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Is this tantalum capacitor damaged?

by gnurf
Tags: capacitor, damaged, tantalum
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Feb2-13, 03:09 PM
P: 330
I'm troubleshooting an old (1995) LeCroy scope that has shown some irregular behavior lately ("multiple calibration errors" warnings, display freezes for a while when changing the volt/div and time/div settings, etc), especially after running for a while. I won't bother you with all that—I'm just wondering if the cap in the picture is damaged? The picture quality is not great, but it's the best I could do. I thought it looked worse in a 4X microscope where the bump seemed darker/grey/black in the middle. Any thoughts?
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Feb4-13, 10:21 PM
HW Helper
P: 5,486
I have no idea, though I can see why you might wonder. Are there others on the board that you can compare with? If you can see a manufacturer's name, maybe try their web site there may be photos of their products there.

Good luck! Very disheartening to have to bin a piece of equipment for being unable to trace a faulty component worth a few cents.
Feb5-13, 04:07 AM
Sci Advisor
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davenn's Avatar
P: 2,735
how does it comapre to the one in the upper right of the pic
the one partly hidden by your enlargement inset ?


Feb5-13, 04:37 AM
P: 330
Is this tantalum capacitor damaged?

Vishay has tantalum series (e.g. 595D) that look exactly like that:

I'm still not sure if it's a sign of damage or not, but the other similar looking caps on the board do not have this bump, and Vishay, of course, wouldn't put one of their ugliest ducks in a marketing photo. Anyway, I've replaced it now and after a complete disassemble/reassemble it seemingly works again. Time will tell, I guess.

What is certain is that the scope (which I got for free) is not going in the bin any time soon. It's a 500MHz-2Gs/s monster compared to what I had before, and the fact that you can download the complete 400 page manual complete with schematics, BOM list, etc, blows my mind a little bit—very educational! You old heads had it too easy. :)

Edit: Btw, I measured the capacitance once the cap was out of circuit and it was within spec. Google: Is there some definitive capacitor test I could do?

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