TV intermittently isn’t turning on

Hi all, am having an issue with this tv. Lately it doesn’t turn on when switched off. Doesn’t happen all the time, but when it does it can take 10-20 attempts to get started again - particularly from cold. If the tv is in use and is turned off, it comes right back on.

The tv works just fine otherwise.

I can bypass the issue by never turning it off (ie, I set it to auto-standby and it always returns from standby state no issues). But sometimes it does get inadvertently turned off!

I suspect a bad component (or solder) in one of the 2 power supply boards, so am considering swapping them out.

can anyone advise which of the 2 power boards is an ideal candidate for replacement? Or both? Or is it possible this is not a power-board related issue?

Thanks!