Sony BVM incompatibility with some boards

Green Beret

Fio's Quartermaster
I have a Sigma Raijin supergun connected on a 14" Sony BVM monitor 1416p model. I used to have heavy RGB bleeding and weak signal and dark image with M92 boards. 3x 75ohm pull down resistors on RGB lines (a resistor between each color and its ground) in the scart solved bleeding and made image look as normal, but introduced interferences like vertical lines. So I removed the 75 ohm resistors and then I discovered that my scart to bnc cable had no RGB grounds connected to the ground. Using a newer cable which I had already spare and those RGB grounds were connected into that one, solved the problem and now M92 boards don't have color bleeding and interferences are mostly gone, If not 100%, it is very difficult to spot vertical lines.

So to sum it up, It now works without the 75 ohm pull down resistors but with RGB grounds connected both in my supergun's scart and into scart to bnc cable. Image has a clean without color bleeding signal.

A Konami TMNT board (all other Konami boards I have work fine) still has incompatibility issue with this monitor though. Intro, cutscenes and start screen looks normal, while when gameplay starts there are heavy horizontal lines which look to move as sprites move on screen. Most of the backgrounds are blackish and change brightness as you move around. Main character Sprite looks vibrand good though.

I am sure it is a monitor related issue because a second different (maybe newer) 14 Sony BVM monitor shows everything fine and M92 boards don't have color bleeding even without pull down resistors and with RGB grounds disconnected. That second Sony monitor looks it is working with everything you throw at it and it is not picky.

I have tried TMNT on a Samsung LCD and plays fine there too. So something causes incompatibility with TMNT and my main Sony BVM monitor which I prefer to the second one because has a lot of video adjustments using knobs to the front panel plus it has a better image quality with deeper colors.

I read somewhere about 75 ohm bnc terminators that must be placed on all outputs of a BVM monitor. I don't have those but if this is the case I can find in a local shop 50 ohms in stock at 1,5€ each.

Thank you in advance for your help.
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