Archive for the 'Arcade' Category

Everything you’d want to know about Sega Type II IR Light Guns. Part: 2 LED Boards

In Part 1 I discussed a high level overview of how the Sega/OHMIC IR light gun setup works. Here in Part 2 I’m going to start breaking down the technical details.

As stated in part 1 there are essentially 3 parts to this setup,
1. A chain of 10 or 12 Addressable IR LED boards explicitly positioned around the parameter of the display
2. IR motion sensors in the gun housings.
3. The “Gun Sense” board (essentially the Gun IO).

In this Part I’m going to discuss the LED Boards.

Pinout and Wiring

The IR LED modules have two 6-pin connectors. The connectors, one marked “IN” and one marked “OUT”, are pinned identically. The LED modules are designed to be “chained” together with the output of one module going to the input on the next. The input on the first module comes from the Gun Sense board and the output on the last module is left empty; not connected to anything. Interestingly the LED output connector on the gun sense board is pinned backwards from the connectors on the LED modules:

These use a 6-pin JST XH family connector

The function of each pin isn’t documented (the manuals simply reference the data pins as “A”, “B”, and “C”) and unless you’re reverse engineering the LED board you simply need to follow the pinning in the picture above. It’s worth noting though that the power pins follow standard Sega wire color. On the LED board connectors the pinout is as follows:

  1. GND (white)
  2. A (orange)
  3. B (green)
  4. C (blue)
  5. +5V (yellow)
  6. +12V (red)

LED Positioning Around the Monitor

Depending on the Gun Sense board, there could be 10 or 12 LEDs in a chain. In-fact Jurassic Park The Lost world was the only game that shipped with 12 LED modules and every subsequent game has used only 10. Despite this fact most of the gun sense boards actually have a dip switch to switch between the 10 and 12 LED configuration (more on this in the Gun Sense Board section).

The 12-LED configuration must be in the pattern below with “1” being the first board in the chain after the gun sense board and “12” being the end of the chain.

LEDs 4, 6, 10 and 12 are what mark the corners of the screen. Typically these corner LEDs are rotated at a 45degree angle though this is likely for wiring purposes as the angle of the LED board is irrelevant as long as the sensor in the Gun can see it.

The 10-LED configuration must be in the pattern below with “1” being the first board in the chain after the gun sense board and “10” being the end of the chain.

On the 10 LED arrangement you might notice that LEDs 4, 5, 9 and 10 are in the corners and there is no longer any LEDs on the left and right sides of the screen. In both configurations the LEDs should be evenly spaced and aligned parallel with the edge of the screen.

IR Wavelengths

One other thing you might Notice in the photo above is that you can see a faint red light in each of the LED locations. Indeed these IRs LEDs output light that dips slightly into the visible spectrum. It’s enough that in a dimly lit room on close inspection you can easily verify if your LEDs are powering on.

OHMIC supposedly used custom LEDs with a non-standard wavelength to prevent 3rd parties from making and selling replacement parts. I actually tested several of the LED boards against a Light Spectrometer to determine the output range, which you can see below.

Most games came equipped with small Tinted plastic windows that would be placed in front of the LED module. These are designed to let only IR light through so they appear to be a very dark red, almost black in color and they mostly only exist to make the arcade machine look “cleaner”. I’ve found that by NOT using these windows the range in which the guns work can be improved quite a bit.


There is not much that can go wrong with the LED boards, they’re pretty robust and the circuit is simple but the LEDs failing is usually what kills them.

Given that you can actually see some faint red light if they’re powering on you can easily tell if the LEDs are dead. Unfortunately due to the proprietary wavelength there are (at the time of this writing) no known good replacements. I do hope to change that eventually once I have some time to test various LEDs on the market and compare their output against the baseline I pulled from the original LED module. Until that happens your only real recourse is to simply replace the whole module. Thankfully replacing only one or two is generally inexpensive.

If you’re wiring up your setup for the first time and some or all of your LEDs aren’t lighting up you’ll want to first verify that it wasn’t installed backwards. Given that the input and output connectors are pinned identical there’s no risk of backwards voltage damaging the board but it also means it’s easy to accidentally install backward. Indeed I’ve done this a few times by accident and it didn’t seem to damage the LED board (at least not after a short period).

LED Board Variations

There are a number of variations of these LED boards, they all seem to be cross-compatible with each other and with any Gun Sense board, you can even mix and match them in the same chain. Though, depending on your cabinet some will work better than others in terms of gun range.

The original 2-LED module used on Jurassic Park The Lost World. Notice that the LEDs are arranged vertically and there is a glob of silicone placed below them to hold them in place. These actually work well with larger screens as you can move and adjust the LED angle to your liking.
The newer 2-LED module. Note the horizontal arrangement of the LEDs and the small plastic shroud. These were first used on House of the Dead 2 and continued to be used for most Sega IR Light Gun games through NAOMI, Hikaru, Chihiro, and Lindbergh (maybe further). These are going to be the most common LED board you come across.
This is an LED module from Namco’s Time Crisis 4, it’s nearly identical to the 2 LED Sega Model above. The most notable difference is PCB sizing is slightly different.

