The problem is that amp is in protect and draws a lot of current making the PS Fets IRF3205 super hot in a seconds. I've already removed the output mosfets.
Checked every small SMD transistor and diode. Everything reads fine, the only odd thing were these two small smd caps....
There have been previous attempts for a repair but they were unsuccessfull ones.
Now after replacing these small caps, i'll remove the IRF3205 and check the gate drive...
Checked every small SMD transistor and diode. Everything reads fine, the only odd thing were these two small smd caps....
There have been previous attempts for a repair but they were unsuccessfull ones.
Now after replacing these small caps, i'll remove the IRF3205 and check the gate drive...
Doubtful.
Disconnect it from the rectifiers and then test it for AC output.
You've got something wrong in the amp section.
Pulled out the rectifiers. Same. The problem is in the PS section.
There is almost no swing between 12v and ground, it's like they are turned on at all time. No pulling to the ground.
All the small SMD transistors near TL494 read fine. Checked them one by one as I did for all the gate resistors and pull down resistors.
I still bet my money it's short in the transformer due to the fact amp was mounted on the subwoofer box.
I can post a picture of the gate drive a little bit later.
There is almost no swing between 12v and ground, it's like they are turned on at all time. No pulling to the ground.
All the small SMD transistors near TL494 read fine. Checked them one by one as I did for all the gate resistors and pull down resistors.
I still bet my money it's short in the transformer due to the fact amp was mounted on the subwoofer box.
I can post a picture of the gate drive a little bit later.
Perry is always right. With no PS FETS = perfect gate drive. When they are in - amp is in protect and pulls as much current as it can, like something is shorting out, but the only thing which gets hot are the PS FETS.
Already checked each one of them - they all read fine.
Interestingly enough it's the same with or without rectifiers, it doesn't matter if they are installed or not.
Already checked each one of them - they all read fine.
Interestingly enough it's the same with or without rectifiers, it doesn't matter if they are installed or not.
The drive signal doesn't generally have a problem with the FETs in the circuit, even if there is a problem down the line.
Check the FETs for leakage from the gate to the other terminals.
Did you try loading the drive circuit with a resistor or small capacitor to see if it is OK?
If you suspect the transformer, try twisting/pushing/pulling it while powering the amp through a limiter with all FETs clamped to the heatsink to see if the current draw changes.
Check the FETs for leakage from the gate to the other terminals.
Did you try loading the drive circuit with a resistor or small capacitor to see if it is OK?
If you suspect the transformer, try twisting/pushing/pulling it while powering the amp through a limiter with all FETs clamped to the heatsink to see if the current draw changes.
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