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In Reply to: RE: McIntosh MA6100 repairs posted by Michael Samra on April 15, 2017 at 18:17:54
I used MJ15003G, the same shipped by McIntosh.
There is one further thing I've noticed. After playing music for a couple of hours, one channel's heatsink is still warmer than the other. All DC measurements I can take between the two channels have them very close to one another. The only difference I can find is that on Q405 on the warmer channel, I measure about 22Megohms between base and emitter. On Q406 on the other channel, no resistance registers on a Fluke DMM.
At idle, there is no difference.
Unfortunately, no generic transistor cross seems to be known for Q405/406 (132-081), meaning I'd have to order from McIntosh, which takes about 3x as long as ordering from Mouser.
Some of that is due to the different numbered components between the channels.BTW,the MJ15003 and MJ15004 you can buy at Mouser or Newark.I bought 100 of them two years ago and I have 32 of them left. 22meg isn't really a problem.Do you have a way to run a power output test and distortion level?
"For every complex problem there is an answer that is clear, simple, and wrong" H. L. Mencken
Yes, I bought the MJ15003G from Mouser, but I also bought two from McIntosh because the owner wanted them sourced from McIntosh -- the first time, before the second channel blew on the bench. All are by ON Semiconductor.
I've done full-power bench tests into a resistive dummy load and a crossover distortion check at low power. All that is fine. Both channels are putting out above rated power, checked individually. Clipping is symmetrical.
I don't have a distortion analyzer. Yet.
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