Hi all , I have a monitor audio powered sub AW-12 which has an issue , the issue im having is it won't come out of standby , the led started flickering between green (active) and red (standby) now just stays red , I've ruled out the input end and suspected the mosfets on the output stage (FB59N10D) causing it was staying in protected mode but these tested ok ..
I was going to do some voltage tests but the way the boards are held together , the heatsinks for the transistors make it impossible to get to the boards when its assembled , is it a no no to power the boards without the transistor heatsinks attached even when no input signal is added ? .
Ive attached some photos the green arrows are the mosfets which tested ok .
I was going to do some voltage tests but the way the boards are held together , the heatsinks for the transistors make it impossible to get to the boards when its assembled , is it a no no to power the boards without the transistor heatsinks attached even when no input signal is added ? .
Ive attached some photos the green arrows are the mosfets which tested ok .
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I thought i was making progress on this project , apex sent me schematics for 2 of the boards but not the audio output board , the voltages to the output board all seem ok , i noticed when i moved the coil (see photo) the led flickerd red / green , so investigating around that area i found the capacitor circled was giving no reading , it is a 10 uf 50 v NP . I replaced it with a 10 uf 100 v NP .
I have also replaced the relay in case it was the problem , i had been getting the relay intermittently clicking and led turning green .
The problem seem to be no 12 volts getting to the relay . any ideas anyone ?
I have also replaced the relay in case it was the problem , i had been getting the relay intermittently clicking and led turning green .
The problem seem to be no 12 volts getting to the relay . any ideas anyone ?
Sounds like it might be a bad signal detector. Does the sub auto off and on with input signal? If so this might not be working. What drives the LED?
The cap you replaced probably is in the output filter by the looks of it... Class D sub amps like to be cooking those. (Do you find any others? Or bad solder joints?) Something else watching out for is fried feedback resistors. The relay might not be engaging because of overly high DC offset as a result.
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