Acoustic Research/Sunfire Subwoofer amp clipping

[DigitalDisaster]

I have a 5-year-old ARS500 subwoofer. The amplifier is a Carver Sunfire 500WRMS unit that is clipping badly at moderate to higher levels. I have replaced the 15" driver, and it was not the problem.
Nobody wants ot touch this thing as Acoustic Research is no more. I love it too much to toss, as it blew away Velodynes costing 4 times as much when it was operating properly. The amp has huge wound capacitors.
I'm not an expert - where should I start, or is there anybody on this board that would feel comfortable tackling it this job?
Thank you,
Bob
Glendale, AZ

[DigitalDisaster]

Should I just replace the output transistors?

[Ivan]

Try testing the transistors first. Look for a shorted one or one that reads different than others (same type). I am assuming that there are pairs of transistors in the output stage. Any DC voltage on the output with no input signal?