With a power outage, there will be an initial surge when the power comes back on. This may be enough to overwhelm a standby power circuit. A standby power circuit gets the AC voltage all the time, if the main power switch in the back is switched on. There should be a surge protector component in the incoming AC circuit. But these components can only take so many surge hits before they become ineffective. The surge protectors have so many "joules" of protection. Once these are used up, there is no more protection and there'll be no way to know this. All your other devices must still be protected, but perhaps not for the 2150. I'm guessing a failure of the standby power circuit in your case. A failure in this circuit will prevent the 2150, or any device with a standby power circuit failure, from powering on.