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Old 28th September 2011, 08:27 PM   #1
miligor is offline miligor  Serbia
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Default McIntosh MA7000 overhiting

Sorry, overheating...
The amplifier working normaly, except that one channel is very hot. Bias is 60 times bigger than bias in other channel, and I can't adjusting it. Bias adjust trimmer is on the minimum, but bias current is too high. I don't have service manual or schematic. Power transistors are Onsemi "Thermal Track" NJL3281D/NJL1302D - 12 pieces per channel. Do anyone have an idea what could be the problem here?

Last edited by miligor; 28th September 2011 at 08:30 PM.
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Old 10th October 2011, 12:56 PM   #2
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Maybe Terry DeWick can help you. He's a nice guy. You can mail him at:

Een volk dat voor tirannen zwicht, zal meer dan lijf en
goed verliezen dan dooft het licht…(H.M. van Randwijk)
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Old 11th October 2011, 12:13 AM   #3
djk is offline djk
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McIntosh will provide a manual if you give them the sereial number.

I would check for a shorted driver or predriver.
Candidates for the Darwin Award should not read this author.
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Old 27th December 2014, 10:17 AM   #4
RJEL is offline RJEL  Norway
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Location: Bodo
Three year old thread but I try......
I have the same problem.
If you have fix it maybe you could tell me what was wrong?
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