Konami GX

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Konami GX
Manufacturer Konami
Year 1994
CPU 68EC020 @ 24MHz
Sound 68000 @ 16MHz
Resolution 15k
Wiring Standard JAMMA
Predecessor Konami Polygonet
Successor Konami GV

The Konami GX is a JAMMA main board introduced by Konami in 1994. The system is capable of some rather impressive graphical effects (for the time) using upgrades. The system is of note for running 4 of Konami's shooters.

Type 1 Motherboard
Type 2 Motherboard

The main PCB comes in two configurations, the older Type 1 PCB, which is larger, and runs slightly warmer, and the Type 2 PCB, which is smaller and has one less Konami specific chip (Two chips were replaced with one integrated package).

Sub PCBs (which hold game roms and additional hardware) come in 4 types, which are simply named Type 1, Type 2, Type 3 and Type 4. PCBs other than Type 2 may require a different kind of Main PCB, but Type 2 PCBs, which all of Konami's shooters run on, are fully interchangeable between boards.


English Name Japanese Name Year Sub Board ROM Id
Daisu-Kiss 1996 2 535
Dragoon Might 1995 2 417
Fantastic Journey Gokujyou Parodius 1994 2 321
Konami's Open Golf Championship Golfing Greats 2 1994 1 218
Lethal Enforcers 2 : Gun Fighters Lethal Enforcers II: The Western 1994 2 312
Racin' Force 1994 1 250
Run And Gun 2 Slam Dunk 2 1996 4 505
Rushing Heroes 1997 4 605
Salamander 2 1996 2 521
Sexy Parodius 1996 2 533
Soccer Superstars 1994 3 427
Taisen Puzzle-dama 1994 2 315
Tokimeki Memorial Taisen Puzzle-Dama 1995 2 515
Tokkae Puzzle-dama 1996 2 ?
Twin Bee Yahhoo! 1995 2 424
Versus Net Soccer 1996 4 627

Problems and Solutions, Questions and Answers

  • I get a "EEPROM Error" or a black screen (Twinbee Yahoo only) and the machine won't boot. What do I do?

Hold the Test switch down while applying power to the machine. You *CAN NOT* hold this switch and wait for the machine to try to restart, you MUST be holding the switch while the machine is first powered on.

  • I just switched games and I get a black screen?

Hold the Test switch down while applying power to the machine. Same error as a bad EEPROM.

  • My board seems to get really hot in places. Is that normal?

Yes, however, Type 2 PCBs heat up less than Type 1 PCBs, but both are fine.

  • I have a faulty board, but not sure if it's the sub board or mother board.

Powering up without the sub board should give you a scrolling warning that the sub board is not attached.

  • I'm playing Run and Gun 2, Rushing Heroes, Golfing Greats 2, Racin' Force, Soccer Superstars or Vs. Net Soccer and I don't get any Video output!

Make sure you have the small filter PCB connected to the JAMMA connector on the GX Main PCB. Then, Check that you have the small 6 pin link cable connected to the "Main PCB Video Output" connector on the Sub PCB. On GX boards other than Type 2, The Sub PCB handles all rendering.

  • I'm playing Run and Gun 2, Rushing Heroes, Golfing Greats 2, Racin' Force, Soccer Superstars or Vs. Net Soccer and my Video shorted out!

Your 6 pin video link cable may be dry-rotted. try wiggling it a little bit, or, build a replacement. The connectors are JST-NH like all the connectors used on the Konami GX.

  • I installed a Type 1, 3 or 4 game in my cabinet and I get some error about checking my dip switch settings!

Your 6 pin video link cable and the Konami GX Connector PCB (GX427) Is missing. Either replace the Filter PCB or run your monitor directly up to the board.

  • My machine is JAMMA wired for a 1 slot MVS, when someone is playing on the 2p side, sometimes we hear a coin sound. What gives?

Older Konami GX games use the 2p b4 connector on the Jamma harness for Service Credit for Player 3 (Gokujyou Parodius does). Newer games do not (Sexy Parodius does not) Disconnect Button 4.

  • Wait? Player 3?

Some Konami GX games support the linking of two cabinets for 4 player support. the long white connectors at the bottom of the board on the Type 1 Motherboard, and the ones on the side on the Type 2 Motherboard are used to connect players 3 and 4 to the machine. Alternate video output is provided by the Sub PCB.

  • So what are those little white connectors for?

