Frontman 212r (yes another one)

[lowell]

So this thing came in distorted, even on clean channel. Opened 'er up and found a missing + or - low V rail. Forget which one, as it's back now after I fixed it before. One of the 5w lowV dropping resistors originally had a broken lead. I replaced it and returned it to the customer. In any cases the voltages are good and my previous repair is fine. Now the thing came in distorted again... but voltages all check out good. This time the distortion was even there going into the PA in jack. So I then began to troubleshoot some more and now the thing is working fine. I cannot get it to act up again. I fear the problem is still there, but not sure how to make it act up again. I've whacked my fist on it, poked around on largish components, power cycled it, fiddled with knobs/jacks etc... sounds fine. Any thoughts?

[lowell]

I also just ran it at 60watts into a dummy load for 20 minutes. Still no problem. I've laid the thing down on its front, on its back etc... rocked it back and forth to reveal any loose connections. Seems like something electronically is failing intermittently. But if the dang thing ain't acting up I can't fix it.

Anyone have any suggestions on getting an amp to act up? This is one of those frustrating repairs, I know it'll act up again when the guy comes to get it. Ugh.

[Gtr_tech]

Loop jacks clean?

[lowell]

yes forgot to include that... I fiddled with them, plugged into them a bunch of times to see if anything arose... nothing.