Yamaha rxv-657 goes to protect. Help!

[strat1953]

its turn on then goes right to protect.i changed c405 but did not fix it. i also checked all the amp section transistors and the amps fine.if theres a yamaha tech that knows what or where the problem is or where to look,i will gladly paypal you  to repair advice. you can also text me 480-703-9586 or email strat1953@aol.com thank you. i also have a 757 with the same problem

[mzacharias]

Do you have the service manual and know how to use a multimeter?

Most shut-downs on Yamaha's relate to regulated power supply issues (bad voltage regulator like a 7805, 7812, 7912, etc) or a DC offset on a single channel.

Blown amplifier channels cause a much faster shut-down, so fast the display never lights up, and you only hear a quick single click.