Truxton PCB with disturbed output - could use some help

[waiwainl]

I received a Truxton PCB today
The gameplay and sounds are fine. But there is a disturbance on the signal . The background should be normal black.


I tried 3 different cabs, same effect. The board looks quite clean


I cleaned the JAMMA edge, but not much dirt came off - it was already clean.
On closer inspection of the board I can only see some 'dirt' here (click for bigger picture):


Any suggestions? Would it help if I clean the above area? And how would I do that? (I use alcohol for the JAMMA edge).
Thanks.

[waiwainl]

Updated 1st post with a picture of the whole screen.

[stockspyder]

Sorry if it's a dumb response as you seem to know what you're doing. But it's not just the brightness on the monitor? I know every board is a little different and some need adjustment on the monitor when you swap them in.

Is it a weird rainbow effect as shown in the one picture, or just a brightness issue?

I just got the first game for my machine I had to turn the 5v down on. For some reason my particular copy of a certain konami game needs the 5v at 4.88 to function properly otherwise it is washed out and staticky. Which is weird to me because I own over 20 pcbs and had never experienced that issue til now.

Best of luck

[waiwainl]

Thanks - it is not the brightness, on all cabs the same problem arrises. I also have Hellfire from Toaplan, which displays just fine with current settings (apart from the ever H & V adjusting )

Better picture:

The red should not be there, that should be black.

On advise I checked the ground with pin 14 (video) and all ground pins. They all are connected properly.

I tried voltage as well, went from 4.3 (sounds become weird) to 5v. But no difference in the image.
Something seems to be influencing the video output.

I tried to review all pins of all chips/caps/etc to see if any soldering or corrosion issues can be spotted (with my limited experience ) I at least could not see anything strange.