Hey, thanks fot he replies
yes, it's rgb modded. Weird thing is i have two of them (with custom cable), both have the same exact mod, first one no issues, the second one has this kind of problem.
I've been asked by a friend to change caps on boths as he's not able to solder, but thats where my skills pretty mutch ends. I know snes/nes/md stuff but i'm not realy into pce and i do not know if this could be a common problem, i was thinking infact that not-changed caps could be the main issue, i was sure about cause i fired up the console ones while changing them and i noticed different things like going to not display/no sound at all till here.
Unfortunatly i do not have many caps left in order to change all of them once for all, so i was thinking about an area on the board i might complitely change to fix this issue