Atari Lynx 2 display issue

I have an Atari Lynx 2 that has what it appears to be a display issue.
Another example.

Since I had another identical unit that I was able to successfully repair, I decided to swap the display, once I did that I noticed that the issue follow the motherboard, to be sure I tested them both so I know both displays are OK and I am using the same AC adapter BTW.

I used the same cart so I know it's not that, I checked the cart slot and all the pins are accounted for and in good shape, for good measurement I sprayed contact cleaner and tested it again with same results; then I cleaned the display connector as well and try re seating it a few times, but the issue persisted.

For good measurements I re solder the cart slot pins as well as the display connector pins, since that didn't seem to work I decided to re cap the unit, once I did that and test it again the issue still remains, same as before.
Any input would be appreciated!

 

McWill on AtariAge sells replacement screens that use the digital video signals coming from the console if you need them. I think it has an optional VGA output too. He has one for the Game Gear too.

 

VRAM? If it seems to be a motherboard-related problem that's the first thing that comes to mind. If it's SMD and you don't want to take it off you can try to piggyback it with known-good chips and/or cut bad chip's pins.

 

I would do that if I had a spare board for sure, but that is what I was thinking because the games are playable so it can't be the CPU or the RAM, the sound works OK as well.

 

One of the CPU drives the LCD directly. There are schematic on Atariage and console5 forum for Lynx 1, and I sent schematic for Lynx 2 to Console5. What I would try is check the trace between the CPU and the LCD pins. There are inverters and buffers on a few of the lines between CPU and LCD, check that too. And do check if the LCD is getting correct voltage, low voltage may cause glitchy display.