C-Sync Polarity for PVMs or other RGBs displays may be incorrect

[Liz1701]

I've found that the C-Sync Polarity is incorrect for Sony PVMs. Using a CGA card, apparently CGA has HS and VS as both Positive. I took C-sync from the MCE adapter and ran it through a 7404 Hex Inverter to get Negative C-Sync.

EGA Mode 1 is also supposed to have HS and VS as both Positive, so this method should also correct it to Negative C-Sync.

MDA and EGA Mode 2 are supposed to have mixed polarity on HS and VS so one would have to invert the sync that is Positive before combining the sync.

My PVM will only accept 15khz Negative Sync.

Just wanted to add this note, so if anyone is having issues getting an image. You may need check the Sync Polarity and correct for your display.