AMI Rowe CD100F Volume constantly fluctuating

I'm trying to help a friend who just bought a ami rowe CD100F venus jukebox. It needs a little fixing up here and there (bulbs, animation motor, etc). Right now we're trying to figure out why the volume is fluctuating. It doesn't crackle, or make weird noises, it's just like a kid is playing with the volume knob intermittently. Right now, the volume on the back of the machine is disabled and someone installed an IR kit with remote. I was thinking of hooking the pot back up and disabled the IR kit as a test, but not sure what to do. I don't want to break anything as it's not my machine. Does this sound like it's an the IR volume control center or in the amplifier? I do know the machine has a brand new pro player installed. Thanks for your help!

Rowe had that problem with the IR remote--there is a "fix" for it in the instructions that came with the kit--
If you don't have them, just dis-connect the IR--see the service manual for wiring of the behind the box control. Ron Rich