Nanao messy image I don't know how to describe it

[man1aco]

I don't even know how to describe this defect to search on google

NANAO MS8-26SU

 

[ShootTheCore]

Looks like a horizontal sync problem.

 

[Mrhide]

which game are you running? is that king of fighter 98 ?

are you on low (15 ) or high (24) resolution? this connector on the chassis allows you to select one or the other ( it should be on low if you are running KOF9

 

[BuddyC]

Have you tried adjusting the H. Hold pot on the chassis?
You can download the manual from the link below.

https://www.flippers.com/pdfs/Nanao_MS8-26SU.zip

 

[Mukuro_W]

If all is set correctly then most likely it is the sync ic

 

[man1aco]

All set corretc to LOW 15khz , I have some spare boards for parts , I can replace this sync PCB

 

[Mukuro_W]

Also the caps in that area should be replaced, along side with the ones in the vertical out area those chassis, are prone to fail there due to the heat and the weight of the two heatsinks.