NeoGeo MVS 1C and K2_video NGPC system RGB output problem

[bovined]

I have a consolized MV1C system that I bought as is from someone a year ago and it was modded for S-Video. The S-Video works fine but when I tried to use the standard AV out port with the proper RGB output cable I cant seem to get it to sync properly with my Sony BVM D20F1U monitor. The strange thing is that I can get a proper output through a Frameister to an LCD by setting the sync level from 0 to 30 (not even sure what that does.) Does anyone know the issue here and how to go about getting a fix for a good RGB output signal?

I also recently obtained the K2_Video NGPC board and it ALSO seems to have the same issues in that I have an improperly synced signal to the BVM but cannot get it to show on the FM no matter what I set the sync level to. I tested with the OSSC and also cannot get any video to appear at all.

the K2 is connected with the wookiewin breakout from the unit and then using a male to make generic scart cable to the other wookiewin breakout on the BVM and I get these results:

https://imgur.com/a/vjzryej

if I enable ext sync from the BVM it seems to get worse.

[bovined]

Some are suggesting adding 470Ω resistor and a 10µF cap (Brown) to the sync line somewhere on the cable....does that make sense? do I just add these in anywhere along the line?

[bovined]

someone on neogeo forums suggested I bypass the scart cables and adapters and just used BNC to RCA connectors on both sides and simply plugged in the 4 video signals direct with RCA cables and it is now working fine to my P/BVMs! I went to the CRTs direct with my CMVS 1C and it also is working now so there must be something along the cables that is messing up the sync.

MY question now is how I can send that clean signal to either the Frameister or OSSC now?

Would it be easier to try and send the RGB + sync to the upscalers or modify the existing SCART cables to deal with the issue? I could also output the signal from the BVM back out via scart but will probably run into the same issue as far as I understand what I am seeing here.

Also what could be in the scart cables causing this problem in the first place?

EDIT: I guess I just need something like this: https://retro-access.com/products/8-pin ... -multicore

[bovined]

I ended up buying the following cable to go direct from the K2 to the frameister: https://retro-access.com/collections/bn ... -multicore and it works perfectly fine. I am no closer to understanding WHY but I am sure its the info about getting TTL level sync to the FM and PVM.

[RGB0b]

It's my guess that the resistor on the sync line fixed the issue. You can probably get a BNC to VGA cable if you'd like to use the OSSC. I wouldn't use the cable from the MVS on anything else though...who knows what's in that.

[bovined]

thanks retrorgb! I did test a BNC to VGA cable but the one I had had H/V sync cables so not sure how to combine that to use the one sync output from the K2. Do you know what the best way to try and test this cable would be without an extron? Love the content btw as always and keep up the great work!

[RGB0b]

Well, you can test with a multimeter to see if there are any components in it. Where are you located?

[bovined]

I followed your video retrorgb and there does not appear to be any components on the cable as my multimeter readings all show zero on the sync lines. I am located in the san francisco bay area.