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new net city monitor issues when jamma wired

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mike hancho

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Hi. i just got a new jamma loom for my ew net city to convert it over. so far everything hooked up good, but the colors are off. when i hook back up my naomi, everything is fine. The monitor in my nnc is a D29cq51. but im not sure on the chassis. Does anyone know if this monitor auto syncs? Also, i took the back off and i noticed the chassis had a 3 position switch. I havent flipped it, just to make sure i dont mess up my crt, but could this be the resolution setting? Any help would be greatly appreciated.
 

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I dont think you hook jamma rgb to the VGA cable, I think you are supposed to run that to the monitor I think it has a separate input connector for that purpose. i could be wrong, cant remember all the details. Its been years since I had a NNC.

Is that a river service harness?
 
that what i had thought as well. i didnt see another spot to hook up though
 
i got it from ebay seller japan arcade. i have used alot of their harnesses and they are top quality. they are working with me and have offered a refund, but i wanted to check here before i went that route.
 
Unless it's the camera or there's something wrong with your board, it looks like maybe blue and green are swapped.

Jamma video is high impedance and the VGA cable input is low. That would only result in blown out colors. Maybe that is what's happening and it's clipping, but I'm not sure.

Can you open the hood on the vga connector and take a look that the wires are correct? The jamma side looks correct.
 
The chassis on this monitor has two inputs. You cannot use the VGA cable or its input for raw RGB video.

Alternatively and the best way to do this is straight wire the jamma RGB lines directly to the second input on the chassis (Its made for Jamma type RGB) I think its the input marked as 3V and the VGA input is 0.7v
The chassis will auto select inputs so theres absolutely nothing you need to do other than hook the board up and maybe change the power or audio cables. +
 
pinout looks good. here is what the chasis input looks like. i see 2 on the board. but they are both connected. the 2nd one only has 2 wires going into it. but im not sure wher they back off to in the cab.
 

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would it be as simple
as unplugging the not used one and moving the one that feeds off the 15 pin connector to the other pin out?
 
Dang, yeah the VGA connector looks fine.

Technically low impedance video (jamma video) is supposed to go into that other unpopulated connector.

On mine, when I have both inputs hooked up, it does work but I get interference. I ended up just using a Jammafier.

edit: the current version of the river service harness also uses the VGA input. Are we sure that input doesn't automatically impedance match?
 
Last edited:
so, if i swap both of these connectors, this should work?
 

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Yes that will fix Jamma games but VGA sources (like Naomi) will be dim.
 
Before i unhook stuff, anyone know whatvyhese 2 wires are for? there are 2 wires coming in from the 2nd harness. if i unhook and swap the connectors, do i need to unhook these?
 

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notsonic said:
Yes that will fix Jamma games but VGA sources (like Naomi) will be dim.
Click to expand...
Wasn't it the other way around? Jamma will be dim, VGA will be fine. I remember the contrast was locked to like 100, but that was wrong and you needed to bridge 2 pins on the remote board to be able to adjust the contrast.

Mike, I dont remember what the wires did, dont have NNC anymore ||
 
mike hancho said:
Before i unhook stuff, anyone know whatvyhese 2 wires are for? there are 2 wires coming in from the 2nd harness. if i unhook and swap the connectors, do i need to unhook these?
Click to expand...
I never really discovered what those are for never looked into I think if you look at the pin out diagram for that main connector it would tell you.

You can use the chassis without it connected afaik seeing how i seen a number of these without them
 
i went ahead and just unhooked the spare port, and moved the vga port over to that connection. Bam! all works now as it should. only issue is i have to open the back to swap it back overto vga if i want tomswapnit back to naomi
 
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