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Author Topic: Testing Capacitors  (Read 2282 times)

Ryan Schoolcraft

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Testing Capacitors
« on: November 18, 2014, 02:00:26 pm »

I have an audio amp and im trying to diagonose the problem. The Capacitors are rated for 100V at 2200 microF and when i test them all I get is 64microF. I tested them resistance and they seem fine though. Can anyone shed some light on this for me?

It is a QSC Audio USA 1300 and only one channel is working

John Roberts {JR}

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Re: Testing Capacitors
« Reply #1 on: November 18, 2014, 02:02:43 pm »

Fix your name...

Then test then disconnected from the circuit.

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Craig Leerman

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« Reply #2 on: November 18, 2014, 02:44:15 pm »


Please go to your profile and change the "Name" field to your real first and last name as required by the posting rules displayed in the header at the top of the section, and in the Site Rules and Suggestions in the Forum Announcements section, and on the registration page when you registered.

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Riley Casey

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Re: Testing Capacitors
« Reply #3 on: December 12, 2014, 04:43:46 pm »

Tear and compare.  If one channel is working correctly start measuring how the DC voltages are different between the channels.  If they are different ( and I would surmise if you're test 2200 uf 100V caps that your looking at the main filter caps ) which supplies are different, high voltage, low voltage?  The input circuitry doesn't run at 80 volts or what ever the outputs devices run at.  If the outputs are DC coupled as I remember some of the low end QSC were then a failed cap would not pass signal but all would likely be good up to that point.  Do you have a scope, is it showing good signal on both channels up to the output caps?  Large electrolytics do go bad with age and heat so not a bad thing to be suspicious of and relatively cheap to swap out.

Steve M Smith

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Re: Testing Capacitors
« Reply #4 on: December 13, 2014, 04:12:04 am »

only one channel is working

If this was mine, I would swap the capacitors over between channels and see if the problem moved with the capacitor or stayed with the same channel.


Mike Diack

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Re: Testing Capacitors
« Reply #5 on: December 15, 2014, 06:30:46 pm »

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