"the protection circuitry has been activated three times consecutively. When the unit is in this condition, the standby indicator on the unit blinks if you try to turn on the power....REMEDY: As a safety precaution, capability to turn on the power is disabled. Contact your nearest Yamaha dealer or service center to request repair."
here from google:
Connect power cord to mains and wait 5 seconds or so. While holding down "info" and "tone control" buttons, press "main zone" power button briefly and release, but keep "info" and "tone control" buttons pressed for at least 3 more seconds. The unit should power up. Assuming the reason for the protection has passed or been fixed, the unit can now be turned off and then back on with the "main zone" power button to restore normal operation mode.
If the protector activates again, the fault is still present and the unit needs to be repaired, ideally by a Yamaha authorised repairer.
There are dangerous voltages present in high power amps and a lot of grunt in terms of stored energy - best left to trained technicians.