Wells Gardner D9800 issue, no idea what the problem is

[Adamn]

First, I sincerely appreciate any help that anyone can offer me.  It's much appreciated!

I have a WG9800 monitor that's served me well in my Dance Dance Revolution arcade cabinet.  It's worked great via VGA.  I'm looking to attach a different PC to it using a Radeon HD3400 Pro video card, with a LFH-59 --> VGA output.

 - When attaching the VGA cable to an LCD PC monitor, it works fine.  Confirmed resolution at 640x480
 - When attaching the VGA cable to the VGA port on the WG9800, (LFH-59 on PC --> VGA cable --> VGA port on the WG9800) it does not detect the monitor - says "no signal" with an overlay on the screen, and shows wavy lines like there's a sync issue.
 - Attaching another PC via PC VGA --> WG9800 works fine.

I'm completely lost - no idea what could be causing this.


Thanks in advance for any help you can provide!  I pay forward any knowledge I gain and help others any chance I get. 


***EDIT*** Additional information that may be relevant - when I connect a VGA from one of the LFH-59 VGA outputs to the LCD PC monitor, I get picture.  If I then attach a VGA cable from the second half of the LFH-59 to the WG9800 VGA port, BOTH images go out.

***SECOND EDIT*** After much troubleshooting, I've tried uninstalling the ATI drivers for the card, booting in safe mode, and still no effect.

[Gray_Area]

The wiring of the video port and the adapter are different. Maybe only one wire different. Or, your card port is 60-pin; the 59-pin adapter won't work.