Morning all - It's been awhile since I posted but I'm to my wits end and just wanted to reach out and see if there was an input I could get based on my situation. I'll give you the readers digest. Ampeg SVT 6 Ampeg PR410hlf Hooking up for sound check at show - Turn on my amp, turn up my volume, play 3 notes waiting for my turn to check - goes silent. I all of a sudden have no output. No pops, no crackles no nothing - just goes silent. DI the amp and nothing. Drop the head off at my local shop (In St. Louis) and they go over the SVT 6 and find broken soders and some ground screws that came loose (one fell out). All was put back into place and benched checked and everything checked out fine. Got to practice and plugged it all in - no output. The head does work now. The problem seems to also be with the cab and I'm baffeled how I could have a problem with the HEAD AND CAB at the same time. I'm getting only sound out of the horn of the cab, and it's crackly and extremely quiet. I get nothing out of the drivers. I opened the back panel and nothing is burnt and both fuses are intact. I'm absolutley stumped on what it could be - and what culd have caused it. I do not have a power conditioner - I need one. The Ground screws that were shook loose internally - curious on if that could have caused any sort of surge to the cab and fried the internal board Checked all cables with other amps - all work fine. Head works fine with another cab and with DI AH FUHQ I didn't check the Speakon cable - but I did run a seperate head to the cab (not with that cable) and it was the same result. I'm a bit broke now since I had the head looked over and worked on - any ideas?