The pair near the P3 and P4 player connectors are for light guns, as used in Lethal Enforcers II: Gunfighters. The 4 pin one near the top of the PCB is for stereo sound output. The 3 pin one near the top of the PCB on the Type 1 Mainboard is also for Stereo Output, but provides a standard headphones type output. The Type 2 Motherboard has the solder pads for this connector, but it is not installed

  • Stereo? Cool!

Yeah, just don't connect both a mono speaker on JAMMA and a stereo speaker on the stereo connectors, or connect a pair of stereo speakers to both connectors on the Type 1 Motherboard. Every manual warns not to do this somewhere on the order of 90 times. There's probably a good reason for that. Don't forget to turn Switch 1 off once you've wired stereo speakers to get stereo sound. The Konami GX will by default output Mono sound (over both channels) through the stereo connector. Be aware that the Konami GX has an onboard amplifier, and if your cab has a stereo amplifier, you should adjust your audio levels REALLY low on the cab the first time you boot as to not blow your speakers out. For optimal audio quality adjust the Sound Volume in the operators menu to a low number (New Astro amp is more than loud enough at "1") and adjust the volume control on your amp. Doing it this way will allow clear audio even on the bass heavy sounds in some GX games.

  • I want to wire the kick for Dragoon Might, but I'm not sure how!

You need to wire the 6 buttons (and the ground, of course) to the Player 3 Button connector. Both P1 and P2 kick controls are tied to the Player 3 connector. See Konami Wiring for more information.

  • I'm running a Dual cabinet game, and I'm not getting any video output on the 2nd monitor from boot up. Is that normal?

No. For sanity reasons, Konami GX outputs the Power Up Self Test across both monitors, and only switches the output of the 2nd display once the game has started.

Changing Games

Although the Konami GX is technically capable of changing games, its less than easy. Consider buying an inexpensive Konami GX game on the internet to salvage a motherboard instead of constant switching of games. If you only plan on switching games every once in a while, this shouldn't be a problem.

Warning: You can in some circumstances physically connect two Sub PCBs to a single Type 1 motherboard. Do not do this. Make sure that only one Sub PCB is connected at one time.

First, disconnect all cables from the motherboard, including JAMMA, Stereo audio, Gun Controls, Analog controls, and the player 3 and 4 connectors. If you are removing a Sub PCB other than Type 2, disconnect the Filter Board and the 6 pin Video link cable at this time. If you are disconnecting Versus Net Soccer, Soccer Superstars, Rushing Heroes or Run and Gun 2, disconnect the 2nd monitor video cable at this time.

The second step is to remove the current game from the motherboard, to do this first we need to remove any screw mounts from the Sub PCB. Konami has helpfully put all of these mounts along the sides and in the corners, there are none in the middle, however, make sure you check the area near the amplifier in the corner left of the JAMMA connector if you are using a Type 1, 3 or 4 motherboard.

Once you have completed this step, get a pair of needle nose pliers and disengage the two small plastic tabs near the center of the motherboard, there are two, one on each side. These are at the corners of the Type 2 Sub PCB, and in the middle of the others.

The fourth and final step in removing a game is exactly that, removing the game. Very carefully and evenly, lift the Sub PCB straight off the motherboard. Do not rock the board free as the connectors are very fragile and will not likely survive the abuse. Once you have lifted the old Sub PCB free, store it in a safe place.

Once the old Sub PCB is safely stored away, connect the new Main PCB to the correct side of the motherboard. Older games may only mount one way, and to only one kind of motherboard. However, some newer games on Type 3 and Type 4 Sub PCBs come with connectors that match both orientations and motherboards. If you have a Type 1 motherboard, which is more common, the correct orientation will depend on the type of Sub PCB that you have. Big Huge Super Gigantic Read This Seriously Warning: The Type 3 and Type 4 Sub PCBs have mounts for the TOP AND BOTTOM orientations. On the Type 2 Motherboard, this isn't a problem, they only fit one way. On the Type 1 motherboard, the Sub PCB Will mount in both directions but will not work, and may be damaged, if mounted to the top! There is a 5th connector on the larger 3d enabled Sub PCBs, and it probably needs to be connected to work. It could be suggested that one should not try it. On the Type 2, this connector is available on the top of the motherboard, on the Type 1 however, there is a hole and nothing stopping you from mounting the Sub PCB incorrectly! If you have a Type 2 Motherboard, all your games mount to the top, there are no connectors on the bottom (however, Solder pads for the connectors in question exist. If you feel like building out a type 2 Motherboard to accept bottom mount Sub PCBs, go ahead.)

