Random Shutdowns. Unplug - Replug to start up

Hi there.

My 27” iMac 5K (A1419) has just started shutting down randomly. I did a terminal test and it looks like an SMC issue. Issue numbers all 0.

I reset the SMC to no avail.

Everything points to power supply failure but is there anything else I can check or reset before I replace it?

Thanx