Good idea, Doug.

I had another (different) thought about the sticking buttons today.

If it is due to dirty switches and debounce problems, then there would be a very simple way to force a reproduction of it. On one of the in-house test units, solder a couple of variable resistors in place of the volume switches. Turn them up and down slowly and see if they cause the runanway condition. If so, then you need to look at switch glitching as a possible cause. If not, you could probably rule it out.

Tony Fabris
Empeg #144