LG LCD 47LM5850 Contrast/Picture very white

[tech2014]

I have an LG LCD Tv that has a picture problem. The picture is very bright white, possibly a contrast problem. Would the T-CON be responsible for this or the main board? See pic of screen below.

[budm]

Re: LG LCD 47LM5850 Contrast/Picture very white

Looks like bad GAMMA ref Voltages on the T-CON. Pictures of the T-CON BOARD?.

[ReeceyBurger123]

Re: LG LCD 47LM5850 Contrast/Picture very white

looks like bad gamma ref voltages on the t-con. Pictures of the t-con board?.

+1

[tech2014]

Re: LG LCD 47LM5850 Contrast/Picture very white

Hi guys. I replaced the TCON board and no change, screen is still the same.

What else could cause this? A bad LVDS or main board? A bad panel??

[budm]

Re: LG LCD 47LM5850 Contrast/Picture very white

Check the GAMMA DCV on the GAMMA Voltage test points of the old board and the new board.

[tech2014]

Re: LG LCD 47LM5850 Contrast/Picture very white

ok how do I go about this. I don't see anything on the TCON that says gamma.

[budm]

Re: LG LCD 47LM5850 Contrast/Picture very white

ok how do I go about this. I don't see anything on the TCON that says gamma.

That is why I asked for the pictures of the T-CON board on post #2 to check the Voltages.
'Looks like bad GAMMA ref Voltages on the T-CON. Pictures of the T-CON BOARD?.'

[tech2014]

Re: LG LCD 47LM5850 Contrast/Picture very white

Sorry budm, I was having issues with my computer yesterday. Here are the pics of the TCON.

[tech2014]

Re: LG LCD 47LM5850 Contrast/Picture very white

Can anyone offer some guidance on this tv? Could it be a main board issue or panel?

[budm]

Re: LG LCD 47LM5850 Contrast/Picture very white

Too bad, there are no known test points for the Gamma ref Voltages.

[tech2014]

Re: LG LCD 47LM5850 Contrast/Picture very white

Hi guys. I replaced the TCON and Main board in this TV and the screen is still the same. What are the chances of it being the LVDS cable from the main board to the TCON?

Is there a way to rule out the LVDS?
See pic below. There are a lot of vertical lines on the screen. Sorry about screen, customer brought it in this way.

[ReeceyBurger123]

Re: LG LCD 47LM5850 Contrast/Picture very white

Why did you replace mainboard ? Check the tab bonds see if they are intermittent.