Orion xtr2150 amp

Hi, I have a orion amp that the pwm will not fire up. I have 12.44 volts on the left channel and 10.4 volts on the right channel. I have checked all the MOSFETs in the power supply, all ok. I have checked all the outputs and one was shorted and I replaced it. I have checked the comparators and even replaced the pwm IC. Any other suggestions?

Thanks,
Jim