User DogP of Sega-16 forums posted in a technical thread the process on how to restore Sega Master System support on a 32X. Essentially, this allows A21-A23 to act normally when in Genesis and 32X mode, but drive A21-A23 when in SMS mode. This circuit controls the direction by using the /M3 signal (pin B30) to pass the 32X signals when high.
 | This mod's compatibility is limited to Genesis Model 2 systems and was found to be inconsistent across multiple boards of the same revision in DogP's original thread. Model 1 systems do not work with this mod. It is speculated that the main 32x gate array and address selector (315-5818 and 315-5805) are much less lenient on bus timings, resulting in the inconsistency. Work RAM and VRAM are also suspected to be problematic in this regard. See the compatibility section on this page. |
Materials Needed
- A 74ACT241 chip
- Kapton or masking tape
- Double sided tape
Installation
- Connect the 74ACT241 as shown below.
- Put a piece of kapton or masking tape across the pins so that only a small bit is exposed to prevent solder from traveling down the pin. Solder a wire to pins A21, A22, and A23.
- Cut these three traces connected to the cart socket, or alternatively put kapton tape over pins 8/9/10 of the ribbon cable as shown below.
- Attach the 74ACT241 chip somewhere securely with double-sided tape, such as in this location under a ribbon cable.
- Solder wires to the 32X A21-A23 output (CN1 pins B11-B13), and +5V/GND (left side of capacitor is +5V, right side is GND).
- Route the wires to avoid getting in the way of reassembly. Solder the wires to the chip according to this diagram.
- Reassemble and test.
Compatibility
The following games do not work with this mod. The original list was compiled by MicroNut99.
| Game Name | Notes |
|---|---|
| Addams Family, The (Europe) | |
| Aladdin (Europe) | |
| American Pro Football (Europe) | |
| Battle Out Run (Europe) | |
| Cosmic Spacehead (Europe) (En,Fr,De,Es) | |
| Desert Strike (Europe) (En,Fr,De,Es) | |
| Dinobasher Starring Bignose the Caveman (Europe) (Proto) | |
| Earthworm Jim (Brazil) | |
| Fantasy Zone II - The Tears of Opa-Opa (Japan) | |
| Fantasy Zone II - The Tears of Opa-Opa (USA, Europe) | |
| Fire & Forget II (Europe) | |
| Gauntlet (Europe) | |
| James Bond 007 - The Duel (Brazil) | |
| James Bond 007 - The Duel (Europe) | |
| Jurassic Park (Europe) | |
| Kenseiden (Japan) | |
| Kenseiden (USA, Europe) | |
| Line of Fire (Europe) | |
| Loretta no Shouzou (Japan) | |
| Lucky Dime Caper Starring Donald Duck, The (Europe) (Beta) | |
| Lucky Dime Caper Starring Donald Duck, The (Europe) | |
| Masters of Combat (Europe) | |
| Micro Machines (Europe) | |
| Out Run (USA, Europe) | |
| Out Run 3-D (Europe) | |
| Pit Fighter (Brazil) | |
| Pit Fighter (Europe) | |
| Populous (Europe) | |
| Road Rash (Europe) | |
| RoboCop 3 (Europe) | |
| RoboCop versus The Terminator (Europe) | |
| Scramble Spirits (Europe) | |
| Simpsons, The - Bart vs. The World (Europe) | |
| Sonic The Hedgehog (USA, Europe) | |
| Sonic's Edusoft (Proto) | |
| Summer Games (Europe) (Beta) | |
| Summer Games (Europe) | |
| Super Smash T.V. (Europe) | |
| Super Space Invaders (Europe) | |
| Super Tennis (USA, Europe) | |
| Super Wonder Boy - Monster World (Japan) | |
| Taz-Mania (Europe) (Beta) | |
| Tecmo World Cup '92 (Europe) (Beta) | |
| Tecmo World Cup '93 (Europe) | |
| Teddy Boy Blues (Japan) (Proto) (Ep-MyCard) | |
| Terminator, The (Brazil) | |
| Terminator, The (Europe) | |
| Thunder Blade (Japan) | |
| World Grand Prix (Europe) | |
| World Grand Prix (USA) | |
| WWF Wrestlemania - Steel Cage Challenge (Europe) | |
| Zaxxon 3-D (World) (Beta) | |
| Zaxxon 3-D (World) | |
| Zillion (Japan, Europe) (En,Ja) | |
| Zool - Ninja of the 'Nth' Dimension (Japan, Europe) |