Solarized Samsung LN37A450C1DXZA

[jbjsabu]

A free TV. It comes back on with a normal picture after being turned off, but becomes more and more solarized with time on.

I shot cold spray over most of the boards' parts with no effect.

I haven't measured any voltages anywhere yet. Three of the four big caps on the power board might be a little bulged on top.

The menu has normal colors.

I re-seated the cable between the main board and the t-con board - ng.

Any advise on how to proceed?

[budm]

Re: Solarized Samsung LN37A450C1DXZA

You need to get to the T-CON board which is under the metal shield sitting at the bottom center of the chassis.
Probably bad Gamma Vref IC.

[budm]

Re: Solarized Samsung LN37A450C1DXZA

BTW, the power supply board also has at least 3 bad caps with bulging tops, they are at top left of the board.
https://www.badcaps.net/forum/attach...6&d=1482888144

[ReeceyBurger123]

Re: Solarized Samsung LN37A450C1DXZA

Replace ALL THE BAD CAPS FIRST replace any Samwha Xc (light blue case) Wl and Wb series caps. Seems like corrupt Mb software to me could of been caused by the badcaps.

[jbjsabu]

Re: Solarized Samsung LN37A450C1DXZA

I have the caps on order.
Not to put the horse before the cart, but I don't find a replacement t-con board for sale anywhere, but shopjimmy has a chip that might be correct. What are the chances I can replace that chip with just a soldering iron if I need to go that route?

[budm]

Re: Solarized Samsung LN37A450C1DXZA

U202 is the GAMMA Vref IC, AS15?

[jbjsabu]

Re: Solarized Samsung LN37A450C1DXZA

U202 is the GAMMA Vref IC, AS15?

Yes. It says AS15-F.

[jbjsabu]

Re: Solarized Samsung LN37A450C1DXZA

I have replaced the four 1000uF electrolytics and two blue film caps on the power board.

Now I will connect everything back together and measure vgamma's ??

I only see 14 VGAM labeled, but no test points corresponding to them. Could they be under the ID sticker with (8?) more TP's?

Or, what should be next?

[diif]

Re: Solarized Samsung LN37A450C1DXZA

Its the points scattered about marked REF.
Or just replace the AS15 and forget the measuring.

[CapLeaker]

Re: Solarized Samsung LN37A450C1DXZA

replace that AS15. These fail a lot.

[johns1mj]

Re: Solarized Samsung LN37A450C1DXZA

Double check the menu. I have had some that are solarized but are hard to see. If the menu is not solarized but the picture is solarized I would be looking at the input board. A bad t-con should distort all pictures not some.

Someone please correct me if I am wrong.

[jbjsabu]

Re: Solarized Samsung LN37A450C1DXZA

Well, rather than jump in and replace the gamma chip (which I am actually looking forward to trying - besides which the replacement chip is a couple weeks away delivery from China) I measured the VREF's ON THE t-con board as follows:

REF 1 17.9
REF 2 17.3
REF 6 12.0
REF 7 11.2
REF 8 10.8
REF 10 9.0
REF 11 8.9
REF 12 8.0
REF 13 7.3
REF 15 5.5
REF 16 5.1
REF 17 4.4
REF 21 0.7
REF 22 0.4


Also on the t-con board is

VREF_12 14.0
VGMA_REF 18.1
VZ_REF 2.9

I downloaded the t-con spreadsheets to check the voltages ("GammaCheckGood.xls" and "GammaCheckv11.xls") to OpenOffice and the only thing that downloaded was a sample PASS and a sample FAIL results page - no place to enter values.

Anyway,seeing those numbers,I looked at the power board:

5.3V 5.9
12V 13.8
STBY 6.1

Screwy or not? Where am I at?
Thanks for any guidance.

[budm]

Re: Solarized Samsung LN37A450C1DXZA

https://www.badcaps.net/forum/attach...2&d=1483229135

Some one did really bad solder works on that AS15 IC, look at those pins on the top row!

[petehall347]

Re: Solarized Samsung LN37A450C1DXZA

only time i had this problem was bad panel . can be fixed by fiddly work apparently . cutting traces etc on the panel connections .
try a new tcon board first though to be sure .

[jbjsabu]

Re: Solarized Samsung LN37A450C1DXZA

https://www.badcaps.net/forum/attach...2&d=1483229135

Some one did really bad solder works on that AS15 IC, look at those pins on the top row!

Actually, that's sticky tape residue from the foam pad heat mover.

[budm]

Re: Solarized Samsung LN37A450C1DXZA

I do expect to bent pin like that, may camera angle? Need to find VGMA 2-5.

[jbjsabu]

Re: Solarized Samsung LN37A450C1DXZA

It does look askew,doesn't it? I will take a closer look tomorrow.

There is no test point for VREF 3, 4, 5 that I can find. Are there points on the
chip or a connector I can probe?

Do the other V's look reasonable?

[petehall347]

Re: Solarized Samsung LN37A450C1DXZA

get it cleaned up with iso and look again

[jbjsabu]

Re: Solarized Samsung LN37A450C1DXZA

A good scrub with IPA shows a good looking connx on the AS15.

I pull up the service menu with mute 1 8 2 pwr and the test pattern options don't seem to be available.

I wish I could pin down where this set's problem lies. It seems like there should be a better way than just swapping out chips and boards willy-nilly.

I guess I will wait for my replacement AS15 to come in and and see where it goes from there.

Thanks for the looks and consideration.

[petehall347]

Re: Solarized Samsung LN37A450C1DXZA

connections look real good now ..try heating it up with a hair drier ... had one a while back that only worked properly when warmed up solarize wasn't as bad as that though . ..also try freeze spray .