Your Repair Issues: Symptoms & Diagnosis/Fix

[Lone Star State]

Hey everybody. I own two Lone Stars, a 1x12 & a 2x12. I've had a repair issue with both of them. I thought that we might be able to start a thread to post any repairs we've had done on our amps and a description of the symptoms. Perhaps we can help save our repair techs some diagnosis time and possibly spot any patterns or common issues that Mesa would like to know about. Please avoid any flaming of M-B in the process.

I'll post mine as a response to this intro.

Maybe we could get a sticky for this.

 

[Lone Star State]

Symptom: OK the first amp's problem was that there was no sound from my drive channel but it would come on a little if I pushed in on the Clean channel pot.

Fix: A piece of the insulating foil from the inside of the cabinet had detached a bit and was haning down, and making contact with the pot, shorting it. The tech re-glued the foil & everything is good.

Symptom - Amp 2: No sound when FX loop was turned on. FX send pot was relatively 'dead until it was almost dimed, then there was only a slight increase in volume but nowhere near what it should be. I checked the driver tube - not it. It's currently in the shop. I'll pick it up monday & post the diagnosis & fix.

 

[cnumb44]

Symptom: unacceptable hiss on channel 1 regardless of volume or tone settings. Happened with 50 or 100W and didn't matter what rectifer mode.

Fix: Earlier in its life I had a blown power tube. When that blew it took a screen grid resistor. With the resistors replaced for all the tubes it is as quiet as I expect from a tube amp.