Neo Geo MVS sync issue

[Asayuki]

You said you can measure the amplitude of the sync signal. Do you see that on a scope? If yes, can you sync to the vertical pulse and post a screenshot of it?

[DaveyD]

Are there any jumpers on the monitor chassis?

I used to have a WG D9800 that had a similar issue what you are experiencing, except this was with IGS PGM games. Everything else worked perfect workout issue. In the end i found out there was a sync jumper on the monitor chassis that I would have to swap over to play the IGS PGM games

[Zebius]

Okay just tried to bridge H and V sync, result is a black image so not the desired result unfortunately.

There's an old thread http://forum.arcadeotaku.com/viewtopic.php?t=14 where it's
mentioned that for MVS the 2 sync inputs have to be bridged and it's also in the manual (page 2)

There's also the impedance switch, are you sure it's set to 1KOhm?

[Sp33dFr34k]

Okay I have to make a correction, Grant was telling me to bridge the vertical sync, not video sync, my bad

Next to that, I noticed something fishy going on with the vsync pin on the VGA connector (it was sliding inwards a bit when connecting, never noticed because of the hardplastic shell) I used and decided to grab another one and give the H-V sync bridging another go while I was at it.

To my surprise it works perfectly fine now, the image is stabilizing pretty quickly as opposed to before.

Many thanks for all the help here guys, really appreciate it!

[PascalP]

Okay I have to make a correction, Grant was telling me to bridge the vertical sync, not video sync, my bad

Next to that, I noticed something fishy going on with the vsync pin on the VGA connector (it was sliding inwards a bit when connecting, never noticed because of the hardplastic shell) I used and decided to grab another one and give the H-V sync bridging another go while I was at it.

To my surprise it works perfectly fine now, the image is stabilizing pretty quickly as opposed to before.

Many thanks for all the help here guys, really appreciate it!

And the build quality of WeiYa strikes again...

[Sp33dFr34k]

Blame the Aliexpress VGA connectors

[Asayuki]

I'm happy you finally solved it.