Author Topic: Testing Electrolytics  (Read 805 times)

danrclem

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Testing Electrolytics
« on: March 28, 2016, 01:47:55 PM »
I have a Sherwood amp I'm going to start on and I want to check the crossover caps with a multi meter with capacitance capabilities.  I know conventional wisdom says change them but from what I've read these caps almost never go bad.

My question is, do I just lift one leg and check?  If I lift just one does it have to be the positive or negative leg or does it matter?

I'm going to change the can caps also.  How do you guys do that?  I saw a video where the guy drilled holes in the bottom and ran the legs through.  Is that the best way or should I solder them inside the can to the terminals that run through the bottom.

Thanks

AlexanderMartin

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Re: Testing Electrolytics
« Reply #1 on: March 28, 2016, 07:06:42 PM »
I don't care what people on the internet say or what's "conventional wisdom." IF it's a 50 year old electrolytic capacitor, it goes away. Pull the multi section out, cut it open, pull the guts out and drill holes in the base, and stick your capacitors on the now empty base. Works like a charm.

Ken Doyle

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Re: Testing Electrolytics
« Reply #2 on: March 29, 2016, 02:36:17 PM »
No need to deinstall the entire can, I leave the wiring in place, cut near the bottom of the can with a hacksaw blade while it's still in place, drill the holes in the base, install the new caps wiring them to the terminals on the underside, and stick the emptied can back on with aluminium tape.  I find this much easier, faster, and neater.

danrclem

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Re: Testing Electrolytics
« Reply #3 on: March 29, 2016, 06:19:35 PM »
Thanks guys.  One other question.  On a can with a positive common the positive side should be connected to the can and the can should be insulated from the chassis.  Correct?

eman

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Re: Testing Electrolytics
« Reply #4 on: June 18, 2016, 11:28:55 AM »
An ESR meter is a better predictor of cap usability. I change older filter caps but I mostly leave cans in place and put the replacements on the underside. Im lazy and I dont resell much. Modern caps almost always perform better though even if the old one is measuring right.

Eman