Q835 was shorted along with open gate resistor. Removed these components to test for gate drive and there isn’t any.
When grounding Pin 1 of U800 gate drive appears. Does anybody know what U800 is monitoring? Pin 3 on U800 is at 5 volts which makes Pin 1 go high not allowing U801 to produce gate drive.
There are no shorted mosfets in output section.
When grounding Pin 1 of U800 gate drive appears. Does anybody know what U800 is monitoring? Pin 3 on U800 is at 5 volts which makes Pin 1 go high not allowing U801 to produce gate drive.
There are no shorted mosfets in output section.
DCV on all terminals of U800 without pin 1 grounded?
Pin 1:
Pin 2:
Pin 3:
Pin 4:
Pin 5:
Pin 6:
Pin 7:
Pin 8:
Pin 1:
Pin 2:
Pin 3:
Pin 4:
Pin 5:
Pin 6:
Pin 7:
Pin 8:
Pin 1: 5 volts
Pin 2: 2 volts
Pin 3: 5 volts
Pin 4: 0 volts
Pin 5: 5 volts
Pin 6: 2 Volts
Pin 7: 3 volts
Pin 8: 12 volts
Pin 2: 2 volts
Pin 3: 5 volts
Pin 4: 0 volts
Pin 5: 5 volts
Pin 6: 2 Volts
Pin 7: 3 volts
Pin 8: 12 volts
Resistance between pin 3 and the two terminals of the 0.1 ohm resistor?
IT's also odd that pin 6 is at 2v without the low-voltage supply in operation.
IT's also odd that pin 6 is at 2v without the low-voltage supply in operation.
Ok, I replaced the resistor turned the amp back on and it took out the logic level mosfet. It was a STP45NF06. It wasn’t original but seems to be comparable to the original. The original is now obsolete.
It could be a couple of things...
The transformer could be shorted
The LM393 could be defective and not shutting down when there is an over-current condition.
It's also possible that something on the output side of the transformer is shorted.
The STP45NF06 isn't logic level. It may work for a while but will likely run hot and fail.
The transformer could be shorted
The LM393 could be defective and not shutting down when there is an over-current condition.
It's also possible that something on the output side of the transformer is shorted.
The STP45NF06 isn't logic level. It may work for a while but will likely run hot and fail.