A different type of reverse engineering challenge. Over the weekend, I obtained a Japanese pachislo/pachislot (パチスロ) machine. These machines are similar in nature to US slots, but are refered to as "skill-stop" machines. They allow the player to click a button to individually stop each slot reel in attempt to get the required combination.

This machine came with no manual; I scoured the internet, but there are few places that document these machines on English google, with the exception of some very specific forums such as PachiTalk. This post serves as a spot for me to document some of the findings as I've been analyzing the machine and trying to gather information into one place. Something interesting to note, gambling is generally illegal per Article 23 of Japan's Criminal Code. Pachislot machines are the loophole as they don't use real currency, but instead tokens, like you'd see at arcades.

Model Information

The following information is based off of my machine from the various labels. From what I have gathered, many machines of a certain era / manufacturer appear to be relatively similar, with just the visual imagery changed to different themes. I'm unsure of how universal the below is across all machines.

This particular model has the lucky 777 branding all over it. It is the prized combination for the slots and bonus modes. This machine details an ANT (Assist Navigation Time) mode for high payouts.

  • Mfr: Daido Co. Ltd (株式会社ダイド—)
  • Patent: SANKYO
  • Mfr Date: 2001 / 03
  • Model: Hanafuda (ハナフダ)
  • Frame Model: P112
  • Management Number: D101-1
  • Type: 4th Generation Pachislot (パチスロ4号機)

Patent

Patent #JP4854865B2 that I found was pretty helpful in identifying some of the boards/switches. I use PT# to reference the above marking from the patent in sections below.

Exterior Overview

Pictured is an SVG that I recreated of the exterior of my machine. I chose SVG as it's scalable, lightweight, and makes it easier to reference the specific components of the machine. I created a shortcode with the prefix EXT for use in referencing the specific elements elsewhere in this article.

  1. EXT-1 Bonus Slots
    • These light up if in a bonus mode or ANT mode. The ideal item to have here is "shichi" 七, or 7, lining up with the machine's 777 themes.
  2. EXT-2 Winning Combinations
    • This section shows all the combinations to get and the payouts. Most payouts are only 10 or 15 tokens. A special butterfly symbol can be collected 3x to trigger a REPLAY round, which does not use a token.
  3. EXT-3 ANT (Assist) Mode Combinations
    • Symbols that lightup on the left and right. Matching the lit symbol to the closest main slot wheel can guarantee triggering the bonus mode
  4. EXT-4 Main Slots
    • The three main slots, that are started by EXT-10 and stopped by the respective button in EXT-11
  5. EXT-5 Credit Display
    • Main display shows the number of tokens that are available in the pool, up to 50
    • Four symbols to the right of the display indicate various statuses. From top left to bottom right:
      • 再 Replay mode, allows a free game without spending a token PT150
      • 始 Start - Lever is ready to pull to begin game PT170
      • 待 Wait - Machine enters a waiting state and requires reset via the key (have not personally triggered this yet)
      • 投入 Insert Tokens - flashes to indicate more tokens can be added to bank / start game
  6. EXT-6 Game Score
    • Main display to show tokens from bonus rounds
    • Three symbols to the right indicate the number of tokens bet for this round:
      • 壱 1 token PT210
      • 弐 2 tokens PT220a
      • 参 3 tokens PT230a
    • Generally, you should always use 3 tokens per round for the chance to enter ANT or get a Big Bonus
  7. EXT-7 Payout Display
    • Display which indicates the number of tokens won this round. If the credit display (EXT-5) is less than 50, these tokens can be added directly to the banked credits.
  8. EXT-8 Cashout Button PT450
    • Button immediately dispenses all tokens listed under Credits EXT-5 and/or Winnings EXT-7
  9. EXT-9 Credit Selection Buttons
    • Buttons to select either 1 token or 3 tokens (MAX) from banked credits for this round
  10. EXT-10 Start Game Lever
    • Pull lever to start the slots
  11. EXT-11 Slot Stop Buttons
    • Button to slot each respective slot wheel
  12. EXT-12 Token Entry Slot
    • Insert tokens here for play
  13. EXT-13 Identification Label
    • Manufacturing label which shows varying information such as model, serial number and more
  14. EXT-14 Authenticity Label
    • Label which shows patent holder and manufacturer
  15. EXT-15 Token Collection Tray
    • Tray for holding excess tokens / cashed winnings

Interior

Power Supply

On the interior, there are several boards that control various functions of the system. From what I can tell, many of these components are shared in all machines to control the "brains". The power supply is unique (to me) as it contains several switches for additional functions. Any references to this chart will have the PWR- prefix.

  1. PWR-1 設定キー Settings Key PT622
    • Either requires a physical key or is a toggle switch
    • This being set to ON will allow configuration, such as changing payout rates.
    • In my testing, it requires a specific sequence of steps to properly activate.
  2. PWR-2 精算 Settlement Switch
    • Have not seen a diference in changing this. Per the Pachislo Slot Machine Operation Manual, "On most machines, there will be two slider type switches on the power supply that are labeled with Japanese writing. These were for use in the Japanese casino and have been disabled. These were used to notify casino personnel that the machine was either out of coins or the overflow tray was full. The position of these switches will not affect the operation of your machine"
    • The patent describes that the switch detects the operation of EXT-8. Perhaps toggling this off means this button ceases to work?
  3. PWR-3 打止め Stop Toggle
    • See above. I assume it has something to do with the stopping the machine after a certain amount of bonuses for topping up overflow.
  4. PWR-4 リセット Reset
    • Appears to be for resetting machine to factory settings
  5. PWR-5 設定 Settings Button
    • used to set payout level
  6. PWR-6 設定 Main Power PT624
    • activates power to the machine

Inner Workings

Various parts I've identified

  • Bulbs
    • #400 28v 3w Wedge Base Light bulb for the various lights
      • Also appears #2841 24v 3w Wedge bulb can be used
      • 10mm diameter, 2.1mm wedge base depth, 9.5mm wedge base width

  • Boards

    • SG011D/SG011E - Stop Reel Board (I have SG011E, which looks identical to SG011D. Assuming it’s the same board)
      • G1CN1 - 30 pin plug to T2CN2 on 112T012C
    • SP021B - Power Supply PT102
      • P1CN3 - 18 pin plug to S1CN1 on 11206A1C
    • SA021E - ??? Board
      • A1CN1 - 26 pin plug to S1CN2 on 11206A1C
    • 11206A1C - Main Board PT100
      • S1CN1 - 18 pin plug to P1CN3 on SP021B
      • S1CN2 - 26 pin plug to A1CN1 on SAO21E
      • S1CN3 - 40 pin plug to T2CN1 on 112T012C
      • S1CN4 - 50 pin plug to T3CN9 on 112T013B
    • 112T013B - LCD Display Board
      • T3CN9 - 50 pin plug to S1CN4 on 11206A1C
    • 112T012C - Reel Relay Board PT103a
      • T2CN1 - 40 pin plug to S1CN3 on 11206A1C
      • T2CN2 - 30 pin plug to G1CN1 on SG011E
      • T2CN6 - 2 pin to Hopper Full Sensor PT611
    • 112T014B
      • T4CN1 - 4 pin to Left SL011B
      • T4CN2 - 4 pin to Middle SL011B
      • T4CN2 - 4 pin to Right SL011B
    • 3x SL011B - Reel Lamp Relay Boards PT103B