Question Weird Screen Artifacts...

[Goodie175]

So I finished my N64 portable a while ago and noticed it had strange lines in the bottom left of the screen... I thought maybe it needed the low pass video filter redone as I am using composite out. So I added a 75ohm resistor and the 47pf capacitor from the trimmed off part of the motherboard as diagramed on the N64 trimming guide. It didn't do anything to fix my issue. It did make the signal less washed out which was a plus. Anyway I though we'll maybe I had pressed the screen into place too hard when I was building the unit and hurt the screen. So after arrival of a new screen I soldered it in place of the current screen aaaaand... No change... the lines were still there. They also stay in the same location on the video even if I switch between 16:9 and 4:3 so I'm pretty certain it is related to the actual video signal. I am pulling my composite signal from U5 pin 12 the adding in the amp after that wiring the 75ohm resistor inline with the video and then running the capacitor in parallel between the video and ground after said resistor. I am also using a shielded wire for my video signal. If anyone has any advice I'd greatly appreciate it!

Best photo I could get of said issue:

 

[Stitches]

So I finished my N64 portable a while ago and noticed it had strange lines in the bottom left of the screen... I thought maybe it needed the low pass video filter redone as I am using composite out. So I added a 75ohm resistor and the 47pf capacitor from the trimmed off part of the motherboard as diagramed on the N64 trimming guide. It didn't do anything to fix my issue. It did make the signal less washed out which was a plus. Anyway I though we'll maybe I had pressed the screen into place too hard when I was building the unit and hurt the screen. So after arrival of a new screen I soldered it in place of the current screen aaaaand... No change... the lines were still there. They also stay in the same location on the video even if I switch between 16:9 and 4:3 so I'm pretty certain it is related to the actual video signal. I am pulling my composite signal from U5 pin 12 the adding in the amp after that wiring the 75ohm resistor inline with the video and then running the capacitor in parallel between the video and ground after said resistor. I am also using a shielded wire for my video signal. If anyone has any advice I'd greatly appreciate it!

Best photo I could get of said issue:
View attachment 27645

Does this happen on multiple displays? Have you tried feeding composite from a different device to that screen? It could be the screen board shitting the bed

 

[Goodie175]

Does this happen on multiple displays? Have you tried feeding composite from a different device to that screen? It could be the screen board shitting the bed

Yes I've tried it on multiple versions of the same screen, same issue. I'm going to try and hook it up to a TV tonight after work to see if it is the screens that are doing it or if it is the N64 itself generating the noise.

 

[Goodie175]

Update on this issue.

So apparently it is the screens. I have purchased a 2nd n64 and these screens DO NOT like its composite output. My first motherboard is a revision CPU 04 and the second a CPU 08 so it's not motherboard revisions causing the issues. I hooked up a ps2 to the screen and it did not do have the artifacting. Is it possible that I could add another video filter to stop these problems or is it a NTSC type that it doesn't like? I know there are different sub types of video signals like NTSC-M and NTSC-J would this possibly cause a weird interference if the screen didn't like it? I'm out of ideas... I would really like to use the screens as I already modified a 3d print to fit them.

Solution: Use the Ashida screen. It's driver board is better than the crappy amt630a that drives the cheap amazon screens I was using plus it's just an all around better screen for the extra $10 it costs plus it's the exact same size Just wanted to actually put a solution on here for anyone have issues in the future with this