This is a 3rd Party Reproduction LED board that I’ve seen pop up in Europe. I find it intriguing that it has provisions for up to 6 LEDs though I’ve heard nothing but complaints about this PCB with guns having difficulty tracking them. Perhaps the wavelength is incorrect?
This is a 4-LED module, I’ve seen the part number referenced in the manual for Ghost Squad, however photos of actual machines show a normal 2-LED module. Having spoken to a former Sega Employee on the subject these modules were a special creation for custom large-screen installations where long-range was needed. Supposedly they made enough of them that most of them were sold as replacement modules along-side the normal 2-LED versions.

These are newer models used on Taito/Square Enix GunSlinger Stratos cabinets. Note the lack of any through-hole components. I also appreciate that each LED appears to be uniquely driven by it’s own transistor, where as on older LED boards they are typically wired in series.

There may be other LED modules in the wild but those above are the ones I know of, If you have photos of others please contact me and I will add them.

To Be Continued…
In Part 3 I will cover the IR Sensors

Everything you’d want to know about Sega Type II IR Light Guns. Part 1: Overview

In 1997 Sega released Jurassic Park The Lost World Arcade; a Light Gun Shooter on the Model 3 Arcade hardware. This was the first game to use Sega’s new IR gun technology, a system that they’ve used for nearly every light gun game they’ve produced since.

Continue reading ‘Everything you’d want to know about Sega Type II IR Light Guns. Part 1: Overview’

A Better Vewlix Power Supply

My Work-In-Progress Vewlix F

Recently I’ve been fixing up a Taito Vewlix F cabinet, this cabinet has the optional “JAMMA Kit” which includes the incredibly crappy Wei-Ya P271 Power Supply. This Power supply is notorious for pulsing the 12V line and killing itself (and potentially PCBs) when run on 120V AC.

Continue reading ‘A Better Vewlix Power Supply’

Light Output on Hyper Bishi Bashi Champ for Konami System 573

Last week I posted an article on getting light output from Salary Man Champ on Konami System 573, I suggest you read that first. Much to my chagrin the shift-register circuit I used there didn’t work with Hyper Bishi Bashi Champ. Through pictures I found online it seems that the 2 Player Hyper Bishi Bashi champ cart, while using the same light output pinout and having the same outward appearance and a very similar looking cartridge PCB actually used a very different light output circuit. Rather than a pair of shift-Registers it uses a pair of 74LS175 D-Type Flip Flops.

Here are some photos of the HBBC 2P cart (courtesy of nem on

Continue reading ‘Light Output on Hyper Bishi Bashi Champ for Konami System 573’

Light output for Salary Man Champ on Konami System 573

I’ve been playing around with a non-rhythm game version of the Konami System 573 hardware, namely I’m interested in the various “Champ” games, these are collections of manic versus mini-games where you smack buttons and hilarity ensues.  The most popular is Hyper Bishi Bashi Champ and Salary Man Champ. If you’re unfamiliar with the game each player has just 3 colored buttons (no joystick) and the buttons also light up corresponding to what’s happening in game.

Continue reading ‘Light output for Salary Man Champ on Konami System 573’

ROMIDENT Drag and Drop Tool

What is ROMIDENT and why should you care?

When troubleshooting an an arcade PCB it can sometimes be helpful to compare the ROM data on your PCB to the ROM data within MAME. MAME is more than just a way to play classic games, the documentation within the source code is invaluable to understanding how the hardware works, and the ROMs themselves can serve as a tool to compare and verify the ROMs on your original arcade hardware.

To this end MAME has a great feature called “romident”. You’ll first need to use a EPROM reader/writer to read the data off of you EPROM or mask ROM and save it to a file, then you can check to see if that file exists in MAME by running this command: Continue reading ‘ROMIDENT Drag and Drop Tool’

Sega ST-V “Titan” Metal Cage (Atlus Print Club 2 PCB)

I’m a big fan of metal cages over my Arcade PCBs. They’re the best way to protect the PCB and they help cut down on electrical interference so the game runs at it’s best. I own an ST-V (“Sega Titan-Video”) PCB (which is the arcade equivalent to a Sega Saturn) and I knew it had an optional Video board used in the “Print Club” machines. While trying to find info on that optional board I discovered that in the Print Club machines also had a cage around the whole ST-V Board setup! I found a complete setup for a reasonable price (less than that of a spare ST-V board alone, so worst case I break even) so I bought it.

A number of people have expressed interest in the size of this cage and others in seeing what the guts of this thing looks like so here’s a quick photo dump.

Continue reading ‘Sega ST-V “Titan” Metal Cage (Atlus Print Club 2 PCB)’

Building an Emulation PC for an Arcade Machine

If you have or want to build an arcade machine that displays and plays emulated games as authentically as possible then there are a number of things to consider that are quite different when compared to building a normal gaming PC. This guide assumes that you have a functioning arcade machine already and that you’re simply looking to install a PC in it to use along side your arcade PCBs.


