Is This A Power Supply Problem?

I have a PS4 here which if left for a while unplugged will turn on. But eventually once it’s been plugged in and when you turn it off, next time it won’t turn on. It will click, flash blue and click and power down again. I know that can be symptomatic of BLOD. But I have never come across this issue before. I’ve tried washers and cleaning out the PS4 / applying new thermal paste but it hasn’t helped.

Could this be a PSU problem opposed to an APU problem?

Thanks folks!