Kenwood KA-3500 Right Channel Static Noise

[decin06]

Hello, I have a 1977 Kenwood KA-3500 amplifier that has static (also crackles and occasionally pops) coming from the right speaker on both channels (A and B). I thought it was a connection problem with the speaker terminals and speaker wires, but the static on the right side continues with headphones on.

The static noise does not get louder with volume, and is the same across all inputs. Also, I cleaned all the buttons, switches, and pots.

Any ideas on what may be causing the static noise? Thanks.

 

[HPMguy]

Probably transistors in the main amp, either the differential pair or the four transistor equivalent, I'm not sure which is in the 3500. Very likely to be some of the known trouble causing ones all the main manufacturers used in the mid 70s, they fail with age. Hiss, pops, static, etc.

 

[decin06]

Probably transistors in the main amp, either the differential pair or the four transistor equivalent, I'm not sure which is in the 3500. Very likely to be some of the known trouble causing ones all the main manufacturers used in the mid 70s, they fail with age. Hiss, pops, static, etc.

Thank you! I will see what I can do.

 

[HPMguy]

Q1-4 on the main amp board, they are the differential pairs. I believe 2SA640 can be replaced by 2SA992.

 

[decin06]

Q1-4 on the main amp board, they are the differential pairs. I believe 2SA640 can be replaced by 2SA992.

Thank you for helping me out, I really appreciate it.