Samsung PS-50P91FD Plasma repair help, sound and glow, no test pattern

[Recyclojunk64]

Hi, I'm trying to repair a 1080p Samsung plasma display, PS-50P91FD.

It turns on and makes the startup sound, then primes the display with a flicker and continues glowing faintly. Sound input works. Makes 5 flashes of the red LED then stops flashing (off).

Vs, Va and Vg are correct. Didn't test Vsc. All fuses I could find (glass and poly) were fine. No obvious damage.

I shorted pins 3 and 4 on the four-pin square vertical header on the control board, and removed the LVDS cable from the control board. There was no test patterns, just the same glow as before.

I read on another thread that it may have been pins 1 and 2 on certain control board models, so I tried shorting those two instead, just to be sure. Upon plugging it in, it acted as if it were completely dead. So I removed the jumper and replaced the LVDS cable.

However, upon plugging it back in again, it was still completely dead, while the power supply continued to make it's usual hum/whine. All power supply voltages except PS_ON (2.6v) were missing, and the green LED power supply light was off.

So now I suspect that the control board is damaged in some way (or perhaps bricked?) as the PS_ON signal goes only to the control board. Not sure though if the control board was the original source of the problem, or perhaps it was the X buffers/drivers. Would have been nice if I could have checked the for signals coming from it with my o-scope first though before now.

So would it be worth ordering a new control board for $40? Or is it more likely that the original problem was in the X buffers and it's a lost cause?

Thanks for any advice