POWERNODE N150 - No LED, no WiFi, no Bluetooth. Is it dead?

My Powernode N150 has no LED indicator. I turn it on, after almost 30 seconds I get a click. That's it. No LED to indicate status. I turn it off and hear the same click, as if a relay has operated.

The Powernode has always been a bit unstable, losing its WiFi connection or having to be reset to factory settings. I have two Bluesound Nodes as well, so I'm well aware that they sometimes get screwed up with firmware upgrades. This problem is more than the usual Bluesound problems. The Powernode N150 has been falling asleep over the last year or so, not always keen to wake up. I've begun using it less as it can take half an hour to get it working, which spoils the mood for music.

Now it's dead. Besides the click at 30 seconds there's no other inidcator of life. I get no WiFi signal from it. Because of the connectivity problems I've had over the years I often find it easier to use Bluetooth. If I plug in my (approved) bluetooth adaptor I don't see it anymore.

I tried a factory reset but without a LED indicator I can't know if that was successful.

I downloaded the most up to date firmware (3.20.25) into the root directory of a 32GB USB drive, formatted FAT32. I plugged the USB drive into the N150 and tried to reboot off that USB. Without an LED indicator all I could do was wait 30 seconds for the click, then about 6-8 seconds more before releasing the mute button

Help please. I'm loathe to junk a good amplifier. Surely the N150 hardware wouldn't just fail. It's only 8 years old and has no moving parts. A simlarly priced amplfier would be expected to last for decades. In fact, until I can get it working again, I'll be using a Node N100 with an original 1974 Sansui amp in its place.

Any suggestions?