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does anyone have a CM Labs 911 Schematic

does anyone have a CM Labs  911 Schematic

Hi anyone I´m looking for a CM Labs model 911 Schematic,
 any help will be Great!--
 I cant seam to find one or a CM Laboratory   911
I have a 2v dc off set problem I think it should be 0v.
I checked all caps and resistors all ok I just replaced the main B+ caps
unit works OK but for the 2v dc on both sides of the speaker outputs that I  cant adj out 
also the balance and bias controls are wire wound pots I am wondering if I can 
get away with 1 watt or smaller on these controls?

madman2000
madman2000 OP
4 posts
 
ok I get 8mv with a 8 ohm load but balance adjust doesn't do much stays at 8mv also 3v across ? ohms on wire pots = ? wattsalso what points do I measure bias adjust from and what are they set at ?
imhififan's avatar
imhififan
2,179 posts
 
The 8mv from the output is due to the leakage current of the output capacitor, I think your amp is over 40 years old so best to replace those caps.
The 911 is a single rail power supply, output capacitor coupled power amplifier, I don't think you can adjust "DC offset" on this amp. I believe the "balance adjust" pot is to adjust the voltage before the output capacitor (at the + side of the cap) for max output without clipping, in most case is half the value of the power supply rail voltage.
It's best to obtain a service menu for bias and balance adjustment.
Good luck
madman2000 OP
4 posts
 
Thank you very much that solves the wave form balance problems
also I have a good schematic now but it does not show the wattage of the pots 
or  where to get and how much bias voltage should be.
I may have to buy the schematic and hope it is in there.
I never could get a answer from Mr Wayne Chou I hope he is OK.
and he is just a busy guy.
thanks again.

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