American bass

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Pin 1 drives the MAX transistor through a 100K resistor (R45?). With 0nly 0.3v on pin 1 of the LM393, there's no way that it could turn on the MAX transistor so it couldn't pull down the shutdown pin.

With no power applied, what is the resistance between pin 2 of the IRS21844Ss and your reference, pin 9 of the driver board.
 
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There most be a loose connection on the driver board,
Mute transistor is now off and PIN number 2 of 21844
is high at about 3.5 volts.
I install a new 21844 IC on the driver board and
Injected a 100 hz signal at the RCA jack and monitor
PIN number 7 of 21844 IC and have a 100 hz signal.
With some gain on it.
Any suggestion on this intermittence?
 
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For future reference...

Pulling Q10 (MAX) off of the board was safe because the LM393 wasn't driving pin 1 high. In most instances, when the MAX transistor is pulling the shutdown pin low, it may not be safe to remove the transistor because there may be an excessive current draw condition (which could destroy the output transistors).
 
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There is 5.3 ohms between these pins.
Also I will like to mention that again my
Hantek scope seems to be the cause of
the problem, Because when I use my
Fluke scopemetter it work without
intermittence. It looks like the hantek
Is sometimes overloading the signal.
Is it posible that my hantek needs a isolation
Transformer? because many times it just
Don't work using the 12v power supply
Ground, if not what can I do to correct this
Problem?
 
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