Don't try to run before you're walking...
Is the buzzing still there when you disconnect the amp from all audio inputs and have it running with only the speakers attached?
If not, are you certain that you are not connecting it into a noisy source?
Have you tried connecting a different amp to the same source to test this?
Is the source drive level compatible with your input? If not you may simply be overloading the input stage on the amp causing hard clipping in the output stages etc.
Sticking your finger here and there on the board will not achieve anything other than popping a transistor or chip if you're unlucky, so don't do that any more.
A common problem I have found on small-ish surround amps is a leaky bridge rectifier placing mains hum on the DC lines. This could possibly be your problem.
The Bridge Rectifier, in case you don't already know, is the 4 legged device you see mounted on the Aluminium bracket/ heatsink at the top of pic3 and marked + ~ ~ -.
The only other problems I have seen with them are blown outputs due to shorted cables. This is usually accompanied with a burning smell around the area the outputs are located, sometimes a bubble or hole is present on the devices that are blown.
The output device on your amp is a 20 odd pin chip mounted under the bracket at the back of the finned heatsink. I think this is unlikely in your case, but it could still be faulty and presenting DC to your speakers.
rgds
The bridge rectifier has 4 diodes in it. See the diagram on the wiki page. The + and - symbols are the same as marked on yours. You need to check all 4 diodes in the bridge, forwards and backwards.From what it looks like, the bridge rectifier is performing as it should- despite being backward in terms of anode and cathode.
Sounds like the source of the buzzing is the audio source. Try a different source of audio for the amp instead. A battery powered item would be best.longtallsally said:No, the buzzing is not there when disconnected from audio inputs. I have tried other amps and different power sources with the same results.
Resistance measurements are pretty useless for this kind of troubleshooting.So I think we are on the right track b/c if I wiggle the volume control plug, all heck breaks loose. Now I just need to know what to measure the resistance across.
The bridge rectifier has 4 diodes in it. See the diagram on the wiki page. The + and - symbols are the same as marked on yours. You need to check all 4 diodes in the bridge, forwards and backwards.
Sounds like the source of the buzzing is the audio source. Try a different source of audio for the amp instead. A battery powered item would be best.
Crossovers will cause distorion or perhaps no sound at all if faulty, they will not cause hum.
rgds
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