Tuesday, May 29, 2012

How (Not) To Fix A Stereo Amplifier

     I've been using my parent's old stereo amplifier at school to play some tunes in the living room. It lasted almost two semesters but near the end of last semester, one of the channels was cutting out and eventually they both died. I know that large electriclytic capacitors are prone to going bad so I checked those first. Sure enough, they were swollen. I got my hands on a suitable replacement and hacked a way to switch the new ones in for the old, but unfortunately the replacements didn't fix the problem. Since this didn't bring it back to life, and with the stereo being so old, I'm going to put it into the junk pile for scavanging parts from it later on. I had hoped switching the capacitors would do the trick so I took pictures along the way to write a blog post about. Even though it didn't work, here's some photos of what I did.

Pioneer SA-940

Original Capacitors -- You can easily see that they are both swollen

Footprint of the original 56V 8200uF capacitor.
The lead closest to me is negative, the one opposite is
positive, and the third lead is strictly for stabilization
(This is a fairly large capacitor after all!).

Footprint of the replacement 63V 10000uF capacitor.
It's different, but I can make it work.

Where the original capacitors were located.
The top lead is the stabilization lead.

The left spot is drilled for the footprint of the new capacitor.

The final modifications. A capacitor is seated in the righthand spot.

The capacitors soldered in. 

Final resting place.

Another view of the new capacitors.

     Unfortunately this work didn't pay off. At least I had some fun doing it!