Peavey VTM weird oscillation (FYI & fix)

[RIFF]

So I fired up my VTM 60 yesterday, and as I started to play, its making a weird low frequency oscillation that is overwhelming the output.
So.. I turned it off and started trying to track it down.. (cables, tubes, dip switches, settings, etc.)
All else exhausted, It ended up being the largely unused effects loop jacks. I cleaned them out and plugged some cables in and out, and no more issue.
Had my freaked and ready to find a tech for a bit.

 

[BeZo]

What did you use to douche them out?

 

[anomaly]

That's a common problem with lots of older amps. Either put a patch cable in the loop or clean the contacts.