42LG50 Red Tint and Dim Screen

[tomcat5512]

I have a 42LG50-UA tv. When I turn the TV on, the image is good for about 30 seconds. The image then becomes increasingly saturated with red and slightly dim. Images look coarse and the problem is especially apparent in skin tones. I have a multi-meter but my experience with electronics is limited.

[sordids999]

Re: 42LG50 Red Tint and Dim Screen

can you supply a picture of the fault ?

[tom66]

Re: 42LG50 Red Tint and Dim Screen

And a picture of the T-con board will help (top of TV usually, connected to the main A/V board, which is in your 1st picture)

[tomcat5512]

Re: 42LG50 Red Tint and Dim Screen

I tried to capture the fault in the image with these pictures from the TV. The ones labeled correct were taken from my phone and the ones labeled fault were taken from the TV set. I also took a couple pictures of screen test images on my TV. The screen test pictures I found online and projected to my TV; they are not from the TV menu as I could not find any there. To my untrained eye, the test screen pictures looked good.

[tomcat5512]

Re: 42LG50 Red Tint and Dim Screen

I took these additional pictures of the TV set components.

[budm]

Re: 42LG50 Red Tint and Dim Screen

That looks like Gamma Voltages problem on the T-CON board, U7 is AS15??

[tomcat5512]

Re: 42LG50 Red Tint and Dim Screen

Thank you for the help budm. Is "U7 is AS15" a reference to a bad processor chip? Do you have a link to show the replacement of a T-CON board with similar connectors?

[budm]

Re: 42LG50 Red Tint and Dim Screen

AS15 is the GAMMA Voltage reference IC.
Your T-CON board P/N is 35-D023305 as printed on the bar code sticker.
http://www.shopjimmy.com/cmo-35-d023305-t-con-board.htm
Please verify the numbers since your pictures are not in focused.
You can also check the DCV of the Gamma Voltage test point #1~17 with reference to chassis GND.
http://assets.shopjimmy.com/media/ca...3305-top_1.jpg

[tomcat5512]

Re: 42LG50 Red Tint and Dim Screen

1-13.02V
2-11.68V
3-10.96V
4-9.96V
5-9.78V
6-9.50V
7-8.96V
8-7.55V
9-6.99V
10-6.40V
11-6.02V
12-5.04V
13-4.76V
14-5.23V Not a typo
15-3.96V
16-2.63V
17-1.70V

[newtothis]

Re: 42LG50 Red Tint and Dim Screen

14 Says yes the Gamma IC is bad.

Yes budm that is the correct part#

Replace T-con or if you are handy with a soldering iron or have a Hot Air station you can change the IC

[tomcat5512]

Re: 42LG50 Red Tint and Dim Screen

Thanks to everyone who helped. @newtothis I ordered a new board. My hand isn't steady enough for soldering.@tom66 I read another thread you started on a different forum about the AS15 and AS19 ICs going bad. I have the AS19-H1G IC. I don't know if these events are related but my house was hit by a power surge which destroyed a couple battery chargers I had plugged in. That was about the same time the problem in my TV started. The TV is 6 years old. @newtothis are there any tips for replacing the T-CON board? Again, this is the first TV I have ever attempted to repair. I did read the manuals posted by budm.

[newtothis]

Re: 42LG50 Red Tint and Dim Screen

Easy swap, Just careful with the ribbon cables

[tom66]

Re: 42LG50 Red Tint and Dim Screen

I think the failures just "happen", and there's little you can do to prevent it.