GM D7400m

[Hexhclass]

This amp plays good audio but shuts down when input signal is increased.I think it is going in protect because I also lose drive to the PS FETs for a brief moment.

Any suggestions?

 

[Hexhclass]

.

 

[Perry Babin]

Was it working perfectly in the car and just started this all of a sudden?

Easy to recreate on the bench?

No intermittently shorted inductors?

 

[Hexhclass]

It’s happening on the bench.I don’t no the history the owner bought it used and realized it’s not working properly.
Inductor look ok but I will inspect it again.

 

[Hexhclass]

I install a next inductor for test and it is behaving the same way.

 

[Perry Babin]

How did you know which inductor to replace?

Next inductor?

 

[Hexhclass]

I thought the biggest one was the one in question,I did not even realize the two small ones were part of the output filter.

I guess I have to remove these and check them also?

 

[Perry Babin]

Twist/push/pull them while the amp is trying to power up to see if the amp changes its behavior.

L301 is the output filter.

There is corrosion on the metal grounding tab. Are the connections to the ground still OK?

 

[Hexhclass]

Yes some rusty.

I used a jumper wire to connect the grounds while the board is out of the sink.