I have a few old laptops with good LCD panels that I wish to salvage and use as external VGA screen on other computers.
I'am no expert in electronics but I work with computers and know the basics of it. I also did a lot of research on the subject and did my best with no success. I invested some money on parts and really want to finish it but I can't do it without help.
So the LCD panel uses a LVDS interface to connect to the LCD controller board (MT-561B very similar to MT-6820-B).
This is the LCD board. I have some doubts on the red connector (1), the pin layout is printed in the board. I only connected the first ground and the first VCC input, leaving the others not connected. ADJ stands for the brightness adjustments, I'm guessing this is an output to the inverter to reduce the backlight brightness but I'm not sure. I don't really know what BL is but I have read somewhere that is like an on/off pin so I connected it to the 5V.
There is a jumper to choose 5V or 3.3V (4). I'am pretty sure I should use 5v but tried both with no success.
I think I got the LVDS interface cable right because in the pin layout the VCC pins match the red wires in the cable. The keyboard is connected in place as well. (3)
Another thing that I am not 100% sure is the pin mapping for the resolution (2). I want to use 1024x768 (8-1 or 6-1) to test it out, it's not the native resolution but It must be supported right?
There was no pin layout for the original LCD inverter so I bought another one, I can't really tell the specifications (can't access Aliexpress) but I'am sure it supports 12V input. Again I just connected the first VCC and GND pins, ADJ was connected to the LCD board and N/F I found out it means like No Function and should be connected to GND.
Everything is wired up (and not working) as the following layout:
I have an ATX power supply from a desktop PC and I use it to get the 12V and 5V that I think I need to use.
My results so far:
When I turn the power on the LCD panel backlight lights up just a bit, goes off and the keyboard LED keeps on flashing.
If I connect two LCD panels to the LCD inverter both backlights stay on, the keyboard LED flashes too.
This makes me believe that the backlights and inverter are working.
I'm sorry for the long question but I did everything I could and tried to explain it in the best way, now I'm out of moves. What do you think is wrong with the project and what should do next to try to fix it?
Thanks in advance
(I might have connected the 12V on the LCD controller which should get 5V)
The characters on the VGA chip are very small, I could not get a picture and maybe some could be wrong:
Himax Hx6856-A 080LAG 538DNTCC 955710 XM27345