I've got an MXR Carbon Copy delay pedal that's been sitting around for a few months, and when I went to use it today, I noticed a really high pitched noise coming from it. The noise seemed to change in pitch as I messed with the delay speed knob, and it seemed to almost disappear when I turned the delay speed all the way up. It's not the loudest noise, but it's loud enough to be an annoyance. Is there an easy way to fix this, or would I need to order a replacement part or do some soldering? I haven't worked much on pedals, so I'm not sure how much I'd want to screw around with the circuitry.
I tried using it by itself with just a 9v battery, single cable from guitar-pedal-amp, and it's still having the same issue.