"Is that capacitor leaking...

...or is it just glad to see me?"

I ripped into the JVC XP-A1000BK this morning, and what I found was not altogether surprising.

There are four 4700µF caps in the power supply. As you remember (from last week's episode), this unit had had a previous problem with what appeared to be a malformed cap. After a long period of disuse, it didn't work until the cap was allowed to reform (by letting the unit run for an extended period). This time, it stops operating after a minute or so, and "recovers" after a few hours.

When I found the power-supply section (it's "hidden" on the digital converter board), I noticed dried brown liquid at the bases of all four caps. (No, it's not adhesive.) Whoops. They might not be the cause of this problem, but they definitely need replacing. All these caps are Elnas. (No Necchis.) They're around 20 years old.

Looking at the solder side, it appears that most of the power-supply electrolytics have been replaced. This unit has never been in for service -- it was a reviewer's sample, which now appears to have been a "rework".

Anyhow, when the unit is "dead", the +12V, -12V, and +40V supplies are okay. But the +5V supply is caput.

So I'll replace the leaking caps, plus the +5V regulator and most of the stuff around it. That should fix it.


Reply to
William Sommerwerck
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