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Hi, as a radio technician from the 60's I am trying to fix the amp. The issue i have is that the two valves are 6L6GCR made in China, and I am having a problem with the bias setting - 8A-10C board. The chassis is 2100-B-AX. Would appreciate comments. Thanks, Peter.
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There is a really good Music Man chat board that I subscribe to. You may find what you need therein. Lot of tech resources. Happy hunting.Originally posted by Peter March View Post
Topics - Music Man Amps Discussion Forum -
What's the problem?
I've worked on a lot of MM stuff, but don't recall this particular one, is this the tube driver or is it the solid state cathode driven version?Comment
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It is the solid state cathode driven one, on the 2100-B circuit board. With just the one adjustment compared to two in the Fender models - bias and balance between the two in that brand - there is only the one adjustment here. Therefore with only one measurement across the 3.9 ohm resistors for what I understand is 25 mV to be set, what happens if the other 3.9 ohm resistor has a higher or lower voltage across - what is the preferred maximum and minimum voltages between them that the set up has to keep them?
Cheers,
PeterComment
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If I remember correctly 25mv is the maximum so you adjust so that the higher of the two does not exceed 25mv. There was some discussion of how to get these things to be more even but I think that would involve swapping transistors.Originally posted by Peter March View PostComment
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