Save Me JEEBUS

sbardelli

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Hey guys...

I am restoring a Jump bug that was converted to Mr. Do!

Everything was finished, except I didn't have a Jump Bug PCB.

Well, I finally bought one. It came with an edge connector that also connected to a Jamma Harness.

So I had two options.

Re-wire the Cabinet to OG jump bug... or re-wire with a Jamma harness.

I opted for Jamma. It seemed easier.

So I took a jamma harness, wired up the essentials (+5, ground, +12, -5) and re-wired the control panel.

Sent the wires to the monitor.

There were a few connectors that didn't go to anything.

I turned it on and have a super-blurry... and very unstable looking picture on the screen.

I can see the twinkling "stars" of the background, but the main image is severly distorted.

It looks like a sync. issue, only its not scrolling.

Is there something I should have hooked up, but didn't?

I thought it was a monitor/picture image... so I tweaked a bit with the red, green, blue and sync wires. Nothing. Also, the cabinet I stole the jamma harness from had the same monitor. A k6100.

What could I be missing? What needs to be wired in to make a Jamma harness work?

Like I said, there were some connections that I didn't hook up. Seemed like coin door stuff... nothing important.

What should I try next?
 
Are you sure it's a K6100? That's a vector monitor and they're raster games?

Have you been licking frogs again??
I'm not NOT licking frogs...
 
I can also tell you that the MR. Do was working just fine.

So I'm thinking it's not a problem with the monitor per se...

It's more of a "I didn't hook something up right/I forgot to hook something critical up" problem.
 
Check video ground is actually connected, with a harness in the way there's a high chance it's not connected. Many people don't bother with the jamma video ground pin specifically and connect it to pcb ground. Any connection to jamma pin 14 is probably swinging in the breeze on the other side of the harness.
 
Check video ground is actually connected, with a harness in the way there's a high chance it's not connected. Many people don't bother with the jamma video ground pin specifically and connect it to pcb ground. Any connection to jamma pin 14 is probably swinging in the breeze on the other side of the harness.

Thanks for the tip. I know for a fact it's swinging in the breeze. Didn't think it was critical.

Where should I ground it on?
 
Check video ground is actually connected, with a harness in the way there's a high chance it's not connected. Many people don't bother with the jamma video ground pin specifically and connect it to pcb ground. Any connection to jamma pin 14 is probably swinging in the breeze on the other side of the harness.
The monitors video input ground.
 
Tie it to any ground on the JAMMA connector.

Some boards do this themselves, others expect the harness to do it, and if neither does it then it swings in the breeze.
 
But where does it go to on the board? The video ground input on the monitor needs to be tied to ground on the game PCB, ie a connection all the way through. If you have it wired to the video ground pin on the JAMMA loom in the cabinet, potentially does not connect to any point on the board as the home made harness on the board may not be 100% correct.

If that is correct then take the PCB and its harness out of the cabinet and check that all the grounds are connected to each other, specially the ground plane on the solder side and the ground plane on the parts side. Some game PCBs do not join all the grounds together at the board, as they assume the cabinet wiring will do it, Ms Pacman is a prime example of this. In that case the game runs but the video is weak and washed out, and the game will usually crash when you power up. Worth checking on your board too. Amateur harnesses are a minefield for this kind of stuff.
 
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But where does it go to on the board? The video ground input on the monitor needs to be tied to ground on the game PCB, ie a connection all the way through. If you have it wired to the video ground pin on the JAMMA loom in the cabinet, potentially does not connect to any point on the board as the home made harness on the board may not be 100% correct.

If that is correct then take the PCB and its harness out of the cabinet and check that all the grounds are connected to each other, specially the ground plane on the solder side and the ground plane on the parts side. Some game PCBs do not join all the grounds together at the board, as they assume the cabinet wiring will do it, Ms Pacman is a prime example of this. In that case the game runs but the video is weak and washed out, and the game will usually crash when you power up. Worth checking on your board too. Amateur harnesses are a minefield for this kind of stuff.
Honestly, I don't think the problem is the harness. It was made by the dude at Eldorado games. He is pretty much an expert.

And, when I take the pcb, harness, and plug it into my Ikari warriors set up, it works just fine.

There is something I didn't hook up right... and I think it has to do with the extra wires I have left over.

I'll get a list of wires that arent' hooked up at this point.

From what I could tell, it was coin door stuff... speaker stuff... and test button stuff.
 
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