If you have a Type 2 Sub PCB, it mounts to the top of the system, Period. All other types should mount to the bottom of the system on a Type 1 Motherboard, as they need the middle connector which is not present on the top of the Type 1 motherboard. Once you have determined the orientation, place the Sub PCB on top of the correct connectors, and align the plastic standoffs to the correct mounting holes, then, gently but firmly press the board into place evenly.

The next step is to secure the board into place using the mounting screws removed earlier. If you removed a Type 1, 3 or 4 Sub PCB for a Type 2 Sub PCB, remove the brass standoffs from the front end of the motherboard and replace them with screws. Store any spare screws and standoffs for use later.

Next, reconnect the filter board (if necessary) and all cables. Don't forget the 6 pin video cable if you are using the filter board because without it, you will see no video output. Connect the Extra player harnesses, Gun cables, Stereo cable, and 2nd video output. The last step is to reconnect the JAMMA harness.

Now, Hold the test switch (either the on on the mainboard, or if you have a Type 2 Motherboard and a Type 1, 3 or 4 Sub PCB, the one on the JAMMA harness, as you will not be able to reach the test switch on the motherboard in this case) and turn the machine on. You will see "Checking Eeprom" on screen, you may now release the test switch. After a few seconds the screen will change to "Eeprom Initialize Complete" the system will reboot and the game will start. You are done!

4 Player Linked Cabinets Setup

First things first, You are going to need a 4 Player game, a Pile of Cables that are becoming harder and harder to obtain (but are REALLY easy to make!) and a Cabinet connector that Konami called the "Connector PCB" Which comes in two models.

  • Large: PWB400464 GU427 Connector PCB Large
  • Small: Help! Never seen one! Just heard about it!

Warning: The connector PCB does NOT use ANY power. If your second cabinet uses a Power Supply that might blow up in this case, you should consider disconnecting it!

You need to set your dip switches properly for this setup to work. One of the trade offs of a linked cabinet setup on the Konami GX is that you lose Stereo sound, as the Right channel is used for the 2nd cabinet, and the Left channel is used for the 1st cabinet (outputted over the JAMMA connector.) So first, Set the board to Mono sound (Switch 1-1 OFF) and the Board to Dual Video output (Switch 4 ON) and then of course, set switches 2 and 3 according to how your monitors suck or not.

Next you need to build the link cables. The Konami Wiring has a lot of good info on that, but if you're feeling lazy, just get 2x 4 pin JST-NH connectors, 2x 6 pin JST-NH connectors and 4x 15 pin JST-NH connectors, and simply create 4 bundles of wire that are 1:1 connections to each other and are of proper length. If you read the article however, you can find out what pins you can skip, and save some time/money/wire/crimp pins.

After that, its a pretty straight forward process of connecting the 2nd Video out on the Sub PCB to the Video connector on the Connector PCB (Both are 6 pin connectors), The 4 pin cable to the Stereo Out connector and the Audio In connector on the Connector PCB, and the 3 and 4 Player connectors up to the motherboard and Connector PCB. Turn the whole mess on and you should have one game on two monitors.

Dip switch settings

Type 1 PCBs have 2 banks of dip switches soldered, but most games only use the first two switches.

  • Switch 1: Stereo/Mono
  • Switch 2: Screen 1 Flip (Vertical)
  • Switch 3: Screen 2 Flip (Vertical)
  • Switch 4: Dual screen mode switch. (Switches between 1 and 2 screens, Dual screen games only)
  • Switch 5: Unused.
  • Switch 6: Unused.
  • Switch 7: Unused.
  • Switch 8: Unused.

Part Numbers

  • Konami GX Type 1 Mother PCB - PWB354192C
  • Konami GX Type 2 Mother PCB - PWB300456A
  • Konami GX427 Connector PCB - PWB454366B
  • Konami GU427 Connector PCB Large - PWB400464
  • Konami GX Sub PCB Type 1 - standard with an add-on 53936 on the ROM board, analog inputs, and optional LAN capability (only on Racin' Force)
  • Konami GX Sub PCB Type 2 Type A - PWB454204A - totally stock, sometimes with funny protection chips on the ROM board
  • Konami GX Sub PCB Type 2 Type B - PWB454204B - totally stock, sometimes with funny protection chips on the ROM board
  • Konami GX Sub PCB Type 3 - dual monitor output and 53936 on the ROM board, external palette RAM
  • Konami GX Sub PCB Type 4 - PWB301798A - dual monitor output and 53936 on the ROM board, external palette RAM, DMA protection

External Links