Samsung LCD LN40AQ550P3FXZA Solarization Issue

[jm442123]

Hi all. Any help would be greatly appreciated.

Thiss is a Samsung LCD TV model LN40A550P3FXZA with a picture solarization issue that I am trying to trouble shoot.

I have spent most of my time troubleshooting the T-con board. All test points on the T-con board have stable DC voltages. I have documented those voltages on all test points but can not find anywhere what these voltages should be. The GRD test point on the T-conn board reads 1.8v DC which seems like it should read 0 v DC.

No capacitors on any of the boards appear to have issues. I would like to be sure which board needs to be replaced before I buy a replacement board. Attached are pictures of the TV picture that shows the issue if that would help isolate which board may be bad.

Thanks

Jim

[jm442123]

Re: Samsung LCD LN40AQ550P3FXZA Solarization Issue

Also attached are pictures of each of the 3 boards on this Samsung LCD LN40AQ550P3FXZA with a Solarization Issue.

[nomoresonys]

Re: Samsung LCD LN40AQ550P3FXZA Solarization Issue

See where it says GAMMA? those would be the points to test.

[nomoresonys]

Re: Samsung LCD LN40AQ550P3FXZA Solarization Issue

they should go gradually in one direction like 1.2, 2.3, 3.4 so on if next one is like 1.2 then you have a problem with the gamma ic, I do believe.

[jm442123]

Re: Samsung LCD LN40AQ550P3FXZA Solarization Issue

Yes. I have tested the GAMA test points and have the readings for each test point, but I don't know what readings would indicate proper voltages. I have also tested the 5 additional test points inside the GAMA test points and the 5 test points to the left of the yellow ribbon connector. However I have no documentation that tells me what each test point should read.

[nomoresonys]

Re: Samsung LCD LN40AQ550P3FXZA Solarization Issue

What are your readings? start with 1 then 2, 3, thru 17 post results here.

[jm442123]

Re: Samsung LCD LN40AQ550P3FXZA Solarization Issue

These are the reading from ground to the test point, not reading between test points. Meaning black to ground and red to test point 1, etc.

1 15.0
2 12.83
3 12.04
4 11.14
5 10.73
6 10.40
7 9.98
8 9.12
9 8.16

10 13.19
11 14.08
12 11.64
13 6.81
14 5.62
15 4.88
16 3.56
17 2.65

[diif]

Re: Samsung LCD LN40AQ550P3FXZA Solarization Issue

Yes, faulty gamma ic, I'd guess an AS15.

[R_J]

Re: Samsung LCD LN40AQ550P3FXZA Solarization Issue

Looks like AS19-H1G

[neilc6]

Re: Samsung LCD LN40AQ550P3FXZA Solarization Issue

Your tcon part number is 35-D026047. Lots on ebay. I have gotten damaged and non-working used tcons on ebay so it's a bit of a crap shoot unless you can find a new one. I find 10 yr old obsolete LCD TVs are getting less worth it to repair. TV is only worth about $80 working.

[diif]

Re: Samsung LCD LN40AQ550P3FXZA Solarization Issue

Looks like AS19-H1G

You're right, I didn't zoom in on the photo.

[jm442123]

Re: Samsung LCD LN40AQ550P3FXZA Solarization Issue

Thanks for the opinion that it is a bad T-Con board because of the bad Gama IC, but what leads you to that conclusion based on the test point data? Just curious.

[diif]

Re: Samsung LCD LN40AQ550P3FXZA Solarization Issue

Thanks for the opinion that it is a bad T-Con board because of the bad Gama IC, but what leads you to that conclusion based on the test point data? Just curious.

A non faulty one produces a linear graph when plotted.

[nomoresonys]

Re: Samsung LCD LN40AQ550P3FXZA Solarization Issue

.

[nomoresonys]

Re: Samsung LCD LN40AQ550P3FXZA Solarization Issue

.

[jm442123]

Re: Samsung LCD LN40AQ550P3FXZA Solarization Issue

Yes. I ordered a "new" T-con board on ebay for $28.22. It looked like the Gama IC was about $12. At those prices I would just a well go with a whole new T-con board. I am hoping it is a good T-con board.

Diff .... So a good board would have a downward slope of the voltages from TP1 to TP17. Is that correct? Thanks for all of your help.

Jim

[R_J]

Re: Samsung LCD LN40AQ550P3FXZA Solarization Issue

This is a rough graph of you voltages, its not that bad but your picture is not that bad. If more of the voltages were off your picture would look a lot worse.

[budm]

Re: Samsung LCD LN40AQ550P3FXZA Solarization Issue

T-CON check spreadsheet by Tom66:
https://www.badcaps.net/forum/showth...&highlight=VGH

[nomoresonys]

Re: Samsung LCD LN40AQ550P3FXZA Solarization Issue

Did you read post 4?? On your chart you're ok 1 thru 9 then it goes up, which is bad. Not rocket science.

[nomoresonys]

Re: Samsung LCD LN40AQ550P3FXZA Solarization Issue

lin·e·ar
/ˈlinēər/
Learn to pronounce
adjective
adjective: linear

1.
arranged in or extending along a straight or nearly straight line.
"linear movement"
consisting of or predominantly formed using lines or outlines.
"simple linear designs"
involving one dimension only.
"linear elasticity"
Mathematics
able to be represented by a straight line on a graph; involving or exhibiting directly proportional change in two related quantities.
"linear functions"
2.
progressing from one stage to another in a single series of steps; sequential.
"a linear narrative"

Origin