Samsung S24E650XW Monitor Repair

Summary

Panel Type: LTM240CL04

https://www.displayspecifications.com/en/model/d74be05

24 in, PLS, W-LED, 1920 x 1200 pixels
Dimensions: 554.8 x 359.4 x 55.1 mm
Weight : 4.11 kg

https://www.panelook.com/LTM240CL04_Samsung_24.0_LCM_overview_21284.html

Interface type: LVDS (2 ch, 8-bit) , 30 pins Connector
Power supply: 5.0V (Typ.)

Problem Presentation

wrong mapping in the red channel of every other column leading to non-monotonous red values and black being a dull red. Occasionally clock glitches and noise.

Both effects are susceptible to slapping and bending of the enclosure.

Teardown

The rear cover is all clips, no screws. The VESA mount is attached to the plastic only.

The power supply / mainboard compartment is merely taped down onto the rear.

After removal of all the cables going into the shielded enclosure and unplugging of the LVDS flex cable, the shielded enclosure can be lifted off.

The cable assembly is labeled BN96-26694L. The cable can potentially be pulled out of the housing, and this flex cable connector style is not uncommon, althrough at the time of writing, the part or model name is not known.

Mainboard and Cable Breakage

With three screws removed and the power cable unplugged, the mainboard can be lifted out:

Note the black tape is on the contact side at the panel connector but the mainboard FPC header is bottom-contact, so here the contacts are on the opposite side of the black tape.

This makes the "AWM 20861" 1.0mm pitch, 30P flex cable an opposite-side contact type. Some panels use the same pin count and pitch cable with same-side contacts.

When rubbing the mainboard-side end of the flat flex cable with a cotton swab to remove possible contaminants, cracked traces were noticed:

This is strange because the flex cable has a stiffener and the bend radius is around 3 mm. However, the sharp corner lines up exactly with the main PCB edge and there is a visible crease in the flex cable substrate, leading to suspect that during assembly of the otherwise zero insertion force FPC, the cable was pushed into the PCB, initiating this failure.

Other than that, the cable should have some slack and is not necessarily bent back and forth repeatedly during transport or normal use.

Replacement Candidate

A Thomson brand TV type 32HC3106X1 cable was sold on ebay which appears to have a compatible connector and opposite-side 30P 1.0mm pitch FPC:

Panel-side connector up close:

As per a manufacturer website we're looking at FI-X30H / FI-X30HL:

which however might be the crimp-type connector. The [JAE datasheet])(https://docs.rs-online.com/b9cb/0900766b80fc1567.pdf) mentions FI-X30M which looks to be exactly the part and kind of assembly, also hinting at how to possibly disassemble the shell and swap the flex cable:

Repair

Old vs. new cables side by side. Didn't push my luck too far with the sharp bends and un-bending the previous crease.

A "restoration project" that was well worth it.