industrialarts
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- Mar 25, 2019
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Hi
I have a Boogie MK III Red Stripe on my bench with low gain in the Rhthym mode. When I engage the Rhthym 2 the tone thins out and the gain drops some more.
I have fixed hundreds of guitar amps but am not so familiar with Boogies, I have fixed less of them than any other amp. However, I have been digging for a while and am stumped. The LDRs and relays are all working best as I can tell. When in Lead mode the amp can be driven to full power but the Lead Drive acts funny. When I bring up the gain it jumps to full then starts to attenuate a bit. The pot is working fine - I can read the resistance of the wiper and if I disconnect the wiper from the lead gain stage the signal acts properly.
The tube amp stage all have gain. The weird thing about the Boogie for me is the Rhythm channel coupling to V2, where there is a big gain drop and filtering.
I suspect both problems are caused by the same culprit but all my readings don't point me in any direction. I have yet to remove the pc board since it's such a PITA and I was thinking a failed component would show up by now. I don't know the underside of the board and am starting to suspect some sort of contamination but would love some input before I dis-assemble it more.
Thanks for any help
I have a Boogie MK III Red Stripe on my bench with low gain in the Rhthym mode. When I engage the Rhthym 2 the tone thins out and the gain drops some more.
I have fixed hundreds of guitar amps but am not so familiar with Boogies, I have fixed less of them than any other amp. However, I have been digging for a while and am stumped. The LDRs and relays are all working best as I can tell. When in Lead mode the amp can be driven to full power but the Lead Drive acts funny. When I bring up the gain it jumps to full then starts to attenuate a bit. The pot is working fine - I can read the resistance of the wiper and if I disconnect the wiper from the lead gain stage the signal acts properly.
The tube amp stage all have gain. The weird thing about the Boogie for me is the Rhythm channel coupling to V2, where there is a big gain drop and filtering.
I suspect both problems are caused by the same culprit but all my readings don't point me in any direction. I have yet to remove the pc board since it's such a PITA and I was thinking a failed component would show up by now. I don't know the underside of the board and am starting to suspect some sort of contamination but would love some input before I dis-assemble it more.
Thanks for any help