Samsung LN55c650l1fxza Every 4th pixel is black

[Gftgrill]

Hi, I found this site while trying to research a problem with our TV. I was hoping someone here might be able to help me determine if we have a bad panel or a bad board in the tv.

If you get up close the display you can see a clear pattern running horizontally across the screen. Every 4th pixel is black. 3 on then 1 off.

These pixels do not always stay off, while watching the screen will go into a "glitter" state where these black pixels will start turning on and off randomly in random colors. sometimes it's a few pixels doing it, while other times it's most of them.

Please see the attached photos to see the symptoms that I'm trying to describe.

Thank you for any help you're able to provide.

[awyatt2]

Re: Samsung LN55c650l1fxza Every 4th pixel is black

left to right is usually buffer board up and down usually screen related, the electronics on the ribbon cable or tab bonds.

[mmartell]

Re: Samsung LN55c650l1fxza Every 4th pixel is black

Take the back off and snap a pic so we can see all of the boards and how they are connected to each other then we will try something.

[niblettr]

Re: Samsung LN55c650l1fxza Every 4th pixel is black

If I were to put money on it, I would say the control board as that interfaces with the X portion of the screen. It also has a fairly large BGA chip in the middle of the board. BGA chips when not heatsunk or heatsunk properly tend to crack the solder joints beneath it.

I have repaired a few of these boards in the oven. Its hit and miss (although I have had far more hits than misses.) I inject liquid flux under the BGA and on the bottom side of the PCB where the BGA is, preheat oven to max temperature. Put a blob of solder on the BGA chip as an indicator that oven is hot enough and leave in the oven for 10 minutes or for a few minutes after the solder on the IC has melted.
When done, remove from oven and board is ready to try within 10 minutes.

If doing an AV board, watch out for the scart sockets! They melt lol

I have never caused more damage than good using this method. (expect for the odd scart connector melted) Lost count of how many HP DV9000 laptops I have resurrected using this method.

See attached picture of control board after being in the oven, note melted solder on top of IC.

[mmartell]

Re: Samsung LN55c650l1fxza Every 4th pixel is black

Except this can't be a control board or a buffer board problem as this is an lcd and not a plasma.

Take the back off and snap a pic.

[niblettr]

Re: Samsung LN55c650l1fxza Every 4th pixel is black

'p' ooopps, sorry. Didn't notice that. I know nothing about LCD Tvs.
So, an LCD TV does not have an equivalent T-con board?

[niblettr]

Re: Samsung LN55c650l1fxza Every 4th pixel is black

see attached.

[ReeceyBurger123]

Re: Samsung LN55c650l1fxza Every 4th pixel is black

Haha this isnt plasma, I would say tab bond or tcon gammar or some stupid fault. What test equipment do you have ?

[Gftgrill]

Re: Samsung LN55c650l1fxza Every 4th pixel is black

sorry, for the late response all.

I was going to take the tv down, but I found that I can jiggle the HDMI connector at the port or unplug and replug the HDMI cable and it will fix itself.

I have tested this with different HDMI cables and I get the same result. change inputs won't fix the issue, I have to physically touch the HDMI cable to get the screen to correct itself.

the only testing equipment I have is a multimeter. I'm not very skilled in testing individual components on a circuit board.