It was working fine until today. I plugged it in, it was the only pedal in the chain and a high pitched whine came through the speaker every time I turned the pedal on. I tried adjusting the dials, it made no difference.

I tried it with a different speaker, same thing, Then I swapped out the cables, used a different speaker, used a different guitar, and finally, tried different pedals. Everything worked fine except the Soul Food, so I have to conclude that it’s the pedal.

Since I last played it, nothing happened to it. I didn’t drop it, no liquids spilled on it.

What could have caused this? And how can I fix it?