Sean Riddle's Arcade Video Game FAQ 8/9/98

Last Update 10/6/05

Sean Riddle

seanriddle {at} airosurf {dot} com


0. Who are you and why did you write this?

I am a computer programmer in Oklahoma City. My wife bought me a Williams Joust machine several years ago. This was my favorite arcade game from high school and college (I won a Joust T-Shirt for setting the high score once). I was content to just play Joust on it (silly me) until I got on the 'net and started reading posts on the newsgroup When I found Doug Jefferys' multigame info, I started hacking it up. Not too long after I put up my web page and started documenting my hacks, I started getting email asking me some of these questions. You'll notice a definite leaning towards classic Williams, Midway and Cinematronics games, since that's what I have and know best. All the electronics knowledge that I have I learned on my own, much of it while hacking my video games.


1. Can I play these old games on my PC?

Of course! There are commercial and public domain arcade games available for PCs, Macs and other platforms. There are 2 main types: games that are rewritten and game emulators. Until recently, the first type was about all that was available. PCs are now fast enough for the second group. The difference is that someone has to reprogram the first type of game from scratch. This means that the programmer has to really know the game inside and out to capture the gameplay perfectly and replicate all the quirks of the original. Microsoft Arcade's games are like this. Very well written, but not identical to the real arcade versions.

Arcade game emulators are programs that duplicate the functionality of a video game, from the CPU on up. Then the actual game program that ran on the original game (known as the ROM image) runs on the emulator. This is a more difficult way to go, since the programmer has to first emulate the CPU, then all of the hardware on the video game. The beauty of this approach is that the game can be identical to the original. Also, much like my multigames, it isn't too difficult for an emulator to run several different games.

Some of the first good video game emulators came from Digital Eclipse. They produced Defender, Joust and Robotron for the Mac. These played just like the originals, down to the 'rug' RAM test when the game starts up. Digital Eclipse went on to make Williams Arcade Classics for the PC- they added Stargate (now called Defender II due to copyright problems), Bubbles and Sinistar all on one CD along with some cool pictures and interviews with the programmers of the arcade games. (There are also a few hidden goodies.) They also released "Midway Presents Arcadeís Greatest Hits The Midway Collection 2" (Whew!) which contains Joust2, Splat, Blaster, Moon Patrol, Spy Hunter, Burgertime and Tapper.

Many people started work on their own emulators, including Sparcade and Cinemu, just to name a couple. Then a package came out called MAME that incorporated more games with each release. Itís currently up to nearly *4000* games! Hereís the official home page:


For each game you want to play on an emulator, you need ROM images. These are the programs that the arcade game executes, along with the graphics and sounds used for the game. Commercial emulators come with the required ROM images, licensed for use with the emulator. (Sometimes you can hack in other ROM images, too!)

Public domain emulators donít come with any ROM images. This means that a PD emulator alone isnít much fun. There are dozens of sites on the web that provide ROM images for hundreds of games, but remember that these are copyrighted games. If you grab the ROM images off the Ďnet and enjoy playing them, the original developers and arcade game manufacturers arenít making any money.

Anyway, many people find that after playing an emulator, they want the real thing. These programs are cool, but they donít provide the true feel of playing an arcade game. Part of it is the smaller screen or more awkward controls, but part of it is psychological- thereís something about having a real, solid video arcade game.


2. So, where can I buy a real arcade video game?

I don't sell games, but many people on the 'net do. Check your local paper's classifieds- you might be surprised. Also ask on the newsgroup Be sure to tell where you are located. There are video game auctions held frequently as well. Check with Super Auctions at or (714) 535-7000. They visit cities like Fullerton, San Diego and San Jose, CA; Dallas, TX; Pennsauken, NJ; Atlanta, GA; Orlando, FL; St Louis, MO; and Detroit, MI. Auctions can be a great place to get games, but sometimes the prices go crazy. It's always fun to show up for the inspection (remember an extension cord!) and check out the games for a couple of hours before the auction. Super Auctions charges 10% buyer's premium and sales tax, so be careful with your bids!


