Hi everyone,
I am new to this forum and would greatly appreciate if anyone could assist me with this problem.
A friend of mine gave me an old Sansui AU101 amplifier to help him fix it. When I power on the amplifier and turn on the volume, even without an signal plugged in, it gives out a crackling sound from both channels and gets louder and louder. If I bypass the preamp and connect directly to the left and right power amp circuit, it works perfect. I have replaced all the small signal transistors(2SC871) and capacitors on the preamp board but the problem still exists. Pls advice, anyone. Thanks.
I am new to this forum and would greatly appreciate if anyone could assist me with this problem.
A friend of mine gave me an old Sansui AU101 amplifier to help him fix it. When I power on the amplifier and turn on the volume, even without an signal plugged in, it gives out a crackling sound from both channels and gets louder and louder. If I bypass the preamp and connect directly to the left and right power amp circuit, it works perfect. I have replaced all the small signal transistors(2SC871) and capacitors on the preamp board but the problem still exists. Pls advice, anyone. Thanks.
that is an old amp, make sure all contacts like volume controls are clean...if you can replace them, that will be a good idea...
Service manual available free here,
HiFi Engine | Download Free User/ Service Manuals, Amplifier, Receiver, CD, Tape, Tuner, Video
If the noise reduces as you turn the volume down and is on BOTH channels might e worth looking at the PSU for the preamp.
A quick scope check should find a fault like that in minutes 🙂
HiFi Engine | Download Free User/ Service Manuals, Amplifier, Receiver, CD, Tape, Tuner, Video
If the noise reduces as you turn the volume down and is on BOTH channels might e worth looking at the PSU for the preamp.
A quick scope check should find a fault like that in minutes 🙂
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