xtant 4180c bad channel

[rjam5]

i have a xtant 4180c with a bad channel. i am trying to figure out how to fix it. the first 3 channels have sound and the fourth has a scratching noise. any ideas on how to fix or where to start. i am just learning and do this as a hobby.

[Perry Babin]

This isn't a good amp to learn with. It's complex and there is no service literature available. It's also an amp that I've never worked on so I have no information on it.

Have you tried operating all controls through their entire range to see if that made a difference?

If it has jumpers, pull them off and put them back on several times. Sometimes light corrosion can make a connection intermittent and can stop a channel from producing audio.