PlayStation Development Network

Then one day.....
Hi everyone, today my ps1 starts to show some strange lines on screen. I have tried the same cable and the same screen with other ps1 and they haven't the same problem.
This ps1 has PSIO munted but it has been almost a years with no issue.
Thanks.

Looks like a trace (connection between chips) or a VRAM chip is going bad.
It's very hard to repair, even with tools.