VOM confirms that Q100 is
> completely shorted across both junctions...
>
> Question: is this just a random failure, or is there something else in
> the system which might _cause_ this - and thus, cause it to happen again
> once I replace the bad components in the low-voltage section - that I
> should be sure to check? (I've already tested the obvious culprits, like
> the deflection and power transistors; none of them appear to be shorted
> internally or to the chassis...)
>

        It's probably just Q100, but check all the other semis in the
LV power supply, especially the zener diodes.

        Q100 fails "fairly" often -- not as often as Q101...

Joe
Received on Thu Oct 22 10:07:12 1998

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