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Sansui 5000A

Komet's picture

Hello anyone who is experienced with Sansui's 5000A receiver I would a appreciate your help with a few problems.
When turned on and going from off to speaker A there is a large popping sound from the speakers. This even occurs after letting the receiver warm up for 5 plus minutes.
The other issue is there is also a low frequency buzzing noise coming from both channels that doesn't increase with increases in volume and tends to decrease in it's intensity one the unit warms up. But it is always there in the background none the less!
Now I have checked the PS voltage across the filter caps and it is 76.5 Vdc in the left channel and 76 Vdc in the right, which are both within the factory spec of 77Vdc. I also set the bias of both channels with 8 ohm/200w dummy loads to Sansui spec of 23uA and checked DC leakage which was almost nil.
So any guidance for troubleshooting these problems would be appreciated

karodimitrov's picture

Re: Sansui 5000A

Check and possibly replace the electrolytic capacitors in the power supply(C 003,C004)and output caps(C005,C006).In principle all electrolytic capacitors.They are for 40 years.I think the buzzing comes from bad filtered power supply.For a start you can connect in parallel of C003 and 004 two caps 2200/80 and hear is there a difference.(no buzzing).If it's OK-replace C003,C004 with some new-I think 2x 10000 will be better.Оnly assumptions for the problem.