Continue reading ‘Building an Emulation PC for an Arcade Machine’

Tour of my Game Room 2016

I’ve done a brief video tour of my Game Room for those that are interested.

If you want to know what it looked like before I got back into arcades, or a more detailed look at some of the Collectors edition console games on the shelves I have a similar video from 2012

SUN (NAOMI) Power Supply Re-Cap

The Sun brand JVS power supply units also known as “NAOMI” PSUs due them being most widely used on that platform have become quite expensive in recent years, even worse is that due to their age many are starting to fail. What most people don’t realize is that similar to CRT monitors, power supplies usually fail due to aging capacitors and many can be revived with a simple cap-kit.


Why not just buy a different PSU?
Normal Arcade power supplies only supply 5V and 12V outputs where as the JVS power supply standard requires 3.3V output as well, also there is a specific connector (JST VL) used for JVS power connections where as normal arcade supplies use either screw terminals or Molex connectors. Even if they did support 3.3V output, the output amperage specs for JVS are also higher than what most 15Watt arcade PSUs can provide, some JVS boards have power consumption requirements low enough that this would be ok but others do not.

There are some people who make ATX to JVS PSU adapters allowing you to use a standard desktop PC power supply for JVS arcade boards however PC power supplies are not adjustable and depending on the specific board you’re using and how your specific ATX supply is tuned it may be providing voltages too high or too low to function properly with a JVS arcade board.

Why Replace the Caps?
Over time the chemicals in electrolytic capacitors break down and expand causing them to not work as well as they should which can cause instability and noise in the power output, in worst cases the capacitor housing can crack and start leaking which can cause corrosion of metal parts and erosion to the PCB. I’ve seen these Sun PSUs sell  for $80-$100 in used condition on eBay, many of these are even in need of a cap kit. The very few shops that sell new JVS PSUs charge upward of $300. Meanwhile a cap kit can be purchased for about $8 and with about an hours work can make a dead or unreliable Sun PSU function like new again.

Not to mention spending some time and a little bit of money to repair instead of replace something is much better for your wallet, the environment, improving your skills, and preserving the authenticity of your arcade equipment. It’s win-win from all aspects.

The Cap List
This electrolytic cap list is for the Sun 400-5397-01  model number (the 400-5443 may or may not need the same caps, I didn’t have one available to check). The filter cap is generally very expensive compared to the rest of the list and generally only replaced on an as-needed basis.

C5 – 680uF 200V *Filter Cap
C9 – 47uF 50V
C14 – 22uF 50V
C15 – 10uF 50V
C17 – 1uF 50V
C18 – 2.2uF 50V
C19 – 4.7uF 50V
C21 – 1000uF 10V
C23 – 220uF 25VC24 – 3.3uF 50V
C25 – 330uF 16V
C28 – 2200uF 10V
C29 – 2200uF 10V
C31 – 2200uF 10V
C32 – 2200uF 10V
C34 – 4.7uF 50V
C35 – 2200uF 10V *A small diameter cap is preferred here
C36 – 2.2uF 50V
C37 – 0.47uF 50V
C38 – 3.3uF 50V
C41 – 10uF 50V

Cap Location Map
Here is a map I’ve put together of where each of these caps is located on the PCB and the direction each cap should be facing. When replacing the caps you should take note of the capacitance, voltage and orientation of the old cap to ensure that it agrees with the above cap list and the below cap map. The PCB itself should also note the capacitor number and orientation of each of these caps for further confirmation. I’ve run into other PCBs where the markings on the board didn’t agree with the direction that the old cap was installed, but in my experience the Sun PSUs have always been marked correctly on the PCB.


*The cap map was made from a photo I took of one of the PSUs I performed a cap kit on. take note of the blackened PCB by C28, this cap had already cracked and started leaking on the bottom which also caused the green/black corrosion on the neighboring resistors. Thankfully no permanent damage was done. I should also note that from the outside this PSU was running with zero problems. This was a ticking time bomb and I was lucky enough to notice the bloated and leaking cap before the PSU failed and or more serious damage occurred.

Replacing the Fan
These Sun PSUs also have an fan that can die or become very noisy. its the same size and shape as an 80mm (x25mm) desktop PC case fan. This is a 2-pin 12V fan that uses a 2-pin JST PH connector. Most PC fans wont use this connector but you can either cut off the connector of the new fan and splice on a pig-tail from the old one, or buy a JST PH connector to crimp onto the leads of your new fan.  Either way replacing this fan is another cheap way to keep your power supply running in top shape for a good many years to come.


Where to buy these parts?
You can piece together your own cap kit using parts from Mouser, Digikey or your preferred online parts vendor, most of these stores will also carry the JST-PH connector for the fan as well. 80mm cooling fans can be found anywhere computer parts are sold.

If you’re interested in buying a pre-made cap-kit instead of piecing one together yourself Ian Kellogg sells one and he also sells the filter cap. I don’t know of anyone else making kits for these PSUs at the moment but if you know of any please leave a comment.