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sgerus 30th August 2011 01:23 PM

MC250 Input Section Voltage Question
I just purchased a MC250. This is my first McIntosh amp.

When checking the voltage on the input section printed circuit board I noticed that the voltages at C55 and C56 where at +/-20V instead of +/-15V per the schematic.
I changed R111 and R112 from 3.3K to 5.6K to get the correct voltages

It looks like the input section uses 4.4mA. R111 and R112 now drop about 24.6V (5.6K * 4.4mA= 24.67V)

The schematic I have is for PCB 043-795 My amp uses PCB 044-557

Does anyone have a schematic for PCB 044-557?
Does this fix make sense?

Thank You

taydonet 27th January 2015 02:51 PM

nobody answered ? I would like to know also, I have same voltage reading

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