Samsung LE37B650T2PXXN nearly white picture

[Gulpman]

Hi everyone,
I'm completely new to TV repairs. While searching for the cause of the symptoms of my TV - having a nearly white picture whilst sound is fine - I stumbled upon this forum.

After seraching here and reading the related threads, I think my problem is related to the T-Con board.
I already ordered an "new" T-Con board via AliExpress, but the symptom is the same, after changing the T-Con board: still nearly white picture and sound is fine.
So either the cause for my issue is not the T-Con board or the "brand new" T-Con wasn't brand new. As I could see some remains of Fluxx on the board, I guess it wasn't.

Anyway - I'd like to fix the TV and therefore would appreciate it if someone could guide me in the right direction. I do have some experience in soldering SMD, so if the problem can be isolated to some chips / caps / whatever, I'm positive that I am able to exchange the parts.

Attached you can see a video with the symptoms (had to zip it) as well as pictures of my original T-Con board (the chinese exchange is in the TV right now - but type number was identical to my T-Con board).

So for my questions:

1. Is this symptom related to the T-Con board?
2. If so - in most cases where someone helped, first thing was to measure the test points on the board. Which ones would that be? There are three places which could be tested (see pictures).
3. If not - what could be the cause for the nearly white picture?

Any help is higly appreciated.

Thank you very much in advance,
Sascha

[dick_barton]

Re: Samsung LE37B650T2PXXN nearly white picture

If you could measure the voltages on the Tcon perhaps someone could offer you further advice.
There's VG1 through to VG22
VGH, VGL, V1D2, V3D3, HAVDD, AVDD, TP_B2D5V and several others points that could be measured and prove helpful.

[dakarpesca]

Re: Samsung LE37B650T2PXXN nearly white picture

it seem be as15 chip the culprit you have to change it

[zomi]

Re: Samsung LE37B650T2PXXN nearly white picture

+1 Change the as15 chip
If there is an as15 chip and u have this issue just change the chip.

[yoritomo]

Re: Samsung LE37B650T2PXXN nearly white picture

Yes it is a common problem with this chip, the only easy and cheap way to replace it is by regulated hot air gun with flux, I bought a very cheap one following the review of Dave Jones about 50 € on Ebay and, 2 years already i am using it, it is clearly not a pro tool but no problems until now, and spare heating elements are available too.

Edit: hum i did not watch correctly the image, now i see it has reverse writings, surely a second problem not relative to AS15F. First time i see reverse image anyway.

[ReeceyBurger123]

Re: Samsung LE37B650T2PXXN nearly white picture

+1 AS15 Gamma Ic failure again.

[Gulpman]

Re: Samsung LE37B650T2PXXN nearly white picture

Thanks to everyone who replied to this thread so far!

To summarize it:

• Cause seems to be a faulty AS15 chip (here: AS15-HF)
• To be really sure, I should measure test points VG1 - VG22 (and for further helpful info VGH, VGL, V1D2, V3D3, HAVDD, AVDD, TP_B2D5V

So I ordered a few AS15-HFs, as it takes a while till they will be here after ordering and they nearly cost nothing.
Will do the measuring this evening and post the voltage of each of the Vxx pads.

Again: Thanks so much for helping guys!
-Sascha

[Gulpman]

Re: Samsung LE37B650T2PXXN nearly white picture

[...]
Edit: hum i did not watch correctly the image, now i see it has reverse writings, surely a second problem not relative to AS15F. First time i see reverse image anyway.

No, the picture on my TV screen is not upside down - could be that I had my phone turned upside down and auto orientation within the picture was faulty. So you see it upside down in the image, but on my TV only the nearly white screen is an issue - the text is as expected.

[Gulpman]

Re: Samsung LE37B650T2PXXN nearly white picture

If you could measure the voltages on the Tcon perhaps someone could offer you further advice.
There's VG1 through to VG22
VGH, VGL, V1D2, V3D3, HAVDD, AVDD, TP_B2D5V and several others points that could be measured and prove helpful.

Here we go with the voltages of the two T-Con boards I have.

Original T-Con board from TV:
VG1=15,51
VG2=15,46
VG4=13,02
VG6=11,17
VG8=10,39
VG10=7,83
VG11=7,77
VG12=7,06
VG13=7,00
VG15=5,160
VG17=4,093
VG19=2,475
VG21=0,345
VG22=0,300
VGH=31,51
VGL=5,969
V1D2=1,201
V3D3=3,315
HAVDD=6,97
AVDD=16,00
TP_B2D5V=2,499

2nd T-Con board from AliExpress:
VG1=15,46
VG2=15,07
VG4=12,52
VG6=11,04
VG8=10,13
VG10=9,30
VG11=8,29
VG12=7,57
VG13=6.54
VG15=5,71
VG17=4,78
VG19=3,28
VG21=0,687
VG22=0,297
VGH=31,03
VGL=5,970
V1D2=1,196
V3D3=3,307
HAVDD=7,35
AVDD=15,96
TP_B2D5V=2,500


Best,
Sascha

[dick_barton]

Re: Samsung LE37B650T2PXXN nearly white picture

I was hoping to put the data you supplied into Tom's spreadsheet but it doesn't seem to like the empty cells ie VG3, VG5 etc.
However looking at the results it does look like a bad Tcon but I doubt if two of them are faulty and they both appear to have almost identical readings. Is VGL positive or negative since the spreadsheet indicates it should be negative?

https://www.badcaps.net/forum/showth...ma+spreadsheet


I now wonder if the main video processor is faulty on the main board.

If anyone else can offer help here it would be appreciated.

[Diah]

Re: Samsung LE37B650T2PXXN nearly white picture

did you tested call menu screen if it show also white or normal color??

[victor_cj]

Re: Samsung LE37B650T2PXXN nearly white picture

[*]Cause seems to be a faulty AS15 chip (here: AS15-HF)

AS15-HF U0103 faulty


or AS04-F/AS34-G U1 faulty

[Diah]

Re: Samsung LE37B650T2PXXN nearly white picture

AS15-HF U0103 faulty or AS04-F/AS34-G U1 faulty

are there any post from owner talking on Menu had same issue ??

i just wounder how do you know they are fault with out Menu ´Screen test if it same issue or not ?? LOL T-CON never being Voltage measure unless F of it and some in out feed back V. other all signal depending on bits. streaming signal are higher bits, menu screen are low bits.

hope all of you correct T-CON issue

[budm]

Re: Samsung LE37B650T2PXXN nearly white picture

BTW, what do you get on the screen if you have one ribbon cable between the LCD panel and the T-CON connected one at a time?