Author Archives: Chupperson
I have been working on a Wizard of Wor machine that wouldn’t start. The only thing I got was a vaguely green screen and a buzzing speaker. I began by removing the socketed chips one at a time and cleaning them with a high quality plastic eraser and a Dremel wire brush when the tarnish was too heavy. After this I sprayed Deoxit into all of the sockets and reseated the chips several times each.
I checked the power supply and found that there was no voltage on the +12v line. If all voltages are not present, the supply will not send the 5v “power good” signal and the game will not boot. My first thought was to replace all the capacitors on the power supply since they are at least 37 years old at this point. However, I still didn’t get any change. I also tried changing out the variable regulator that controls the 12v to no avail.
It was suggested to me that the small tantalum capacitors on each of the 6 game PCBs are known to short out. While I was testing another point on the power supply, one of these capacitors on one of the game’s two RAM boards exploded, so I went ahead and replaced them all with these. After that the game booted!
However, the display was completely scrambled. Another tip I got was to adjust the horizontal frequency control deep in the recesses of the monitor chassis. Turning it all the way up, I was finally able to get a steady picture, but it was a bit unevenly projected, most likely due to old capacitors. There were also two sets of vertical yellow lines at even intervals across the screen. The cause of this turned out to be some bad RAM chips.
To test the RAM chips, I burned Mark Spaeth’s excellent GORF test ROM since Wizard of Wor uses the same hardware. I had to create an adapter to burn it onto a 2532 EPROM because my programmer isn’t compatible with them out of the box.
I also had to bend a pin out and wire a jumper in place so it would not be damaged by the ROM board (which still uses the original mask ROMs.) I found this information in the readme file for an earlier Wizard of Wor test program, WOWMD.
Now the game is up and running. I need to replace the capacitors on the monitor to correct some display geometry issues, and that’s it. I’m also planning to put heatsinks on the game’s special Astrocade chips since those are known to sizzle, and without them we’d have a dead game on our hands. Since the originals heatsinks that Midway used are pretty hard to come by now, I found some alternatives I think will work nicely for about 50 cents each.
I’ve been doing a lot of work recently getting a Mario Bros. arcade machine back into working shape. Pretty much everything that commonly goes wrong with this game had happened. The monitor’s capacitors were dying, the sound didn’t work, the internals were covered in a thick layer of black dust, the list goes on. Here is a rundown of my efforts.
The most noticeable problem was the washed-out picture, with bars of light across the screen whenever something was drawn. I picked up a capacitor kit from Ian Kellogg to replace them with. The monitor that comes standard on pretty much every Nintendo cab is a Sanyo 20-EZ. It has quite a few caps to replace. It’s probably not strictly necessary to replace them all, but with 30+ year old caps that have rubber seals, it’s definitely a good idea. The cap kit also comes with those necessary to rebuild the sound amplifier.
Something that happens a lot is that people either accidentally or ignorantly remove the grounding pin from their AC plugs. Since a lot of arcades in the 80s probably didn’t have wiring that was up to code, a lot of outlets just had 2 prongs. I’m sure many people didn’t understand the importance of grounding to keep from being shocked or overheating your equipment. I went and got a replacement plug for about $2.
When I got this to my garage, the last person that worked on it hadn’t closed both control panel latches.
This cabinet used to be a Donkey Kong Jr. machine, but at some point in the distant past, it was converted into Mario Bros. This cab is thinner than the dedicated Mario Bros. cabs (which are black in front and generally referred to as “wide body”). When Donkey Kong Jr. stopped making money, an arcade operator could call Nintendo, and a tech would come out with a conversion kit (or “Nintendo-Pak“) and perform the conversion. On this cab, they left the original DK Jr. serial number plate and put the Mario Bros. plate to the left.
It seemed wasteful to me to try to get a new control panel, so I went to find matching tape to reinforce the vinyl overlay. It cracks at the bottom because there’s no adhesive keeping it stuck to the sheet metal at that point. The green Duck Tape is almost a perfect match, while the blue is lighter, but it gets the job done.
At this point I also removed all the nuts and bolts, cleaned the control panel, and disassembled the joysticks. I cleaned them out using lighter fluid to remove the old black caked on lubricant grease, and I just used some Super Lube machine oil to get them moving smoothly again. People also use dry silicone spray lubricant or new grease, but the oil is holding up fine for me so far.
Another problem to fix was that the sound wasn’t working properly. The only sounds were those of Mario and Luigi walking, which are actually created by an analog circuit. The rest of the sounds are generated digitally through an M58715 custom chip. These are hard to come by these days but it’s possible to replace it with an 8039 MPU, tying pin 7 on that chip high. I got one from Twisty Wrist Arcade. At this point it also becomes necessary to burn a new sound ROM because Nintendo’s instructions to the original custom chip are slightly different. I got a 2732 EPROM and burned the patched ROM to it. These chips were socketed on the board which made this part extremely easy.
Next thing I got done was the monitor. Removing the front plex I was greeted with an endless sea of dust. Removing the monitor from the cab isn’t the easiest task in the world, and some people prefer working on them while still in the cab. There wasn’t enough room or light for me to try that, so out it came. I disassembled the monitor and dusted everything off, and began replacing the caps. It took about an hour to get them all replaced once I had everything taken apart.
I always like to see old PCBs where the traces were designed by people. It gives an organic feel to an inorganic medium.
I really can’t even convey how much better the monitor looks after getting recapped. With all the adjustments done it looks practically brand new. I think these photos were from before I cleaned the front plex as well.
Speaking of cleaning the front plex, since it’s not glass, you do have to be really careful not to scratch it. I used a microfiber cloth with some CD cleaning spray on mine, although some people do like to use Novus 1 plastic polish or something similar.
Last was the marquee light. The old light was long gone, replaced by one that was much too long to fit, but was mysteriously left in the cabinet anyway. The starter also looked shot, so I had to find both. The original bulb, a 10-watt FL10D, is designed for the 100-volt Japanese fixture and is somewhat hard to find. Likewise, the starter, an FG-7E, wasn’t in stock at my local supplier. However, a standard F10T8 bulb seems to work fine. I ended up using an FG-1E starter which has the same size screw base and is compatible with 10-watt bulbs.
I also carefully removed a lot of gunk from the cab with lighter fluid and a razor blade. It looks much cleaner and nicer than before and I’m very happy with how it’s turning out.
New product alert! I finally had enough time to create a replacement AA battery cover for the fabled Super Nintendo accessory, the Super Scope. If you need a replacement battery cover, it’s available at my eBay store!
I’m always working on new 3D printed replacement parts for game systems and accessories. Let me know what parts you’re still looking for!
I’ve added battery covers for the vertical Game & Watch multi-screen units to my offerings. You can find them with my other items on eBay.
Game & Watch Wide Screen battery covers are now available in my eBay store!
If you’re missing the battery cover for your Game & Watch and can’t play, we have new 3D-printed replacement covers waiting for you!
This battery cover is for the classic “Wide Screen” model, which includes Octopus, Fire, Chef, Manhole, and others. Covers for other Game & Watch models are coming soon!
I’ve been working on these for a while, and they’re almost ready to roll.
I’ll be ready to release my 3D-printed Nintendo 64 Expansion slot covers in a few weeks. I’ll also be working on the bottom EXT. cover soon as well.
I’m also working on modeling more products like the other battery covers and accessories you guys have suggested. Thanks for your input, and keep sending suggestions!