samsung le37s86bd possible t-con.

[senndogg]

hi. i have this 37 inch lcd tv which works well for a couple of minutes and then the picture is distorted in the horizontal 1/3 upper section.

the panel is Chungwa and the tcon a CPT370WA03C model.

i didnt find any useful info all over the web to troubleshoot this.

in a page where they sold this tcon i noticed that buyers had also bought a 48pin chip found in this t-con. it is a AS19-HG, a 18+1 Channel Voltage Buffers for TFT LCD.

ebay: t-con 45$ shipping included.
anyway thinking of experimenting with the buffers. 14$.

what do you think. could this chip be the defect of this tv?

i can post pictures of the t-con if you want.
thank you.

[tom66]

Ugh, Samsung using Chungwha. Crap!

It does look like a T-con issue. The fact that it's time based could mean a bad BGA solder joint - try pressing on the main processor and RAM. Also, reseat all connectors.

An LCD TV does not have replaceable buffers. There are driver ICs on the panel but if they go wrong the panel is scrap. Tab bonds probably couldn't cause this.

[senndogg]

this one looks ancient and cheapo. it doesnt have any BGA solder joints as you can see.
i am wondering now what is the eeprom exactly used for.

[senndogg]

anyone ever tried swapping an IC like this?

[tom66]

Originally Posted by senndogg

anyone ever tried swapping an IC like this?

I think they aren't available easily and it's a lot of hassle. Maybe a different screen size would work? I had a 40" Samsung that worked with a T-con from a 46" for the same model.

[senndogg]

i did some search and this type is size specific. there are several versions of this board, i have the 4G and there are 4C2, AB etc. which have different board layout but i think they should do the job. maybe this is just a revision code.
i asked if the 14$ AS19-HG could be replaced, because if that was faulty, i'd have a 100% reconditioned board, instead of putting an used one, with no warranty.

[tom66]

Originally Posted by senndogg

i did some search and this type is size specific. there are several versions of this board, i have the 4G and there are 4C2, AB etc. which have different board layout but i think they should do the job. maybe this is just a revision code.
i asked if the 14$ AS19-HG could be replaced, because if that was faulty, i'd have a 100% reconditioned board, instead of putting an used one, with no warranty.

On mine, there was a slightly different model code, but I took a chance and it worked.

What is the AS19-HG? Is it the processor? If so, and if you can find it cheap -sure, it might be possible. You'd need a hot air station and a good, steady hand, but not impossible.

[senndogg]

i am reviving this thread because i have been pre-paid to repair this tv.
the 2 hot topics:
1. is this a t-con problem?
i have posted more pics showing distortions in the screen during the movie and in menus too.
2. i have found several t-cons in ebay but none (excpet only one) matches the exact board revision. the part number is ok. the chunghwa panel part number too.
i studied a bit and there seem to be 4 mayor revisions of this board: 4C, 4C2, 4C21 and 4G. all have different board layout. components are mounted in different places in the board and the main chip differs too. vtii8874 in my t-con and vtii8872 in the 4C ones. i could go for the exact one the 4G but it is a couple of dollars more expensive and i dont see the point in replacing with a part which revision is known as notorious. i'd prefer the older one if they are more reliable and of course if they work... i am little desperate... will they work?

[senndogg]

time for some feedback:

the t-con arrived!
it was the 4C21 revision. the LVDS cable was not a straight fit. i had to chop the locks because the lvds cable would not go. anyway. picture was ok. my desktop looked ok there. no more distortions.
BUT, the refresh rate, which i forgot to mention in past posts, was STILL very low, 4-5fps maybe. watching a movie was like watching a slide show. totally not happy with that! and to worsen things, the 1/3 upper section began old problems! devastation! waited 2 weeks and no real world results!

googling around brought me nightmares, worst scenario, main board gone. reccaped, no difference.

took a break, some coffee and decided to go deeper.
dismantled the panel, and guess what, the culprit, the death, the mother of every evil, a bad tab bond. (photo)
applied a non-conductive-very-thick-piece-of-solid-thermal-tissue and forced the mounting frame over it keeping it firmly pressed. or i hope so.

conclusion:
excellent picture (this thanking the new t-con), and the strange thing, it ran flawless. no more low frame rate!! yes!! a bad tab bond can cause low frame till freezing picture!
the 37" samsung is a successful closed case!

cheer guys! hope i was helpful!