The schematic shows that the signal goes from IC4 to the tone stack.
IF you can get IC4 to stop the noise, it would be informing to know if any IC's further down the line are involved. (maybe you did this already)
If the problem is isolated to IC4, I would try the grounded cap test on it's input pin (6).
Seeing that the IC was replaced we must move on.
IF you can get IC4 to stop the noise, it would be informing to know if any IC's further down the line are involved. (maybe you did this already)
If the problem is isolated to IC4, I would try the grounded cap test on it's input pin (6).
Seeing that the IC was replaced we must move on.
Comment