Hello All,
Before and after a full Electrolytic recap I am still getting a crackling noise much like the sound of a dirty vinyl record. It comes on after about 5 minutes from power up and last for about the same time then disappears. It is independent of the volume control which has no effect on the noise.
I have checked all the solder joints through out the amp board and power supply which seem fine, I have removed all the out put transistors and cleaned the contact and put new thermal pad on. I am now thinking component failure. There are a number of those nice old brown carbon resistors on the amp board
(none of the resistors look burnt - generally this amp is in good condition). My thought is to just replace them. If this were a transistor issue would the amp just fail? I am also assuming that the issue is very likely on the amp board and not power supply. All controls are clean.
Any thoughts and help I can get as to where I should go from here is most welcome. Images attached for reference.
Also the Offset is 0V DC both channels and Bias is 25mv per channel as per the service manual. All measurements stable.
Cheers,
Clive I think this should be in the DIY section, but not sure how to move it.
Before and after a full Electrolytic recap I am still getting a crackling noise much like the sound of a dirty vinyl record. It comes on after about 5 minutes from power up and last for about the same time then disappears. It is independent of the volume control which has no effect on the noise.
I have checked all the solder joints through out the amp board and power supply which seem fine, I have removed all the out put transistors and cleaned the contact and put new thermal pad on. I am now thinking component failure. There are a number of those nice old brown carbon resistors on the amp board
(none of the resistors look burnt - generally this amp is in good condition). My thought is to just replace them. If this were a transistor issue would the amp just fail? I am also assuming that the issue is very likely on the amp board and not power supply. All controls are clean.
Any thoughts and help I can get as to where I should go from here is most welcome. Images attached for reference.
Also the Offset is 0V DC both channels and Bias is 25mv per channel as per the service manual. All measurements stable.
Cheers,
Clive I think this should be in the DIY section, but not sure how to move it.
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