Blue Screen of Frustration

[shaynestacy]

Hi Everyone,
Long time Neo Geo'er, first time poster. Nice to meet you all! I owned an AES back in the early 90s, then added and MVS to AES adapter in the late 00s, then got rid of it all about 10 years ago. My son is a big baseball fan and he loves Baseball Stars, so I grabbed a 4-slot cabinet from a warehouse clearout and it has been nothing but problems. The monitor flyback was bad, so I had that repaired and monitor tested good... but the monitor only displays dark blue and maybe red.
So, I thought I had a board issue. Bought a 2 slot board and same blue issue. I replaced the power supply since it was hacked (see pic)- still blue. I compared JAMMA pinout to Neo Geo pinout and even if this cab was rewired for JAMMA, the color outputs on the board are consistent between the 2 formats so I would think that is not the problem...
Has anyone seen this issue before? Can you hazard a guess as to what the issue could be? I don't have the time to rewire the cabinet, so I am hoping it is an easy fix.
I attached a photo of an example of the blueness, and one of the old power supply
Thanks!!!
Shayne

 

[max 330 mega]

Youll need to check the wiring of the jamma harness first, then if everything seems correct there it might be that the monitor either needs a cap kit or the green electron gun might be dead in the monitor itself.