3. Can you help me fix my game?

Maybe. There are some common easy-to-fix problems that affect all video games. Socketed chips, connectors, power supplies and monitors seem to encompass the majority of problems. Most often, I get mail from someone whose game worked fine one day, then didn't work the next time they turned it on. In many cases, there is an easy solution, but you have to do a little detective work. Video games can be generally broken down to 4 main active parts: the monitor, the game board, the control panel and the power supply. You need to figure out which part isn't working correctly. The monitor may be dark because the game board is dead, the power supply is dead or the monitor itself is dead. If you can put a quarter in the machine, hit start and hear the game playing, you probably don't need to check the power supply.

Developing a talent for determining which part of a game is broken saves a lot of time spent in hit-and-miss diagnosis. There are many hints the game provides, but you have to learn how to read them. If nothing happens when you plug in and turn on the game, there's probably a major power supply problem, such as a tripped breaker or blown fuse. If the monitor has no picture, you need to listen for the high-pitched whine from the CRT. If you don't hear it, the monitor probably doesn't have high voltage.

Here's a link to a Williams repair page: Williams Repair Log

My first shot at any repair is to remove and replace all connectors. This tends to clean the pins and make better connections. If I suspect a socketed chip, I'll carefully remove it and replace it. The repeated heating/cooling cycles of game play can cause 'chip creep', where an IC works its way out of its socket.

There are some extremely common problems with Williams games. Usually, the game won't start at all. It can still give you some info on what the problem is, though. Inside the cabinet on the ROM board is a red LED that usually displays '0' when the game is playing normally (although Sinistar displays a 'c'). When there's a problem, this LED flashes a code that indicates the problem. 1-X-Y shows a RAM error in bank X (1-3), chip Y (1-8). 2-X-Y shows a ROM error in ROM chip XY (01-12). 3 shows a CMOS RAM error. Sinistar also has a 4 code that means one of the SRAMs on the ROM board is bad. Defender has 4 single LEDs instead. If these LEDs blink twice on reset, everything's OK. If not, check here: Defender Manuals

If you get a RAM error, try swapping the indicated chip with one of the other RAM chips. If the error code changes, you have most likely found the bad chip. Note that a RAM error doesn't necessarily mean that a RAM chip is bad, especially if the error message is 1-3-1, which is the first RAM chip tested. In this case, you might still get 1-3-1 even after swapping RAM chips. This might indicate a problem with another IC on the CPU board, a bad or dirty connector, or a power problem.

Another problem is when the game starts fine, but it resets during play. This is generally caused by a power problem. The RAM chips on these games require several different voltages, and if any of these have a problem, the game can't play. You can check voltages at the RAM chips on these pins: pin 1= -5v, pin 8= +12v, pin 9= +5v (be careful not to short any pins!) Many times, the connectors that plug onto the power supply board overheat and no longer conduct electricity well. Occasionally, the voltage drops below what the game requires, and it resets. Look for a brown or black burned section on one of the white connectors. You can buy new connectors from Jameco. I had power problems on my Joust machine that caused it to reset during play. I didn't have any luck fixing the existing power supply, so I bought a cheap switching p/s from Jameco and wired it in. The old supply still powers the lamps, but the new one runs all the electronics.

High score problems can be caused by bad batteries or battery holder. Turn the power off and check the voltage at the SRAM, the 18-pin IC labeled 5114 or 6514 that's one row of ICs away from the big 6809 CPU. Pin 18 should be approximately 4.5 volts. There is a diode that keeps 5 volts from the CPU board from going to the batteries, and another that keeps the batteries from powering all the chips on the board. If your batteries drain quickly, this second diode might be bad. With the power off, check +5 at another IC. If there is any voltage at all, the diode is bad. These diodes are next to the batteries. The first one (a 1N4001) is adjacent to them, the second one (a 1N5817) is right next to the first. A common problem is that people forget about the batteries and they corrode, damaging the CPU board. I hacked in an SRAM that has its own built-in battery and is rated for 20 years. Another answer is to buy a battery holder from Jameco so you can mount the batteries off the board. Many people ask me about the memory interlock switch. This is a simple switch in the coin door that is used to write-protect the first part of CMOS RAM. I guess the idea is that if someone can get into setup mode, they can't change settings without the coin door being open. All the games will run fine with this switch disconnected.


To effectively work on games, you need some tools. There are the obvious screwdrivers and wrenches, but a few electronic tools are very helpful as well. The most useful is the multimeter. This device will let you measure voltages and check resistors, fuses and connectors. You can get them from electronics stores, even Radio Shack, for $15 and up.

