No audio output jl audio 500/5 troubleshooting

[Pbs64133]

After replacing the damaged resistor I get a reading, starting with the resistor closest to the pre-amp board
47.3v
14.7v
-14.8v
-47.3v

 

[Perry Babin]

Does the amp produce audio now?

 

[Pbs64133]

I have audio on all channels. The rear channels are dustorted with low volume. The amp seems to be power cycling. By "power cycling" At startup the low ohm led lights up then the power on led lights up. After 30 seconds has lapsed the amp shuts down then repeats the initial sequence. The drivers U112, U212 and U312 have all three LED's illuminated. U412 only has the top pair LED's illuminated.

 

[Perry Babin]

Have you resoldered the LED that's not lit?

 

[Pbs64133]

I will re-solder the LED and post the results

 

[Pbs64133]

Output transistor Q302 (it appears all outputs have been replaced)has failed and the gate resistor read its correct value. What should be the first thing I should check to find the problem?

 

[Perry Babin]

Sometimes the outputs fail without doing any other damage.

 

[Pbs64133]

I want to thank you for all the help. It has been a very educating experience and now have clear audio in all channels except the right rear which has no audio.