JVC rgb mod issues, need help

[Santeegmc]

Hoping someone can help solve an issue I'm having.

After throwing cation to wind, I went ahead and rgb modded my old JVC AV36020. I basically followed
deezdramas mux mod viewtopic.php?p=1483331#p1483331

My board was slightly different with the pin locations but the mod does seems to work....ish.

My feed is coming from an Atomiswave with a jamma connection. Its actually a functioning arcade cab, the current monitor is kinda faded and tends to give off some nasty pops occasionally. Game is sports shooting usa. I disconnect the cab monitor and wired up the JVC. Rgb goes to TVs new rgb, ground to new TV ground. For the sync, i spliced a rca connection and connected it to video input. The Sync ground is connected to outer wire of the spliced rca and also tide to the new TV ground .

My issue is that the when turning on the Atomiswave a few seconds after the main screen appears the tv will cut out. The screen goes black and the power light blinks. I then have to unplug the JVC for it to reset. I found if I wait until the main attraction screen (i can tell by the audio) and then hit the rgb switch, it will continue to work just fine. Also at some transitional screens during game play, mainly when the game starts a new level it will cut out again.

Could this be a wiring issue? I'm hoping it something with the sync, it's the only line that doesn't have a resistor. Perhaps the sync ground doesn't get tied into the other rgb grounds?

To make things more complicated, I decided to splice the wires into the original monitor harness and run both at the same time. Fixed the whole cutting off issue, but the picture on the JVC has an unstable/scrolling video on it. The original monitor works fine.

Any help would be very much appreciated. Figured this would be the place to ask.

Main goal is to get the old behemoth working and create a cab with some good happ lightgun games. It really does look amazing when I got it to go. Sammy sport shooting usa is much better on a big screen.

[KPackratt2k]

The sync coming from your arcade PCB is most likely TTL level (5.0vp-p), which is beyond the voltage level that your TV is designed for. Try adding a 470-1000 ohm resistor inline on your sync and see if that fixes it.

[Santeegmc]

I tried a 1000 ohm resistor in the sync line but it still blacks out on power up. If I wait untill the menu it will then cut off right before the level starts. So I guess at curtain parts of the game it send too much current.

Can I read my sync output power with a multimeter?

Maybe I have the wrong value resistors for the rgbs?

[Santeegmc]

I Made some progress.
I decided to add the same resistor set up as the rgb to the sync. Passes through a 510 and then a 180 is linked to the ground. Same problem as before.
Hooked up to a multimeter, while running the Atomiswave shows roughly 4.4v on sync before the resistors. Shows 1.1v after. I continued to watch the reading thinking I'd see a spike when the TV cuts out. I did not. The signal stayed a constant 1.1v before, during and after the TV shut off.
Figured I'd try using the vga output on the Atomiswave, spiced into rgb, sync and ground and sure enough it solved the problem.
I'm wondering if it ocastionaly sends a signal through ground on the jamma connection? Or a negative sync signal? That could cause the TV to freak out.
Ideally I'd like to get it working with the jamma and eventually a jamma switcher for multiple games. But for now I can atleast play it.
Next hurtle is figuring out how to adjust the screen postion. It's a little off to the left. Can that be done with the remote through setting?