A logic probe is a simple device that has 3 LEDs that tell you if an electronic circuit is in the high, low, or pulsing state. You can measure high and low with a DVM, but the logic probe makes it even easier, and shows you changing signals. Under $20.

An oscilloscope gives you a display of waveforms, but it is quite a bit more expensive and more difficult to use.

You certainly need a soldering iron and solder made for electronics, not pipes. This means a low wattage iron (15 to 30 watts) and rosin core solder (no acid core, please!) Radio Shack sells a 15W grounded iron that works well. I also have their desoldering iron for pulling capacitors when installing a cap kit, or replacing chips.

You may want to invest in an EPROM reader/burner and an eraser. If you are interested in hacking games or want to build a multigame, these are a must.

I love my hot glue gun. It can be used for so many things: tacking wires down, holding ICs to be soldered in place and holding PC boards in place. The best part is that you can easily remove the glue if you need to (just be careful on painted surfaces, and I have pulled a resistor off a PC board with hot glue before).

I also use my Dremel tool all the time. I've got the battery-powered hand-held version. It comes with drill bits and cutting discs that are very handy. Have trouble removing a stripped phillips head screw or one of those security Torx screws? Just cut a groove in the head and use a flat blade to remove it.


I like to have some spare parts on hand. Most electronic parts in old video arcade games are available from electronic stores like Jameco and JDR. I keep spare CPUs, RAM chips, and several common ICs just in case. I also have a cap kit or two handy. The electrolytic capacitors in monitors tend to dry out with age, changing their characteristics. A cap kit is a set of replacement capacitors for a certain model of monitor. It takes about a half-hour to tear apart a monitor and replace the caps, and boy, is it worth it! You do have to short the CRT's anode to remove the high voltage, which is kind of exciting, but it's not too hard to do. Zanen is one company that sells cap kits for the most common monitors.


It is usually difficult to figure out what's wrong with a board if you don't have the schematics. This is a set of drawings that show how the parts on the board interconnect. So if your 2-player start button doesn't work but you checked the switch and it is OK, then you look at the schematics and see what the switch connects to. There are a few collections of digitized schematics on the 'net. Here's a good one; look under the menu item Williams/Manuals.

There's also a lot of useful information in the Wiretap archives. Great repair and troubleshooting files, pinouts of boards, how-to guides, etc:

Mike's Arcade Wiretap Archive

Always give the guys on the newsgroup a try. There are so many knowledgeable folks there who are more than happy to help out a fellow collector. When you ask for help, be sure and give enough information. A lot of people just say "My game's not working" and don't get an answer.


There are several safety rules to keep in mind, both for your sake and the game's. Respect electricity. The game board itself probably uses low-voltage DC, but the power supply and monitor can kill you. This is especially true if you are working bare-footed in the garage, when you are probably grounded very well. Read as many repair books and articles as you can, and ask on the newsgroup before you try anything new. You can cut yourself on many parts inside the game, and burn yourself on voltage regulators and soldering irons. If you break a CRT, you could possibly be injured by flying glass. Try to work in a neat area with lots of room (yeah, right!) Don't cut off the ground plug on games- if there's a wiring problem, it could save your life.

Remember to turn off the game before removing or replacing any ICs or connectors. I like to ground myself before touching boards to reduce the chance of static electricity frying anything. Always note the direction of all connectors and ICs when you remove them. It's probably a good idea to jot some notes down or draw a picture, especially if it's going to be a few days before you replace them. Be careful not to bend any pins or offset an IC or connector by one or more pins. Try not to flex any printed circuit boards, since you can break traces and cause weird problems. When pulling ICs, use a small flat blade screwdriver and work it carefully under the chip. Make sure you are not going under the socket, and be sure not to scratch the board, which can cut traces.

By the way, if you have lines at the top of the screen that flash different colors during game play, nothing is broken. That's an artifact of the hardware. The best you can do is adjust the monitor controls and/or the bezel in front of the screen to hide them. Here's some more info.


4. Will you sell me a multigame?

Nope. It's simply too much work to be worth selling. Most of the info you need is on my page, and I'm happy to help with the details. As I get more time, I'll work on simplifying the multiple hacks into a single board. If anyone is interested in working on a kit to sell, please contact me.