Not exactly sure without seeing the unit. If you want to send it to me I’d be happy to look at it for you. Or... my studio maintenance teacher always told me “eliminate the fear and open the gear.”
What is the master volume knob doing? If you are getting static, I would remove the know and hit it with some contact cleaner. A lot of times they just have dirt in them.
You may just be able to pull the knob off without opening it up. Spray some contact cleaner In the pan pot. This is a common issue with all music gear.
