Electronics > Repair
Mastech HY5020E 50v 20a Bench Supply: Economical to repair?
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MrSlack:
Watch out for the cheap Chinese "transistor tester" units. They don't seem to consistently measure capacitor ESR. I've had readings that vary by as much as 200% in successive measurements even if I thoroughly discharge the caps between each reading.

I opted in the end to purchase an ancient LCR bridge. That is incredibly consistent, plus it does inductor Q which is nice. Cost about the same on ebay as a higher end transistor tester. Uses the same method w2aew uses to calculate the ESR as well wrapped in a bridge.

Shock:
Probably worth a punt for a $10 or so Chinese meter with free shipping though, mine seem to take reproducible measurements but I've hardly put them though a workout.

I agree sinking some cash into a decent LCR meter is worthwhile in the long run. Multiple frequency support and a wide capacitance range is important as well, as you can be comparing apples and oranges if you're not testing to the frequency on the datasheet. So the DER EE DE-5000 is another option.

Some decent caps can self heal or reform unless they are too far gone, like leaking electrolyte or bulging. After a time sitting idle, depending on when you are testing them in their life cycle this can throw out results.

I've seen SMPS caps or ones placed next to warm heatsinks (especially the cheap brands) their life expectancy seems to be under 3 years for partial or total failure. Heavy hours or really poor design I'd give them a year tops.
MrSlack:
I've got 55 years out of some Sprague ones so YMMV :)
bitseeker:
@richfiles: Any news on your Mastech?
richfiles:
No new news... Hours have picked up at work, and I've just not sat down with it. What free time i have, has been applied to other projects, like my Kerbal Space Program controller.

Don't worry! I haven't forgotten about this thing.
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