Samsung QE50Q60TAU - Horizontal screen lines

[Runlinc]

Hi everyone, the tv was in a continuous reboot cycle. To get the best screen image i can I taped the VGH and VSS pins on the left side buffer board joining ribbon.

I am left with a good image apart from the black horizontal lines that I cannot get rid of.

I cannot find anything on the buffer boards that has shorted.

Do you think there is anything i can do to eliminate the lines, or are they caused by an internal panel short and the image cannot be impoved.

Many thanks for your assistance

[Diah]

shoe clear photo of the the effected side buffer boards to check if there are ESD diode

[lotas]

They are located only here.

[Runlinc]

Hope these are a little better

[Diah]

did VGH below 27V??

[Runlinc]

yes Diah, the VGH is 24.9V

[Diah]

yes Diah, the VGH is 24.9V

for me its low for VGH rail diode 33C.it tested good but the problem will be at the minimum V. so the response in ms will be higher than it should 0.8ms . t-con on MB will response faster to shutting down.there are several reasons need to start from MB caps / regulator to Panel buffer boards in case VGH are high when panel unplugged.

[Runlinc]

Thank you so much for your reply.
i am checking and will post my findings.

[Davi.p]

Some spare lines indicates there are several shorts on the row drivers, probably integrated to the glass, the only mode i can suggest you now (to be short) is a method i used once long time ago, and is a short killing method..

[Runlinc]

Sorry for the delay in responding, I’ve been very confused.

I disconnected the Panel buffer boards but still only had 25v max output from the MB. I rechecked the buffer board components again with a newer multimeter but did not find anything amiss.

As a last resort i reconnected MB to the buffer boards without any pins being isolated. I was going to use Isopropol to coat the chip on the left hand buffer board to see if it was heating up during the start up procedure as I don’t have a thermal camera.

Switched on and it started up without any issue with a good picture !!!!
I have restarted it several times and ran it for an hour, with no problems.

I now have a working tv with a good picture but have no idea why. (I hope it starts ok tomorrow)

Many thanks for all your help guys.

[Davi.p]

Clean well the lvds cables connectors with isop.

[Diah]

Sorry for the delay in responding, I’ve been very confused.

I disconnected the Panel buffer boards but still only had 25v max output from the MB. I rechecked the buffer board components again with a newer multimeter but did not find anything amiss.

As a last resort i reconnected MB to the buffer boards without any pins being isolated. I was going to use Isopropol to coat the chip on the left hand buffer board to see if it was heating up during the start up procedure as I don’t have a thermal camera.

Switched on and it started up without any issue with a good picture !!!!
I have restarted it several times and ran it for an hour, with no problems.

I now have a working tv with a good picture but have no idea why. (I hope it starts ok tomorrow)

Many thanks for all your help guys.

when expected V go lower than usual, always will be no defect parts. but value change at parts. with yours checking on VGH circuit on MB, you had discharged parts which they were under charging.
try after you watching TV, turn it off completely from the wall cord. this will help to start again next day.