Have this receiver for about 7 years, never was a single issue. Yesterday after turning PS ON played 10 minutes, then receiver turned off. Tried various suggestions to reset, keep unplugged, disconnect all speakers, nothing helped. The standby light blinking, after multiple attempts to turn receiver on once in a while getting error CHECK POW5. WAIT, then turns off again. Would appreciate if someone could recommend the solution. Sounds yo me like it has to be repaired by experts. Thanks in advance!
If the receiver powers itself down when there is no load (speakers) on the outputs and no input sourced, then likely you will need to have the unit repaired or replaced. Contact Marantz with your problem, possibly there's a factory reset you can try before you decide to take further action.