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Tim Nolan
Tim Nolan, TV Repair Technician
Category: TV
Satisfied Customers: 19454
Experience:  Factory trained TV repair technician. U.S. NAVY trained.
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I have horizontal lines running across my Samsung 50" plasma

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I have horizontal lines running across my Samsung 50" plasma TV. Does replacing the ASSY PDP MODULE P-Y-MAIN SCAN BUFFER fix this problem?
Thank you for posting your question on Just Answer! I will be happy to help you with this problem. Can you please give us some more information so I can better answer your questions.

-Are the lines only on the top or bottom half of the screen?
-How old is the unit?
- Do you have this problem while watching all different devices hooked to this television? (DVD player, cable, satellite, game counsel, etc.)

Please give me this information and I will be happy to assist you further.

Thank you,
Tim Nolan
Customer: replied 5 years ago.
Lines are on both the top and bottom of the screen.
Unit was built January 2008 in Mexico. I forget when I purchased it.
Yes the problem never goes away. I see it with antenna reception as well as VGA / PC viewed videos.
My manual is showing this tv as having a upper and lower y buffer, you are saying you have one y buffer that goes all the way from the top to the bottom/

Customer: replied 5 years ago.
No there is a upper and lower board, 2 boards not one.
Ok then it would be unlikely that the buffer is your problem. Can you get me a picture of the problem? (if you can post a picture, please click the icon above, where you are typing, of the paper clip. This will allow you to upload a picture)

Customer: replied 5 years ago.
Customer: replied 5 years ago.
OK I sent you a photo of my whole screen showing the lines at the top and bottom. There are a few in the middle as well.
Very interesting, if you push the MENU button on the tv, does the menu show in front or behind the lines?

Customer: replied 5 years ago.
Behind the lines. The lines go across the menu. Obviously this is a hardware driver problem. I just want to make sure I replace the correct board.
Customer: replied 5 years ago.
This has been getting progressively worse. It used to be just the top of the screen. More lines are apperaing as time goes on.
In the picture i see the small lines that are going across the screen but then I also see the blue background split into several wide blue lines, is that a symptom of the picture or is that part of the problem?

Customer: replied 5 years ago.
I believe its due to the DVD player. I don't see them when I switch to TV with no antenna attached. Then I get a black screen with white lines going across it. What I need to know is it caused by the Y main scan high, Y main scan low or Y driver board? There are three boards than can be replaced.
Trust me if I could tell you right up front what was wrong with your tv I would, its not as simple as you are making it out to be.

Its definitely not the y upper or lower buffer boards. It may be a bad y sustain board though, however it could also be a logic board or a x sustain board.

I need you to do another test. What I need is for you to feel the metal heat sinks on both the y and z sustain boards while the tv is on, is every one getting warm on each board?

Customer: replied 5 years ago.
OK I have one of those laser pointer thermometer guns. It shows between 98 to 104 on each of the upper/lower scan boards. None of the heat sinks are particularly hot. There is a chip on the main logic board that is 120.
I need you to test the heat sinks on the y and z sustain boards, not the scan boards.

Can you get me a picture of the tv with the back off so I can mark on it?

Customer: replied 5 years ago.
The X-main heatsinks have gone up to 132 degrees.
I don't see a Z board in the service manual. Only x and y boards.
I have the exact Samsung service manual for my unit. You can get the PDF file at:

This covers both the 42 & 50 inch models.
z and x are the same thing.

What are the heat sinks on the y sustain doing?

Customer: replied 5 years ago.
They are under 100 degrees.
By the way this is just $14 per session and not $14 per minute or per hour isn't it?
Its per session.

But it does look like you have a bad y main board here, that is what I would be replacing in your shoes.

Tim Nolan and 3 other TV Specialists are ready to help you
Customer: replied 5 years ago.
OK I see there is a rebuilt one on line for about $35. I'll try it first.
Sounds good!