Custom Megatouch XL Cabinet

Here's a rough mock-up of what I'm trying to accomplish. The sides are 16" X 16", with 30 degree beveled edges. You can see that there is barely enough room to fit everything in. If I was going to do it again, I would have added 2 inches to each side.

The 15" LCD touchscreen I bought on ebay will be mounted in the front panel with the Megatouch motherboard mounted to it. The back panel will only have some type of air vent near the top. The AT power supply will be mounted to the bottom panel along with a fan and buttons for entering the Megatouch setup and screen calibration menus.

I have a problem cutting straight lines. I think I try to move the saw to quick, and end up causing the blade to angle. I really wanted the monitor opening to be straight, so I decided to use my router with a pattern cutting bit. I didn't take pictures when I did it, but here's a description of what I did.

First I measured the opening in the plastic monitor frame, and drew it on the front panel piece. Next I screwed some straight pieces of wood along the lines I drew, so I knew they were straight. I screwed them to the backside of the panel, so I wouldn't need to fill any holes.

This is a picture of a pattern cutting router bit. I used a hole saw to make a starter hole near one corner of the screen opening. Next, just run the router along the inside edges of the wood, and you end up with a perfectly straight cut.

An added benefiet of using the router is that it makes a nice rounded inside corner!

Here's the monitor opening with rounded over edges, painted with primer and sanded.

The back of the front panel has been routed to fit the monitor. First, using the same method I used to cut the center out, I routed the area for the touchscreen glass to fit snug so it won't move around. I routed about 1/2 inch deep, so there's about 1/4 inch thicknes left over. I'll add some foam tape around the opening before I mount the glass.

I also routed out additional areas to allow the touchscreen wires to clear, and for the LCD metal chassis to sit on top of the touchscreen glass.

This is the top of the back panel. I bought a 7/8" dowl and cut it down the center. I then glued the half dowl to the top of the panel, so when It's attached to the front panel there will be a nice rounded edge.

Here you see a trial fit of the front and back panels. This is what the final product will look like.

You may notice that there isn't much room inside. It looks like I'll have to mount the screen before I attach the panels. This is going to make it necessary to do some bondo work with the screen mounted, making it possible to get dust inside. I'm not looking forward to that, but don't know how to get around it.

As I said before, if I had it to do again I'd make it a couple inches bigger .

This is the monitor sitting in the front panel. Notice how close to the top the monitor is. That's why I may have to do some sanding and painting with the monitor mounted in place. I guess if I do that I can tape up the monitor so no dust gets inside.

I also routed a little too deep, so there is a small gap between the wood and the metal that the mounting screws go through. I should still be OK, I'm sure I can find something to use as a shim. Even without shims as long as the screws aren't too tight it should be alright.

I'm now making the vent in the back door to let the hot air escape. There will be a metal grill in the slot.

The process is similar to the one I used on the front panel. I've drilled some holes for the outside corners of the vent, and then screwed down 2 pieces of wood to act as guides for the router with pattern cutting bit.

Now that I've glued the front and back panels together, you can see just how close it got inside. I wedged the wires into the I/O board connector, and could have bent the pins over a bit to make more room. After looking at it I decided that it's better that they're close, so they won't fall out if the get loose.

NOTE: I later found that I had wired the calibration and setup switches wrong, and fixed it. Don't use this picture to figure out where the wires go, as they are wrong in this shot. It won't damage anything, but you won't be able to get into the setup menu.

This finally gives an idea of how the final product will look, although without side panels. The angle of the screen should be just right when placed on a counter top.

I added 3 screws from the back panel into the reinforcement triangle piece to help hold it together. It does wiggle a little bit if I pull on a panel, but not much. Once the side panels are on, it should be rock solid.

Here's what it will look like. There will be T molding around the sides, and felt on the very bottom so it can be turned towards the player. At this point the bottom and side panels are just resting together, they haven't been glued.

Now that I've got the panels together, I think the side panels are a bit too big. I designed it that way to have 2 inches of space below the cabinet so the fan would have ample room to intake air. Looking at it, I probably should have made the sides with 1 inch overhang instead of 2. I'll have to think about whether I want to try and adjust the sides, or just leave it the way it is.

Upon testing the electronics, I found a few problems. The sound didn't work, the software setup button didn't work and biggest of all - I couldn't calibrate the touchscreen. I fixed all the problems, and this is a shot of the final test before gluing on the right hand side panel.

The sound is working now, and all I can figure is that the on board volume pot was dirty and it was fixed when I moved it back and forth several times.

The setup button problem was due to me flipping the wiring diagram on the I/O board when I drew it out. It didn't hurt anything, and all I had to do was swap the wires around to fix it.

The touchscreen calibration was the tough one to fix. I had the touchscreen panel resting on foam that I placed around the monitor opening. It seems that the pressure of the assembly when screwed down was pressing on the edges of the screen, where the 'active' portion that senses touch is located. To fix it I had to remove everything from the wood panel, scrape off the foam and then cut 1/8th of an inch thich stringers of posterboard. I then stuck the posterboard along the very edge of the monitor opening, so the touchscreen panel sits on the thin posterboard instead of thick foam. This took care of the calibration problem.

Here's a closeup where you can see all the layers I came up with to fix the touchscreen problem I was having.

On the outside is the wood of the cabinet monitor opening, next is the thin piece of black posterboard, then is the touchscreen glass.

Now I had to glue the right side panel to the rest of the cabinet. I wanted to get the feet as close to level as I could, so this is what I came up with.

I'm using the side of my Tempest cabinet as a straight edge. It's about the biggest thing I could find that was straight.

I flipped the cabinet over and gently placed it on the right side panel, while trying to line it up as close as I could. Then I did some minor adjustments by sliding the cabinet flush up against the Tempest to make sure all 4 feet were in contact with the Tempest.

I then placed a box with some weight in it on top of the cabinet, and wiped off the little bit of glue that squished out onto the side panels. After it has sat for several hours, I'll add a couple screws for extra strength - assuming I can still fit my drill inside to pre drill the holes.

After this all that remains is attaching a couple wood strips that'll be used to screw the bottom panel to, paint the side panels, apply the T molding and attach some felt to the feet so it can be swiveled to face the player.

I've started final painting. I'll do 3 coats of blue on each side. This picture shows the 3rd coat on the left side, and I haven't started on the right side yet. The paint I'm using says to wait 4 hours between coats, so it may take a few more days to finish.

Now we're getting close!

Now for the description of the hardware. Here is a Merit Megatouch XL 'Telco' brand motherboard. It has 3 pieces, the motherboard, the I/O board and the riser board that connects the two.

I've outlined the CR2032 motherboard battery in this picture. It's a good idea to replace it, because if it's the original one it will either be dead or close to it.

The motherboard ports from left to right are: keyboard, mouse, com1, com2, parallel and video. The touchscreen goes into com1, the original Megatouch also has a network jack that plugs into com2. I don't know what the parallel port is for.

Here's a closeup showing where to wire up buttons to be able to access the software setup menu, and the touchscreen calibration.

Just connect one lead of a momentary pushbutton to a ground, and the other to the specified pin. I'm sure one of the other pins will add credits to the game, but I've got mine set for free play.
If you don't have a button handy, you can strip both ends of a piece of wire and carefully touch one end to a ground pin, and the other end to the setup or touchscreen pin.