dpinx

Hello, I am working on repairing a SW-10 that seemed to have a few of the typical issues that are listed in this thread. Blowing fuses, DIAC needing replaced, Q5 upgrade, recapped with nichicon, new MOSFETs.. etc. I managed to get to the point where I believed everything was good to go. ~6V across the resistors and no more fuses blowing. However, no sound other than faint muddy noises if anything. I noticed that the area around TH1 (under one of the screws for the 5 MOSFETS) had looked liked it was burned out around it. TH1 reads 79.5ohm though, so I didnt believe it was shorted. A little later into my investigation of the backplane I happened to notice that the outermost cap (10uF 50v) from the gain pot was twisted enough to short the leads... Naturally, i carefully un-twisted them before proceeding. I can see traces & pins of the cable connecting the two PCBs lead back to TH1, so I am assuming that TH1 was taken out with the shorted cap. All I can get the sub to do is thump along now, but it is "muddy" and an obscure few hits at best. Does anyone know what TH1 is value wise? is that the only thing that could be causing the issue? My guess is that I may need to hook this up to a scope next.