Hi all,
This is my first post in the forum, although I've been following Dave's videos for more than 6 months now
I've recently obtained some used Lenovo's laptops that have some board issues to and I'm trying to repair them, but this time I'm writing you about the LCD in one of them.
This T420 has a LTN140KT03-403 is a Samsung LED display, and I'm trying to find any useful information on it but didn't have any luck (no schematic, general description of how it works, datasheets for the ICs, nothing)
The good news is that I have a spare backlight (from a T430) and have narrowed down the issue to the circuit in the LCD, and given that I can see the image (barely) I believe that something must be going on with the IC that handles the PWM.
The ICs that I can see on the board are:
IC1: HV-EL L23 It's a 16-pin QFN (closest to the connector that goes to the backlight and closest to the big caps and inductors, I suspect handles the backlight)
IC2: LA64H-Q LAU5211XOB-E1 (no idea) --> It's a 56-pin QFN (closest to the connector that goes to the laptop: is it the driver for the LCD diodes?)
IC5: SiW SW5203 G2316900 1252 --> It's a 48-pin QFN (no idea)
I'll be starting my diagnose on the smaller one, the IC1, do you have any ideas/datasheet or schematic that you can share?
Big thanks, Martin.-