Boss SD-1 Tone Pot Squealing Problem

[soupbone]

I'm having some problems with one of my Boss SD-1's.It just started doing this;When you turn the tone pot from around noon on,It starts getting a very high pitched squeal.Even with the volume and drive turned all the way "off".I thought the pot was bad,so i switched it out with another pot i had from another SD-1 i had laying around.Same problem. :icon_cry:I've checked and re-checked everything on the board about 20 times,and i am totally stumped. ???Anyone have any ideas?Thanks,-soup

[soupbone]

I take one comment back If you barely turn the volume up,even with the drive all the way down,That's when you can hear the tone knob squeal.

[soupbone]

Figured out what was wrong The "Drive" pot was all the way against the chassis grounding the signal. If Fred Sanford was was alive toady he'd say; "Soupbone,Ya big dummy!" lol