[Solved] Grundig 42 VLC6121 C: TCON LC420WUN-SCA1 Issues, Damaged AS15AF, Image Disturbances & Fixes

Hello. The symptom is like a damaged AS15AF which is not present in the LC420WUN-SCA1. Damage as in the picture

but he could also attach with green artifacts / pixelosis or completely black with occasional fragments of a fragmented image. evidently damaged TCON because when pressed down, a normal image could appear. After soldering the main IC and the LVDS connector, a normal image appeared, but after a while the symptoms returned but less intense (the image is less disturbed). Gently pressing down on the TCPN plate returns the image to normal. Of course, I intend to re-sell TCON, maybe even more widely. I am even considering removing the Pb free tin and replacing it with leaded. Now, however, I am asking if it will not be a damaged LG chip and heating it during soldering did not improve it a bit? I soldered with a tip on a gel flux (for BGA). I am asking because TCON is available.

Such T-con on a pcb board: (6870C-0310C) then e.g. 6871L-2045A
- for matrices: LC420WUN-SCB1, LC420WUE-SCA1, LC420WUE-SCA2, LC420WUE-SCV1



Look carefully, there the Gamma correction is done on the circuit. Link

But a lack of LSB can also produce similar symptoms. As I mentioned, pressing the TCON resulted in the disappearance of the symptoms (and these were either the same as in the picture or the lack of the image or its parts), which could suggest the lack of a few bits and not necessarily the least significant ones .... And under the microspop you could actually see some imperfections of the solders. The re-soldering of the chip gave measurable results in the form of a good image which broke down after warming up the module, but it was better than the first one and it did not disappear anymore. With a damaged AS, I did not meet the fault with the pressure. Although on the other hand I have never researched it and always mentioned Ace right away ...

And any measurements, apart from ... the clamp, did you take?

You will see what and how?

This is the datasheet below of this matrix


________________
6870C-0310C / 6871L-2045A
e.g. 42LK450> matrix: L LC420WUN-SCA1
-IC LG5803A, MAX17113ETL, TPS65192, MAX9668ETP, 432RP, RT8250


LG5803A controller
- LG5803A = TL2428MC
- type in google: TL2428MC filetype: pdf ... and read



OPT_N allows you to rotate H (written with levels: "H" Normal Display / "L" Rotation Display),
* H_CONV allows for: Lo (H 1dot Inversion) - no changes, Hi (H 2dot Inversion) - image divided by V, evenly (left - right half of the image, right - left ...)

The rest on Link

I think, in fact, I'm sure the problem is here ...


Added after 48 [minutes]:

And this is a secondary problem, most likely due to flux residues (although I washed with isopropyl) in the LVDS socket, which caused a partial dissolution of the LVDS tape under pressure and temperature. Or maybe I folded it up too quickly without waiting for the isopropyl to dry and it was he who dissolved the tape. The fact is that after tweaking the soldering a few minutes worked.For now I have cleaned it in nitro and wait for it to dry ...

It works after cleaning.