Samsung PS51E550 Plasma TV

[ArMaaN376]

Hello,
I am having Samsung PS51E550 Plasma TV. While the TV was working, a crackling sound heard & video went off with audio still ON. After switching it off & ON, the red LED on TV blinks six times & then off.
Opened TV cover & observed foll
a) Green LED on the small PCB blinks at @5-6sec ON & off for 3-4 secs. Red LED on logic board ON
b)Vs & Va on power supply board raises momentarily to 209v & 58v resp & then drops.
c) Cold test on Y-main board shows all 3 pins of FGPF4536 IGBT short to Grnd.
How to confirm Y -Buffer board ( connected between Y-main board & plasma screen ) is OK before replacing Y-main board with another ok board??
Pl kindly suggest.

[tvtimmy]

https://youtu.be/51SZsfH60EY?si=CFenhMcjxyXJjriH

[ArMaaN376]

Thanks for your kind feedback. I will definitely study it.

[ArMaaN376]

Tried by checking any dead short between Y buffer board input socket & the output socket of the Y buffer board as instructed in the youtube link using a DMM. Couldn't find any dead short.
a) Any idea of checking the supply voltages on the Y buffer board ?? their values & pinouts on Y buffer board?? So that it can be checked in the present fault condition so as to confirm that there is atleast no power supply short on Y buffer board???
b) As already mentioned, the Vs & Va voltages are momentarily generated to correct values at power ON to TV ( without switching ON the ON button on TV), but then the voltages slowly drop to zero ie probably board going to shutdown mode. Checked the 15V, 5V on the power supply board & are OK & remaining constant. As mentioned the IGBT on Y main board is found short.
I have now rec'd a Y main board from ebay. But before replacing it I wanted to confirm the main power supply board & Y buffer board are OK. I am also not sure whether the crackle sound heard before video going OFF was due to IGBT failure on Y main board.
c) Is there any method to check the power supply board after removing the Y main board from circuit ( just disconnecting the power cable plug (cable coming from X board to Y main board) is not sufficient as there is a flat ribbon cable ( for feedback & control signals) connected from Y main to logic board ????
d) Since 5v, 15v supply are constant & ok & also Va, Vs rising to their respective defined values before slowly dropping to zero, Can V conclude that main power supply board ( generating various supply voltages) is OK???
e) If anyone can pl kindly share his expertise so that I can replace the rec'd Y main board with the faulty one on the TV.
Awaiting for kind guidance.
Rgrds.