ln32a300 dark picture

[ajshoe]

Have a samsung LN32a300 with a dark smeared over tinted picture, don't believe its backlit related. Anybody seen this on a LCD set or have any ideas ??

[budm]

Re: ln32a300 dark picture

That is bad GAMMA Voltage reference issue on the T-CON board, more likely the GAMMA IC P/N AS15 or AS19.
Please up load the good clear pictures of the T-CON board, there should be GAMMA Voltage test points on that T-CON board.

[diif]

Re: ln32a300 dark picture

I'd suspect a gamma issue. Can you take a good photo of the tcon board ?

[ajshoe]

Re: ln32a300 dark picture

pics - not easy getting to TCON bd

[budm]

Re: ln32a300 dark picture

https://www.badcaps.net/forum/attach...5&d=1522204903
IC on the bottom left, what is the P/N as printed on top, AS15?

[ajshoe]

Re: ln32a300 dark picture

magnified pic of chip

[budm]

Re: ln32a300 dark picture

AS15-G, that is common failure on T-CON board, there are many many threads about this IC.

[ajshoe]

Re: ln32a300 dark picture

just replace it ?? is there an upgrade for this chip ??

[budm]

Re: ln32a300 dark picture

You can verify the VGMA Voltages first if you want, I cannot see the test points in your pictures.
Ah, your pictures came back up!
https://www.badcaps.net/forum/attach...1&d=1522205818
I see GM1 ~ GM14 for the GAMMA Voltage test points.

[ajshoe]

Re: ln32a300 dark picture

first pics were blurry - take voltages tomorrow. ordered RM5101 bedtime

[ajshoe]

Re: ln32a300 dark picture

TCON voltages with no video input are
GM1 = 13.05
GM2 = 10.43
GM3 = 9.69
GM4 = 9.05
GM5 = 8.6
GM6 = 7.49
GM7 = 7.1
GM8 = 6.66
GM9 = 6.21
GM10 = 5.05
GM11 = 4.7
GM12 = 5.06
GM13 = 3.03
GM14 = 5.2

Vref = 13.3, VCM = 5.88, VDA = 13.74, SDA = 3.3

[budm]

Re: ln32a300 dark picture

Bad #12 and #14. See the pattern?

[ajshoe]

Re: ln32a300 dark picture

bought new board on Ebay - $20. picture is perfect. not real easy getting to TCON board. sets been working for 24 hours. thanks to all for the help.

[budm]

Re: ln32a300 dark picture

Thanks for the follow-up.