Kicker ZX750.1 Powers Up (green Light) No Sound

[bigpun4fubu]

This powers up fine, relay kicks in also I play a test tone thru it and it passes thru the preamp board fine but cannot seem to figure out why no sound, i have checked all the fets and regulators and they seem ok maybe I am checking them wrong, someone help me if you have some knowledge of any of these symptoms

[Perry Babin]

Is the center leg of all of the output transistors at ~0v when the amp is powered up (black probe on negative speaker terminal)?

Do you read approximately either positive or negative 70v on the 3rd leg of all of the output transistors?

Be very careful not to short the probe to the clamps while measuring the voltage.

[bigpun4fubu]

3rd leg being on the right or left?

[Perry Babin]

See attached.

[bigpun4fubu]

thank you ill check

[bigpun4fubu]

.002 ~V on center leg

[bigpun4fubu]

55.3 Vdc on 3rd leg on each my power supply is kind of weak , it does right at 11.9 to 12 v

[Perry Babin]

Did you have negative 55 on some of the outputs?

[bigpun4fubu]

on one i did yes

[Perry Babin]

All of the IRF640s should have -55v on the 3rd leg. All of the IRF9640s should have +55v on the 3rd leg. Recheck.