Wells Gardner 25k7191 Arcade Monitor

I'm putting this page up because I had a few small problems while using my Wells Gardner WGk7191 arcade monitor in my Mame cabinet. It appears that a few other people have run into the same problems, so I thought I'd keep the information here for people to find.

I am using the monitor with a VGA cable hack with the ArcadeVGA video card from Ultimarc. When I tried to run Windows 98 at 800x600 or 640x288, the display wouldn't look right. At the bottom of the screen, there was a fold where the screen would curl, and in effect I was losing the bottom part of the screen. This affected Mame games that run at certain resolutions also and runnig Windows at 800x600 or 640x288 (640x480 worked fine). On the Ultimarc message board, someone mentioned that they had fixed this same problem. (Note: this also affected certain games when I was running my monitor with the Trident Blade T64 card with AdvanceMame.)


I pulled out the fuse and took a look at it. The fuse in my monitor is "2A 250VAC". On the fuse, it also says, "BEL 3 SB". The monitor's circuit board where the fuse plugs in has "2A 250VAC" printed on it. There are little icons on the fuse for "SB" and "UL". I think that the "SB" stands for Slow Blow.

Click the thumbnails for full-size pictures.

Here's a picture of the diagram that is printed on the back of my k7191 monitor.
The schematics diagram for the Wells-Gardner Model 25K7191.
K7000 Monitor Manual (pdf)I finally got my hands on the manual for the k7191. It's in pdf format, and actually the manual is for the k7000. However, Wells Gardner sent it to someone for use with the k7191, so I am assuming that this is the correct manual.

NOTE: The schematics diagram in this manual mentions that the diagram is for the 9k7700, 13k7800, 19k7600, and 19k7900 monitors and to "Refer to other schematic diagrams for certain unique models.". See the next image for the 25k7191 schematics.
Here's close-up of a picture of the pot that I adjusted to fix the curling problem. Note that you need a screwdriver or something to adjust it. It almost doesn't look like a pot at all (to me, but I'm not experienced with this stuff at all).
Here's a zoom-out of the same pot.
Here are the outputs for the monitor cable. These are the wires that need to be spliced to a VGA monitor cable hack for use with the ArcadeVGA PC video card from Ultimarc. Note that I also added a vsync wire to my VGA cable hack. This is required in order to use the Act Labs PC USB Light Gun with the arcade monitor.
My monitor gets power from the black and white wires.
These wires go into my isolation transformer, then back out to a wall plug.

Wgk7191 Monitor - Strange Circuitboard

This circuitboard is screwed to monitor case, but isn't wired to anything. I wonder what it's for?

Somebody's asking about it, so I thought I'd post some detailed pictures. Maybe I can find out what it is.

The circuit board connected to the monitor.
Large top view of the circuit board.
Smaller top view of the strange circuit board.
Angled view.
Shot of the underside.
Hopefully you can read the capacitors.


Act Labs USB PC Light Gun is now working!

Andy Warne at Ultimarc has been running some tests with the Act Labs gun and arcade monitors. He discovered that if you use an arcade monitor and you splice the hsync and vsync wires together in your VGA cable hack, then the light gun won't work. I added a wire to my monitor's output cable for the vsync, and wired it correctly to the video card, and now I'm playing gun games on my cabinet. Sweet! By the way, according to Andy, this fact is true no matter what kind of video card you are using.

Here are some useful links:

BYOACThe build your own arcade controls has very good info on all aspects of building arcade machines. If you have any questions, there are many helpful people in the messsage board. There is also a lot of info in the huge FAQ there.
Ultimarc's web siteThis is where the ArcadeVGA card was created - totally awesome for connecting an arcade monitor to your Mame computer.

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