Re: Help diagnosing problem.

From: James MacPhail <gg__at_email.domain.hidden>
Date: Wed, 07 May 2008 02:17:20 -0700

>What is the easiest way to test Q5 and U1, and I do not have a whole lot
>of equipment just a multimeter.

Q5: If your meter has a "diode test" function, you can do an in-circuit check that there is a diode-like junction between the collector and emitter. ie. about 0.5 volt drop in one direction, open circuit the other. A short circuit would indicate Q5 may be bad. If you remove it from the board, you would check that the b-c and b-e junctions are diode-like and that c-e is not shorted.

The slight corrosion around the mounting bolt doesn't look like a problem in your picture.

U1: I agree with the previous suggestion of measuring its DC output voltage to ground.

NB: In addition to the shock hazard already mentioned in this thread, there is an implosion hazard. The neck of the CRT is fragile, and when knocked or bumped, it can break. Since the CRT contains a vacuum, the result is shards of flying glass. One should wear safety glasses and gloves, and have someone nearby to assist in case of an accident. Proceed at your own risk.

Good luck!


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. Received on 2015-07-15 16:43:15

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