I got this amp. It blows fuses … so need to be serviced !
Music Man 2100-65 schematic (unfortunately not very well readable, specially for the model with 12AX7 that I have ! )
Thermal breaker : I was wondering what the hell was this kind of small “bulb” in series with main fuse … and I found what was a thermal breaker (thanks to google !)
Short circuit 6CA7 plate to ground capacitor
Hence, the output transformer is not in very good health
RB1 rectifier board
Unsoldering the dead plate capacitor is not sufficient. Fuse still blowing. Before testing the power transformer, I’d like to understand the rectifier and filter boards layout …
Power transformer check (secondary VAC, without tubes, PT wires desoldered)
Bad 100uF filter capacitors
OK guys ! electrochimic capacitors changed, output transformer changed, the beast is all right and sounds loud ! It’s a 3-65 OT from Mojotone
How to bias this thing : see there (pacair forum)
Earth and ground
I got a nice Musicman 212 HD 130 (2475) to service. Bad power transformer and red glowing plate EL34. Works fine now !
Links on the web :