2012 Samsung plasma, top half is black pn51e550df1

[geeforce]

Hello bad cap'rs!!

Newly acquired project tv... pn51e550df1.

Starts up fine, regular heartbeat. But top half of tv is black, you can slightly notice three varied shades of black for the top. Tried testing the IC on buffer for shorts on top, no luck.

I'm thinking it's maybe the y sustain board. Can I test the output to the buffers or something? The top pin for the buffer seems to have continuity between all pins which seems incorrect.

Anyone have any thoughts? Cheers!!

[jjanssen7]

Re: 2012 Samsung plasma, top half is black pn51e550df1

Sounds like an upper buffer to me.

[chrismurphy]

Re: 2012 Samsung plasma, top half is black pn51e550df1

replace upper buffer
check ysc on top buffer

[geeforce]

Re: 2012 Samsung plasma, top half is black pn51e550df1

Just took these quick videos... one just shows whats going on (half black screen), the other is me using a continuity tester on part of the buffer board... seems maybe failed?

Took some pics of things that said ysc - not sure what to test, there is a ysc and ysc con coming from the mainboard ribbon cable and then a resistor or something attached to a heatsink later on in the board.

https://youtu.be/myqhgCDyQVY

https://youtu.be/SCT67aFPFSQ

[geeforce]

Re: 2012 Samsung plasma, top half is black pn51e550df1

replace upper buffer
check ysc on top buffer

Here's some pics...?

[geeforce]

Re: 2012 Samsung plasma, top half is black pn51e550df1

Sounds like an upper buffer to me.

Do you know any local places to try for parts? Or pretty much ebay is best bet?

Cheers!

[jjanssen7]

Re: 2012 Samsung plasma, top half is black pn51e550df1

I can look and see if i have one... I'm only in chilliwack...

[geeforce]

Re: 2012 Samsung plasma, top half is black pn51e550df1

I can look and see if i have one... I'm only in chilliwack...

For sure, let me know! Waiting to hear back about a few on eBay yet...

LJ92-01871A is the buffer board.

[chrismurphy]

Re: 2012 Samsung plasma, top half is black pn51e550df1

your testing on the buffer for shorts is wrong

[chrismurphy]

Re: 2012 Samsung plasma, top half is black pn51e550df1

check all the group of 470 ohm resistors on your top buffer

[geeforce]

Re: 2012 Samsung plasma, top half is black pn51e550df1

check all the group of 470 ohm resistors on your top buffer

Ok! Should I be testing for a short? I'm super novice... I see the 470 chips though.

I did test the buffer chips by putting black to the svc_outl spot, then ran the red down both sides of the ribbon socket thing. No shorts were found there.

[geeforce]

Re: 2012 Samsung plasma, top half is black pn51e550df1

Well, I've got a y drive board on order... Wondering if I should have picked up the y main also to cover my bases... Wish me luck.

[Andrew F. Ali]

Re: 2012 Samsung plasma, top half is black pn51e550df1

Go for the Y-Driver Bd. first. Though it has been said in some quarters to replace the Y-Main and Y-Driver Bds together.

[geeforce]

Re: 2012 Samsung plasma, top half is black pn51e550df1

Some more pics...

It's weird that everything seems shorted on the plug highlighted in red. Not sure what that means exactly, does that mean the short extends to the y sustain also?

[Andrew F. Ali]

Re: 2012 Samsung plasma, top half is black pn51e550df1

Yes...

[attainteddragon]

Re: 2012 Samsung plasma, top half is black pn51e550df1

that entire connector appears to be ground plane, that is why it appears shorted.

[Andrew F. Ali]

Re: 2012 Samsung plasma, top half is black pn51e550df1

that entire connector appears to be ground plane, that is why it appears shorted.

Thanks. I didn't see that. Grateful.

[geeforce]

Re: 2012 Samsung plasma, top half is black pn51e550df1

that entire connector appears to be ground plane, that is why it appears shorted.

Need to Google that lol

[attainteddragon]

Re: 2012 Samsung plasma, top half is black pn51e550df1

first thing that i think that you need to do is remove the upper buffer board completely from the chassis.
in diode mode, place your red probe on that connector that you have just discussed, then rake your black probe down the pins that where the panel plugs into the buffer.
a beep is bad.
once you know which chips on the buffer are bad, you will be able to test the new one prior to installation.

it seemed to me that you were unsure of how to test them properly. let us know how you go.

[geeforce]

Re: 2012 Samsung plasma, top half is black pn51e550df1

Yes, I've done the test a few times now. Didn't realize the top connection was just ground essentially. There are no beeps... Makes me worried the fault is in sustain board.

Attaching some more pics of the sustain board, anything I should check before I plug a new y drive board in?