Mesa Boogie reverb madness

[soberskipper]

I'm new to the forum and would like to start by Hi to everyone


I am cleaning up a Boogie Studio .22 (1st version) for a friend and have noticed when the Master is all the way up, the Reverb makes a horrible noise if I touch the spring holders, wires leading from the tank, or the inputs with my chopstick. Also makes the noise as the Master pot is turned. When I remove the reverb tube, it sounds fine with the Master dimed. I have tried all the preamp tubes in my supply thinking it might be a shady tube but they all do it. Also, have replaced the 6BQ5 set just to see.

When I back off the Master a bit, the reverb is useable and sounds great.

There is a single, very small diameter (maybe 26 gauge? it's super tiny) leading from the middle spring to *nothing*... I can't tell if it once was connected to something but I can't find it on the schematic. I'm thinking it might connect to one of the other springs?

I read the manual and understand the part about how they say that the circuit is basically unstable in certain conditions... is this just how the reverb behaves with Master on 10?

Does anyone know if this loose wire could be the cause of my problem?

thanks,

uri g.

[Twist]

Could you post a picture of the mystery wire?