Chances are against the buyer on this one. The reason this guy is selling it is because he doesnt want to deal with it, or it costs too much to repair. Either way it is a bad deal. Pass it up unless you know 7000% sure that you can fix it yourself, then give him a lowball price for it. It aint worth taking the risk.
I had an old Carver amp and since Carver sold out and/or went out of business I couldnt find an authorized dealer that I could trust. So I did some research and found that Bob Carver sold rights to someone else to be able to refurbish and sell parts. Unfortunately it was in Washington, so I packaged that old heavy tank and shipped it in for refurbishing. It had the same problem as this PPI PCX-1250 (left channel went out). So anyways to make a long story longer, after I recieved it, I was glad I did the extra research. It paid off. The amp worked like new. I guess what I am trying to say is that sometimes it just seems that you cannot trust your local TV doctor working out of a garage to repair you high end audio equipment. Hope you find a legit place.
If you buy a known blown amp you have to be willing to put at least $100 worth of parts. In an amplifier especially a class D sub amp you cannot just replace one set of fets, it doesn't work that way. Usually if one output fet goes it takes more with it even though it isn't smoked doesn't meant it is good. Dependant on how long this went or the quality of the original components the chances are you could have problems elswhere too. I have seen output fets blow and take half the powersupply fets with it, not a pretty sight. Also another thing to remember is if even if you find some good fets left on the board you need to change all of them anyways to keep the batch/lot numbers all mathing this will help ensure a "Matched Set" which will help with dependability later, it can be quite costly. It can be worth it if you learn how to do it yourself but not if your looking for an amp to use RIGHT NOW, so in my honest opinion, pass it up for a good one...Polo.