Jailbars on a front loader - help required

Hi guys,

I’m trying to get an old French NES to work

I’m having those strange vertical interference, particularly visible on the blacks.



At first I thought there was something wrong with the av out module so I’ve replaced it entirely with the same result

I then changed all the electrolytic capacitor on the main board... same

Then replace the cartridge connector... same.

Then replaced Q1... same

Any idea ?

 

Probably no help, but I have this exact same artifact on both of my Wii systems against dark colors, though the lines aren't as thick