Jon,
Thanks for your advice on the Hafler XL280 I have. I have done some work but still have problems. Here's the list. I replaced R17 1k, R19 330, Q12 2n3440, Q11 2n5415, Q10 2n5401, and nearby Q7 and 8 both 2n5401. I assumed the MOSFETs were okay and left them in. A moment of weakness for sure. And for lack of a Variac I used a 40 watt bulb in series. At power up the right side comes up normal just as before and shows 20 to 20 mv at the speaker out terminals. Bias test across the fuse as indicated in the manual shows 300 mills as it should. On the bad left side though the output at the speaker terminals shows about 300 to 400 mv out and drifts around. No longer the 40 volts. I can see no bias current at all across the fuse. Any thoughts? This is getting beyond my tech skills. I have no problem working on the boards, I just am not good at diagnosing. I could take this to a local shop, but enjoy doing the fix myself, if I can. Thanks. Bill