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Dec 25, 2015

CD3000 slight hum on right channel

I’ve been fixing up my old  (1998) CD3000 - so far replaced power supply caps and power amps, and audio signal coupling capacitors on the main board but i can’t get rid of a slight hum/buzz from the right speaker.

 

It sounds like an earth loop, doesn’t vary with input source or volume and the right speaker also seems slightly quieter and definitely lacking in high frequency response.

 

Buzz is not present when powered with a DC adapter eg from Soundlink but the output is still a little muffled on that channel.

 

Any ideas?

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Re: CD3000 slight hum on right channel

Author Accepted Answer selected by JP99

For the benefit of the search.

 

The problem was in the 1000pF x5R capacitors linking the ground planes on the power amp (c57/c59).

I also changed the same parts at the other end of the interlink cable on the main system board, in case it was a bad batch.

 

I’ve never known ceramic caps go bad before, but with all of them changed along with the new electrolytics, the unit is working fully - the sound is nice and bright and the hum gone.

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Dec 25, 2015

Re: CD3000 slight hum on right channel

Author Accepted Answer selected by JP99

For the benefit of the search.

 

The problem was in the 1000pF x5R capacitors linking the ground planes on the power amp (c57/c59).

I also changed the same parts at the other end of the interlink cable on the main system board, in case it was a bad batch.

 

I’ve never known ceramic caps go bad before, but with all of them changed along with the new electrolytics, the unit is working fully - the sound is nice and bright and the hum gone.

View solution in original post