Samsung PN58B650S1FXZA Plasma

Thread Starter


Joined Jan 24, 2012
I have a Samsung PN58B650S1FXZA Plasma TV I got from a friend that he said he was watching one day and it just quit;

Found the Y main Board fuse blown which later was diagnosed to be a considerable number of blown (shorted) MOSFETs.

It was more economical (about $35 in parts and quicker) to buy a new Y-Main Board. Originally went looking for a used board but I found by accident a New-Old-Stock board (originally from Samsung) from a local fellow who is closing (closed) his TV/electronic repair shop. Cost was about $20 more than parts.

Shipping on this dusty box said it came to him in 2011....Board looks signs of heat or ever being used.

Part Number BN96-09758A...The only difference I see in my board and the new...Its revision is 1.3 and mine is 1.2 date is less than months difference between boards. Everything else including PCB and PBA Numbers/silk screening is the same.

Tested the Y-Buffers similar to the below video;

Did not see any issue with the Y Buffers.

Anyways then I put in the new YMain board.

Unfortunately no dice on the TV coming back to life.

So I started taking Voltage readings;

Panel Label says for reference.
Va -> 55V
Vsc -> -190V
Vs -> 202V
Ve -> 95V

CN801 Power Supply Tests
VS_ON and PS_ON both test 3.3V at appropiate times and go to 0V Otherwise.

After TV not in Standby point and warmed up to assumed On (10-15Mins)

Power Supply

Vs @Point Test -> 202.9V
Va @Point Test ->55.0V

YMain Board Tests

Vs @wire Connection (2) -> 202.9V
Vs @Removal Fuse Points (Both Sides) -> 202.9 V
Vcc @wire Connection -> 15.0V
Vscan @Point Test -> -197.3 (Should be -190V ...I wonder if this needs to adjust?)

XMain Board Tests

Vs @wire Connection(2) -> 202.9V
Vcc @wire Connection -> 15.0V
Vb @Test Point ->108.5V (Seems higher than Panel Label wonder if I should adjust to 95V?)

LED on TCON is flashing about 1 a second maybe a little faster.

I then Tried the process marked out in the below YouTube video about Troubleshoooting and Test Patterns.

Test pattern process (shorted ps_on pin, Main board disconnected from Tcon LVDs cable, and 3-4 pin shorted) but still no life in panel.

Not sure where I should go from here...Ideas or Suggestions?

Thanks everyone,

Thread Starter


Joined Jan 24, 2012
Well I will answer my own question...Basically even though I tested for shorts on the Y buffers I started to question the fact that the panel did not light and it had to be in the boards other then the Main Board (As its out of circuit in a Pattern Test). The TCON (rarely goes bad), the Y MAIN, Y Buffers, and/or XMain. The Y Main was brand new (OEM new) so it was doubtful. The XMain or the Y Buffers. As the Y Main alot of times takes out the Buffere... I decided to take each of the Y Buffers out separately from the Y Sustain board and test the system again. This time the Lower Y Buffer once removed the Upper Buffer worked with the Panel and lit the top of the Panel.

I retested my Lower Buffer for Shorts and now they are I either missed it or something went bad since the new Y Main was installed.

Ordered another Y Buffer...hopefully this will get the TV up and running again.