mr_fender
Axe-Master
Here's something interesting. When those clicks and pops aren't present (the unit currently isn't doing that), the INSTR IN adjustment works. I need to double check this and confirm that it doesn't work when the clicks and pops are actually happening but if I remember correctly that's the way it was.
What do you mean by the Instrument In adjustment works? Are you unable to change the setting at times? That control is compensated, so you will not hear a change in volume unless it is set very high or very low.
Also, does it make the noise going through the Headphone out?