Connecting a PC to an Arcade Cabinet
Warning: During the arcade's heyday, it was common for an original arcade cabinet to be converted into another game as one game lost its popularity and a new game took its place. This made it more difficult to find the original cabinet in its true form and many arcade cabinets are now very rare and are considered to be valuable collectors items. Because of this, you might not want to convert your existing machine to a MAME cabinet (this process is also known as MAMEing a cabinet).
However, if you've got a cabinet that's fairly new and not considered rare, or an older cabinet that's been converted many times and bares little resemblance to its original, it's perfectly acceptable to MAME it without harming your conscience. If you MAME a rare cab the RGVAC police will find you!
Most arcade cabinets are made up of the following parts:
- Wooden or Plastic Cabinet
- Monitor - Usually standard resolution (CGA)
- Controls - Joysticks, trackballs, pushbuttons
- Game Board - Commonly referred to as a Game PCB
- Wiring Harness - Connects Game Board to Controls, Monitor, & Power Supply
- Power Supply - Converts AC voltage to AC or DC voltages required by Game Board
- Marquee - The big sign up top with the game name
An easy way to create a home Emulator Arcade cabinet is to buy a used arcade machine with a working monitor and controls. The computer and its power supply will replace the Game Board in the arcade machine. In order to use your computer in an existing arcade cabinet, you have to interface the arcade controls and monitor to the PC. Arcade cabinets which conform to the JAMMA standard are easiest to convert for PC use because there are ready made products which plug right into the Jamma Harness in the cabinet.
Most arcade machines use a CGA monitor which will not accept the VGA signals commonly used by a regular PC. CGA monitors have a maximum resolution of 640x288 and input frequency of 15.7 kHz. A PC's VGA card outputs signals at a frequency of 31 kHz. Connecting a CGA monitor to a standard VGA card at 31 kHz will not work and will likely cause damage to the arcade monitor. There are two widely recognized solutions to this problem. The easiest solution is to use a special VGA card in your PC called the ArcadeVGA which is sold exclusively by ULTIMARC. This VGA card has been reprogrammed to output signals at 15.7 kHz. The second solution is to use a program called POWERSTRIP or AdvanceMAME with compatible VGA cards to force them to output at 15.7 kHz.
The second consideration in using a computer in an existing arcade cabinet is interfacing the controls with the computer. Since the joysticks, trackball, and buttons are already connected to the wiring harness, it is easiest to use an interface which will connect the wiring harness to the PC. The most popular device used to interface a JAMMA standard arcade cabinet's controls to a PC is the J-PAC. The J-PAC connects to the arcade controls via the Jamma Harness and to the PC via USB or PS2. The J-PAC also accepts the video signal from the computer's video card and sends it to the arcade monitor through the Jamma Harness.
It is still possible to connect a Non-Jamma cabinet to a PC. You can either re-wire the cabinet with a Jamma Harness and use the J-PAC or you can simply run new wires to the controls and connect them to any keyboard encoder, gamepad encoder, or keyboard hack.
