C84 died after 5 years

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C84 died after 5 years

Postby mltamisin » Tue Apr 23, 2013 5:57 pm

One of my C84's just bit the dust. Weird because it worked for years. Any ideas? I'm not getting any sound unless I slam it and its noisy and barely audible. Switch go bad? I reflowed the solder on the switches just in case..... swapped slots if it were a bad power ribbon cable but all is fine there. I've sent my entire build to Tim 4 years ago for a PSU update and it came back in tip top shape and he checked the build so I know the build was done correctly. It's never been moved. I know it's only been about 4 months since I've used it to mic some toms.
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Re: C84 died after 5 years

Postby tpryan » Wed Apr 24, 2013 11:09 am

What version is it?

What are the voltages at pins 1, 4, 7, and 8 of each op-amp?
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Re: C84 died after 5 years

Postby mltamisin » Wed Jul 17, 2013 9:10 am

How do you check voltage on the legs of the opamps?
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Re: C84 died after 5 years

Postby twelvetone » Fri Jul 19, 2013 8:55 am

Put the negative lead of your meter at ground and the positive lead at the pin of the op amp. The DC reading is your voltage at that pin.
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Re: C84 died after 5 years

Postby mltamisin » Tue Oct 29, 2013 11:59 am

Okay. Board is Revision 1.9.1. Finally got around to testing the opamps:
U1:
1=32mV
4=-18V
7=36.5mV
8=18V
U2:
1=389mV
4=-18V
7=.41V
8=18V
U3:
1=11.62V
4=-18V
7=15.3mV
8=18V
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