Is there a replacement for the power transistors....(from Smolder)
"The reccomended replacement for the 132-070 is the ON semiconductor (Motorola) MJ15003, never had to match them and have used this part in MC250's to MC2300's with equal success. I have found that if you have to replace one do them all, and always check the sandblock emitter resistors, they act like fuses to protect the power supply if an output shorts."
This was a Quote passed on to me from a master of Mac repair, Terry Dewick.
The thing about Macs (and maybe most other amps) is that one thing leads to the next ie changing the resistors if you change the transistors, and if you change that resistor be sure to change that other one, and make sure you put the positve to ground and not the negative on the cans and blah blah and so on and so on... It may be best to get a trained audio tech to handle the repair if one is not familiar with amp repair. Hope this helps answer your question though.....