Roofus , Jp1208
I too have an Amp 5 with identical problems .
I did the same thing (removed all cabling), it will power up without going into protection mode but as soon as I reinstall the cabling , it will not go into a standby mode .
Fearing it was speaker or cabling shorts I threw in a Rotel 5 channel amp , no problem . Tried other power cords , removed line conditioner ...no go .
This took place after doing it a couple of times , once during a movie and once left idling in standby . I was able to restart it those 2 previous times by pulling the power cord and waiting a few minutes ( like a reboot)
I took it to the Levinson shop yesterday and the tech was able to start it with no load . We did not get into it any further as he's quite busy but promised he would call Harman to see if this was a common problem . The serial number is 1011.
Short of paying 800 repairs for an amp worth about 1800 on todays market , I would love to hear of a remedy that does not require transporting this 110 lb beast and in turn if I hear of a solution , I would be more than happy to share it.
It'd be really interesting to hear from others , especially if this is an ongoing problem .
Hopefully there is a cure without major freight and repair costs . It's too bad as the Proceed gear sounds wonderful .