Gauntlet: It’s ALIVE!!!

June 2nd, 2010 Posted in Gauntlet

Two weeks ago I received the last of the arcade parts (for now : ), and invited Xiv over to help me calibrate and test out the games.

I first hooked up the Arcade VGA to get the drivers installed, and with the DVI to VGA converter, I was able to see the picture on the VGA Monitor while I did this.  After the drivers were installed, I shut down the PC and hooked the Arcade VGA card up to the J-PAC (JAMMA to USB converter).  I turned on the arcade monitor and fired the PC back up, and we got a whole load of back and forth shifting of video.  We played with the vertical sync and horizontal sync a bit, but I was concerned because there was an amber LED lit up on the J-PAC board, and that it possibly meant that there was an issue.  So we opted instead to plug the card into the VGA monitor I had, and go through control panel “testing” (aka. play a bunch of video games).

Unfortunately, something with the Arcade VGA drivers seemed to be messed up, as any game we’d fire up would be choppy and the audio would be unintelligible.  The previous video card I had in it (an ATI AGP card) worked fine, so I rolled back the system with a system restore, pulled the Arcade VGA card, re-installed the crappier AGP card, and fired the machine up.  No problems.  Not caring to deal with the video sync or video card issues, I tabled those sub-projects and we got our game on.

Fast forward to yesterday. After letting this sit around for a week and a half (and working on some other (neglected) projects), I got back to work on the Gauntlet machine.  I had exchanged a few e-mails with Andy @ Ultimarc, to see if he knew why the drivers on the Arcade VGA had fucked up the performance of my machine, and he wasn’t sure.  He did confirm that the amber LED on the J-PAC board was normal though, so I figured I’d give things another shot. But first I was going to see if I could resolve the sync issues.

I powered on the monitor and the PC, and quickly found out that by playing with the Vertical Sync, Horizontal Sync and Horizontal Position, I could get a somewhat acceptable image, however the image wasn’t staying still.  For example, if dialog box popped up on the black desktop, the screen would start flipping left and right and/or up and down.  I thought this might be because I was still using the AGP video card, so I tossed the Arcade VGA card in.

Unfortunately, this did not solve anything.  I was still having sync issues.  I even tried testing the continuity on the composite video sync wire (coming off of the JAMMA), but that was good. I wasn’t getting system slow down this time (from the video card), but since I couldn’t test it in game, I couldn’t be sure.  I decided to sleep on it and tackle it later.

Today, I got home and looked hard and long at the machine.  I started tracing wires.  Off of the JAMMA board I had a red wire for red signal, blue wire for blue signal, green wire for green signal, a black video ground wire and a brown composite sync wire. There were two unused wires from the video harness, a white wire and a purple wire, for vertical sync and horizontal sync.

I followed Red to red.  Blue went to blue. Green went to green. Black went to black. Brown went to another Molex connector that was not connected to the monitor chassis, even indirectly (this connector was daisy chained off of the Molex connector I was using, so it had RGB and ground going to it as well).  The purple and white wires were hooked up to the Molex I had connected.  It was an A-Ha! moment. So I needed to hook up the Brown composite sync wire to the monitor chassis, but where?  There were four pins on the chassis that would make sense: Positive Horizontal Sync, Positive Vertical Sync, Negative Horizontal Sync or Negative Vertical Sync.

The brown wire was wired to the Positive Veritcal Sync slot on the Molex connector, so I figured that might be it.  I fired up the machine and the sync was still bad (was synced vertically, but flipped horizontally depending on the image displayed).  Stumped, I looked up at the monitor control diagram inside of the monitor and noticed the following passage “WHEN USING COMPOSITE SYNC USE HORIZONTAL SYNC INPUTS”.  OK, but which one?

Since the brown was already wired up to the positive vertical sync, I popped the pin out and moved it to the positive horizontal sync, housed in the same connector.  Fired it up, and the image was stable!  …Except not centered correctly.  The image looked like the offset filter in photoshop.  The edges of the image were in the center of the screen and the center of the image was on the outside corners of the screen. I tried playing with the horizontal and vertical position knobs, but no go.  I couldn’t get the picture to move over that much.  So I turned to the internet.

In a stroke of serendipity, Google led me back to Mr. Bob Roberts (from whom I had purchased a good deal of my replacement parts), in a page where he breaks down monitor sync issues. After a quick scan, it seemed obvious that I needed to hook up the composite scan wire on the JAMMA board to the negative horizontal sync pin on the monitor chassis (for those that are wondering and for the aid of Googlers out there like myself, the Gauntlet cabinet has a Wells Gardner 19k4914 monitor in it).

I hooked the wire up to the pin using a hook-up wire, fired up the PC, and it looked VERY promising.  Shit wasn’t moving around like before.  Once XP was fully booted, I started fiddling with knobs and BINGO!  It works!  Of course I had to fire up a game:

What’s next? Well hook up the rest of the controls to the I-PAC2, and start fastening shit down. Then it will be time to work on the permanent control panel!

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