Anyone Know the Cello Duet 350?

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Hi All,

Anyone here have experience with servicing one of these beasts? I have one here that was decimated! Literally went on fire, I have completely re-semiconductored it literally - EVERY transistor in both sides was shorted), recapped it (all electrolytics were way out of spec), replaced melted wire, and burned / open resistors. The result. in short - Nothing! Doesn't blow fuses any longer, one side has high d.c. offset, (that can't be nulled with the offset pot on the va board), and the other none, but, most importantly, I get NO audio from either channel. All of my supply voltages seem spot on (as far as I can tell), schematics for this amp seem to be as rare as rocking-horse ca-ca! What throws me is that rear-panel protection board, can't say I really "get" what they're doing with that. What I was wondering, if anyone knows this amp, is it ok to disconnect that board from the main amp channels, and run some tests on the channels, with the protection out of circuit? Any assistance that the esteemed denizens of this board would be willing to lend, would be supremely appreciated!
 
Hi All,

Anyone here have experience with servicing one of these beasts? I have one here that was decimated! Literally went on fire, I have completely re-semiconductored it literally - EVERY transistor in both sides was shorted), recapped it (all electrolytics were way out of spec), replaced melted wire, and burned / open resistors. The result. in short - Nothing! Doesn't blow fuses any longer, one side has high d.c. offset, (that can't be nulled with the offset pot on the va board), and the other none, but, most importantly, I get NO audio from either channel. All of my supply voltages seem spot on (as far as I can tell), schematics for this amp seem to be as rare as rocking-horse ca-ca! What throws me is that rear-panel protection board, can't say I really "get" what they're doing with that. What I was wondering, if anyone knows this amp, is it ok to disconnect that board from the main amp channels, and run some tests on the channels, with the protection out of circuit? Any assistance that the esteemed denizens of this board would be willing to lend, would be supremely appreciated!
Hi Did you ever get anywhere with this amplifier? We have a client with one that is blowing fuses pretty regularly and wondering if the amp is failing. It does work well when operational. Thanks
 
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