What does this Error Message mean?

Hello AuburnCE, After 4 years of joy my Marantz SR8200 receiver also shows this message from time to time - after 1h of operation or so. Then it is hanging (like a PC ;o). Taking it of from the electricity network for a moment resolves the problem until the next POW 05 hang usually a fiew days later. I brought the receiver to an authorized Marantz maintenance and repair center twice now and they were not able to reproduce the error. They said this has directly or indirectly to do with the power supply unit. They also called marantz. For me it appears that this is not an internal receiver problem IN MY CASE. I think I there might be a relationship to zapping on my Topfield SAT receiver via power supply network as the connection is optical. Or my dimmerunit for the light. Unfortunately I do not have a separate electric circuit for Audio/Video and all other electrical devices. and dimmer units are well known to cause problems in the power supply chain - e.g. like noise in your audio package. Please note: the experts told me: Check POW 05 can have other (receiver internal) causes also. Above is just my suspicion 8as a non-expert) for my case . Regards, Fred