Memphis mojo 4kw

Can anyone give me an idea how the output drive works and what parts are involved with it on the main board.
The amp powers and relay engages.All power supply/regulators seem to be working.
Outputs are installed but no oscillation.It did have some shorter outputs.
I'm not exactly sure if there are driver transistors on the main board.Its a little tricky to trace because it's multilayered.
Also the rectifiers marked 30EPF06.Whats there purpose in the circuit?
 
QA1, 2, 3 and 4 are the driver transistors for the output stage. All of the drive is produced on the driver board, passes through those 4 driver transistors and then to the output transistors.

Those diodes are likely used to route any voltage/energy generated by the output circuit (the voltage that causes 'bus pumping') around the output transistors. Someone should correct me if that's not correct.