Samsung UE40J5100 Blue threads in picture

[JPElectronics]

Samsung 40" LCD originally had no picture - I repaired that fault by replacing the T-Con (RUNTK 5538TP ZA).

With the new T-Con the left hand half of the screen now shows what I can only describe as 'dynamic blue threads' which appear when there's any blue content in the picture. The right hand side is not affected. The attached photos show what's happening.

Could my new T-Con be faulty? - it arrived from China wrapped in non-ESD (antistatic) bubble-wrap which is a concern.

I've searched this forum but haven't found a similar fault mentioned - I hope someone here may be able to throw some light on this.

Many thanks in advance, John.

[nomoresonys]

Re: Samsung UE40J5100 Blue threads in picture

I don't know for sure but I think you got a bad one.

[diif]

Re: Samsung UE40J5100 Blue threads in picture

Have you checked the flat flex and connectors ? If you can't see any damage, try rotating the cable and see if the colour changes.

[JPElectronics]

Re: Samsung UE40J5100 Blue threads in picture

Thanks for the suggestion Diif but unfortunately no difference to image after rotating the LVDS cable, I also gave the connectors a good spray with board cleaner to no avail.

So it looks like nomoresonys wins this round.

If the TV was mine I'd just go ahead and order another T-Con but I'll have to leave that decision to the owner.

[dick_barton]

Re: Samsung UE40J5100 Blue threads in picture

That looks a little like a solarized picture which you wouldn't expect with a replacement tcon. Measuring the VGx voltages on the Tcon may give a clue as to the problem.

What is LVDS_SEL written on the tcon. Can you post sharp focused picture of the two tcons to compare

[JPElectronics]

Re: Samsung UE40J5100 Blue threads in picture

Thanks for your help, DB.

VGH = 32.4V
VGL = 6.0V

LVDS_Sel = 0V (So LVDS data format = JEIDA)

[SoftwareHack]

Re: Samsung UE40J5100 Blue threads in picture

I'm no expert, just an observation, but on the new board there's a pin on the right hand ribbon cable just to the right of center that doesn't appear to be connected compared to the old board.

[JPElectronics]

Re: Samsung UE40J5100 Blue threads in picture

I was hoping an eagle-eyed sleuth like yourself may be able spot the problem but that pin buzzes out ok between the pcb track and the pin side of the connector.

Even so - many thanks for your help, S/W Hack!

[dick_barton]

Re: Samsung UE40J5100 Blue threads in picture

Is VGL +6V or -6V. I think VGL is normally a negative voltage.

[JPElectronics]

Re: Samsung UE40J5100 Blue threads in picture

Yes, VGL is -6V