MXR 118 Analog Delay troubleshooting

[MarkB]

Hey all... it's been a while since I poked my nose around here (too long, really).

So I was fixing up some stuff.. found some old circuits I built and never boxed up, etc.. and was pulling out my various stompboxes to play with.  Lo and behold, my MXR 118 (the 'green' one) has decided to misbehave.  It was working the last time I used it (a few months back), but no longer.

So here's the skinny:
It's an original with the 5101 chip (not the PT-retrofit).   It looks to have never been modded.

When I kick it on now, there's just this awful hum/buzzing kind of noise.  I can hear that the delay is still working - if I kick the regen way up and feed it some signal, then play with the delay time - I can hear it pitching up and down as I tweak it.  I've checked for bad grounds, etc - pots, jacks, etc.
I don't SEE any burned components, leaky caps (not visually, at least).

Any bright ideas?  I'd hate for this guy to go belly up.

thanks!

[MarkB]

Nobody?   

[PRR]

Bad ground.

They can be hard to find.

[MarkB]

That was my thinking too, initially.. if so, they ARE hard to find.  These old pedals are a mess.