Samsung PN43E450A1FXZA (Plasma) - Display up for 4 mins, then shuts itself down

[berriferous]

Set was manufactured in 2012. I'm trying to diagnose where the problem is. I am assuming it is over-currenting after heating up? Display looks fine until it decides to shutdown. If I keep turning it on, it will eventually refuse to power up and requires unplugging to get it to respond again.

I originally thought there would be some easily detected bad electrolytic capacitors, but I don't see the telltale signs. There might be some very minimal bulging on one of the x buffer board. BN96-22092A (LJ92-01852A).

If I unplug the power feed to the X/Y board (LJ92-01854B), the power supply seems to stay powered up until I chose to shut it down. Of course, maybe this is due to less loading on the system.

So looking for some ideas on where to start looking? Is the problem on the X/Y board? What's the best way to narrow the problem.

[Nugzzy]

For starters, here's a troubleshooting guide - hope it can help you out Samsung+PN43E450A1FXZA+Fast+Track+Troubleshooting.pdf

[berriferous]

I have measured VS = 209V, VA = 58, VSC = -185, VE = 99. These are the values shown on the sticker, but VE is not on my sticker.
I can get into the service menu. I ran through all the test patterns. MSTAR and Logic.

The system is not always shutting down, so something must be marginal. For instance, I ran the service test patterns in the diagonal scrolling grayscale for 15mins without issue.