Donkey Kong Jr.


Last May I picked up a second Donkey Kong cabinet from an old high school friend. The cabinet was complete with the exception of a monitor and if not picked up, was headed to the curb on garbage pick up day. I picked up the cabinet with the intention of making it a dedicated Donkey Kong Jr game so I wouldn’t have to swap boards in and out of my original Donkey Kong cabinet anymore.

Fast forward 7 months and the cabinet has not been touched and is sitting in my garage. Much to my wife’s displeasure, this kept me from moving the lawn furniture into the garage over the winter! Over the weekend, I decided to move the cabinet into the basement and start working on it. I did not move the lawn furniture into the garage.

I shopped around for a few months looking for an original Sanyo 20ez monitor to put in the cabinet but didn’t have any luck. I found one on E-bay that went for more than I was willing to spend and had a few offers to ship monitors to me but they all needed some form of repair. I decided to use a spare Wells Gardner K7000 monitor that I had sitting around. It took me all of 5 seconds to realize that the mounting holes on the K7000 monitor did not line up with the mounting holes on the Nintendo mounting brackets. As a matter of fact, the K7000 did not have any top or bottom mounting holes at all.

It became apparent that I would have to bolt the monitor to the monitor shelf in the cabinet. I took a few measurements to find the center of the monitor shelf and also the center of the monitor itself. I then measured the distance that the monitor in my Donkey Kong cabinet stuck out from this shelf (towards the front of the cabinet). The monitor was bolted to the shelf in almost the exact orientation as the monitor in my Donkey Kong cabinet. If I had to guess (because I didn’t measure) the monitor in this cabinet probably sits a bit lower than the monitor is supposed to but once everything is done, I don’t think it will be apparent. Here are a couple of pictures of the monitor bolted into place:

In the first picture above, you can see the original Nintendo monitor mounting bracket at the top of the monitor. You can also see that the K7000 sits short of this bracket. In the second picture you can see the bolt locations on the lower left and right sides of the monitor frame. There are also two bolts at the top that can’t be seen in this picture.

Once the monitor was mounted, I needed to find a spot to place the 120 volt isolation transformer for the K7000. 20ez monitors used 100 volt transformers so I couldn’t use the one currently located in the cabinet. I located a spot near the power supply for the isolation transformer, mounted it and then connected it to the 120 volt and ground terminals of the terminal block. Here’s a picture of the isolation transformer mounted inside the cabinet. The isolation transformer has the 4 red wires attached to it…two coming in from the terminal block and two going out to the monitor. The terminal block is to the far right of the picture:

One thing that is needed on monitors in a Donkey Kong/Donkey Kong Jr cabinet is an inverter board. Without an inverter board, the image on the monitor will appear to be a negative of what should actually be there. The majority of the image will appear to be white if the inverter board is not present. I had previously purchased an inverter board from Mike’s Arcade and made the necessary connections to it.  The inverter board required 12 volts DC to run, so I temporarily “borrowed” 12 volts from pin 4 of the 9 pin CPU connector at the power supply.  After a bit of monitor tweaking, the image is stable and clear…my blurry picture does not do it justice:

The final picture above is the front of the cabinet that will eventually become my dedicated Donkey Kong Jr machine. It is complete with a Donkey Kong marquee and bezel but those were removed while I worked on the monitor. Right now, the wiring to the inverter board and monitor is a bit of a “hack job” as I wanted to test everything before making it permanent. I will eventually clean up the wiring and add molex connectors as time allows. As usual, a dedicated photo gallery has been set up for work on the Donkey Kong Jr cabinet.

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