Crown I-T6000 Rare Failure

Hi,

I am in the repair process of one Crown I-T600 power amplifier but it have a very rare and strange problem. This amplifier sound for 1 second(literally!) and after that it mute itself after the turn it on. I have added a short video showing this issue and I will be very grateful if someone can help me in order to find what the problem is.

WeTransfer

I will wait for any comment, advice or suggestion in order to try to repair it.

Thanks for anticipated help!
opacheco.