Problem with LG Plasma 60PM6700 - Random power downs

[theone111]

I have an LG Plasma TV 60PM6700 for the past ~12 years.

In the last ~3-4 months I have been having some issues.

1. Problem: It started with random picture disappearing (sound still worked).
   Frequency: Happened about once a week.
   Solution: Had to turn off TV wait a few seconds before turning it on again.
2. Problem: Then it got worse and the TV started to shut down and when turning on the no picture just sound.
   Frequency: Happened about once a week.
   Solution: Had to turn off TV wait about 10-20 seconds and turn it on again to solve.
3. Problem: TV shuts down if AC in the room isn't on
   Frequency: Happened between once on hour - once a week. mainly depends on room temperature.
   Solution: Had to turn off TV wait about 10-20 seconds and turn it on again to solve. Turn on room AC.
4. Problem: "White" video image (see attached) after powering on after a random shutdown.
   Frequency: Happened once first time today.
   Solution: picture returned to normal without intervention.

A couple of weeks ago I removed the Power board (middle), Y sustain board (left), Z sustain board (right) and resoldered all MOSFET and coil solder points (some solder points seemed to be slightly cracked).
No capacitors look bulged.
No blackening spots on the PCBs.
Measured internal voltages (as appear on the sticker inside) Vs, Va, 5v are exactly as they should be when TV is working.

I also attached 4x DC outlet fans to the top outlet grills on the rear of the TV (connected to the TV USB ports - fans power on when TV is turned on).

Problems - mainly (3) - still happens.

I tried running the TV without the rear panel (to measure voltages when it happens) for a few hours without AC but couldn't reproduce the problem.

I think the problem is related to overheating but of what component?
What could be the problem? How can I continue to diagnose the problem?

This is my last resort before throwing the TV out - this is our main TV and the wife wants one that works

[Biruslapio]

Test without the mainboard using the logic board auto_gen.

I recommend always using energy saving on this TV to extend the life of buffer boards + Y-SUS.

[theone111]

Test without the mainboard using the logic board auto_gen.

I usually have an image, as I wrote below the main problem I am facing lately is that after some time the tv shuts down randomly and If I wait a few seconds it works OK again until the next random shut down.
As I understand the autogen is just to diagnose if there is a problem with the inputs and/or the main board. This is not my case as I understand it...

[Biruslapio]

With the main board out of the equation it cannot not trigger a shutdown.
If it still happens, control board or Y-Sus most likely, Y-buffers are also problematic in this model, but the picture would look strange, unstable at least.
Is VSUS still on when the image/panel shuts down?