Samsung LN46A630 white screen issue

[shapman]

Hi all ... new to this board and hoping for some assistance. I searched other postings but couldn't find the exact match for my issue. My thought was maybe the T-Con LCD board but wasn't sure if I could test to be certain.

When turning on the TV the screen would be all white (not polarized). After maybe an hour leaving the TV on, I could turn off and back on and the picture would be fine. Occasionally it would start white and fade to clear picture. Progressively it would get worse and could be on all day before the picture would come back after turning on and off. Now the screen is all white and the picture does not come back. I can't see anything on the screen. The audio works fine. Any thoughts would be appreciated.

[budm]

Re: Samsung LN46A630 white screen issue

At least up load the pictures of the T-CON board.

[shapman]

Re: Samsung LN46A630 white screen issue

Thanks, here is a picture of the board.

[dick_barton]

Re: Samsung LN46A630 white screen issue

You could try heating the Tcon with a hair dryer and see if you can get the picture back. If you can by heating then you do have a Tcon problem.

[budm]

Re: Samsung LN46A630 white screen issue

https://www.badcaps.net/forum/attach...1&d=1469542125
Please remove the square pink thermal transfer pad from the IC on the top left to see what the P/N is. It is the GAMMA IC, probably AS15/19 chip.
Also get the screen shot of you see on the screen when it is bad.
You can also take the GAMMA Voltages reading and also see how hot the GAMMA IC gets.

[shapman]

Re: Samsung LN46A630 white screen issue

I'm not certain I removed the thermal pad correctly as I do not see any numbering on the chip. Picture attached. I also included the picture of the screen issue when turned on. The lines only show in my cell phone picture.
Also is there any instruction how to take the Gamma readings on this board?
I searched but didn't find any.
Thanks

[budm]

Re: Samsung LN46A630 white screen issue

You can use Alcohol to clean the top of the IC to see the marking on top of the IC.
Do you see the exposed copper pad with white circle and it has VCOM printed next to it? Then to the left of that VCOM pad, you can see 12 exposed pads in the row, those are the VGAMA 1~12.
You will use your dcv meter to check the DCV on each one of those pads and report what you get, You will do that when the TV is on.
I.E.
VGAMA 1 = XX V.
VGAMA 2 = XX V.

[shapman]

Re: Samsung LN46A630 white screen issue

Hi these are the readings I got;

VGAMA 1 = 15.2 V
VGAMA 2 = 13.1 V
VGAMA 3 = 11.04 V
VGAMA 4 = 10.31 V
VGAMA 5 = 9.9 V
VGAMA 6 = 8.08 V
VGAMA 7 = 7.06 V
VGAMA 8 = 5.1 V
VGAMA 9 = 4.66 V
VGAMA 10 = 3.88 V
VGAMA 11 = 2.22 V
VGAMA 12 = .35 V

[shapman]

Re: Samsung LN46A630 white screen issue

One thing I would add about the readings is that the values were very inconsistent until left on for about 10 minutes ... I'm not sure if that is normal or not?

[budm]

Re: Samsung LN46A630 white screen issue

VGAMA 12 does not look right at all, I have never seen the reading close to 0V (<1V).
Does the IC get too hot to touch with your finger?

[kevinm34232]

Re: Samsung LN46A630 white screen issue

This is common issue with that T-Con, it's the AS15-G IC.

http://www.ebay.com/itm/131591524603