Odd issue with Rectoverb II

[jwgreene86]

Suddenly having some odd issues on my Rectoverb II - the clean/pushed modes (channel 1) started having a slight buzzing to the notes, and when the master's turned up past about 2-3, it's just a nasty squeal. Issue is not present on channel 2. Thoughts?

 

[jbird]

Pre-amp tube!

 

[jwgreene86]

Meh, thinking it's more. Looks like a resistor got taken out, possibly on the clean circuit.

 

[JoeDogInKC]

Does it persist without a guitar plugged in? Sounds like preamp microphonics to me as well.