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RE: McIntosh MA6100 repairs

Posted by Thermionic27609 (A) on April 13, 2017 at 20:17:32

In Reply to: RE: McIntosh MA6100 repairs posted by Michael Samra on April 12, 2017 at 17:39:20:

OK, on more testing, there may still be a problem.

In one channel, when on, the voltage drop across the emitter resistors at idle is about 2mV, and it remains stable.

On the other channel, the one I just fixed, the emitter resistor voltage drop starts at around 3mV, but slowly creeps up as it stays on, just sitting there, up to 17mV when I turned it off.

I have not replaced the differential pairs in either channel or the next transistor Q405. All other transistors on the driver board have been replaced, plus the output pairs.

I think you have to order Q405/Q406 from McIntosh. Then there is the temperature compensating diode on the heatsink.

Where would you suggest I direct my attention next?

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