UGH! What a great amp... I have run this thing HARD for the last five or 6 years and it finally crapped out. It's literally one of the first ones off the line... I immediately had problems with it (some weird effects loop thing) and sent it back to the factory... they did a bunch of updates under warranty and sent it back to me, and it has been my number one workhorse since then. Right when we were getting ready to soundcheck yesterday, I fired it up and played through it for about a minute or two... and then it was as if someone slowly turned the volume down into nothing. I let it sit for about 10 minutes while I helped with some lights... it worked great and then did the same thing. After that, I bypassed my pedalboard and power conditioner... plugged into the wall instead of our distro... tried different cables and switched speaker jacks... same thing. Took it home last night and tried a different cab... then I swapped out all of the tubes for a different set... same thing. Anyone know what this might be? I'm dying inside right now... I absolutely LOVE that head and I have babied it. It has been my number one tone monster for so long and so many gigs, I feel like I want to cry. Mesa is closed today... ... so any insight from the board experts would be great!