Hello, I'm new to this site but have been in the field for years. This is my first posted thread.
I've been doing some repair work on numerous amps, receivers lately. Replacing main filter caps on two different amps I've come across a problem. Running through and replacing 20 year old caps in two amps I have had the same problem two times and can't seem to figure out what's up. On the latest, I've replaced two 6800uf 100v caps on a Fisher CA-800. When powering up the amp the power meters pegged out. I looked the amp over and hadn't done anything wrong. No reversed caps and no debris left on the board. I use compressed air to clean up everything prior to turning anything on. The amps original caps were 6800uf at 68wv. Obviously the replacements will work. I tested the caps prior to installing and all seemed fine. They actually tested great. Near 6800 and .01 esr. I had replaced all the caps at one time and didn't know if I stupidly got one reversed but I checked and all was fine. After a couple hours scratching my head I decided to reinstall the original filters. Powered it up and it was fine. I checked the new caps again and they seemed ok so, I reinstalled them again and whammo! Meters pegged out again. If replacing 68v with 100v isn't the problem, what could it be? Any help would be favorable.
I've been doing some repair work on numerous amps, receivers lately. Replacing main filter caps on two different amps I've come across a problem. Running through and replacing 20 year old caps in two amps I have had the same problem two times and can't seem to figure out what's up. On the latest, I've replaced two 6800uf 100v caps on a Fisher CA-800. When powering up the amp the power meters pegged out. I looked the amp over and hadn't done anything wrong. No reversed caps and no debris left on the board. I use compressed air to clean up everything prior to turning anything on. The amps original caps were 6800uf at 68wv. Obviously the replacements will work. I tested the caps prior to installing and all seemed fine. They actually tested great. Near 6800 and .01 esr. I had replaced all the caps at one time and didn't know if I stupidly got one reversed but I checked and all was fine. After a couple hours scratching my head I decided to reinstall the original filters. Powered it up and it was fine. I checked the new caps again and they seemed ok so, I reinstalled them again and whammo! Meters pegged out again. If replacing 68v with 100v isn't the problem, what could it be? Any help would be favorable.
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