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Sega Mega Drive Model 2 Switchless Region & In-Game-Reset Mod Install Guide

This install guide will show how to install the custom switchless region and in-game-reset mod kit into a Sega Mega Drive model 2 games console. The guide covers model 2 revisions VA0, VA1 and VA4.

Mod Pinout

Solder Map VA0-1

Reset Line, Video & Language VA0-1

There are no pads of jumpers on the Mega Drive 2 VA0-VA1 for these connections which makes this install more difficult than an MD1 region mod. The Reset Line, Video, and Language connections need to be made to either the traces or the IC pins.

Cutting Traces and Solder Mask Removal

The best way to do this is to use the tip of a scalpel whilst viewed under magnification. It is best to scrape the solder mask from the trace along the length of the blue line in the image. This will reveal a greater area of copper that will allow a better soldered connection. The trace should be shiny which will show that the correct amount of solder mask has been removed.

Soldering to the Pins

Alternatively leave the traces unscraped and instead solder to the chip pins. Pins 46, 78 and 107. This method will require 30awg solid core Kynar wire and there is greater potential for damage. This is much more difficult and requires very fine soldering skills as it is easy to bridge the pins of the IC. There are two options.

  1. Lift the pins from the board and solder to them. Do not cut the three traces.
  2. Leave the pins connected to the board and solder to them. Cut the three traces.

Lifting pins will mean there is no permanent alteration to the Mega Drive 2 so might be the preferred method for purists, but the risk of breaking the pins is high.

CPU Halt VA0-1

  • CPU Pin 19

When this is connected the game will pause when START+A+B+C is held long enough to start cycling through the console’s regions. Only connect this if you want the game to pause when
cycling through the regions.

Solder Map VA4

Video & Language VA4

Video and language are hard set on the VA4 by two zero ohm resistors soldered across some jumpers. On the PAL board the jumper for Video will be connected to Ground and the jumper for Language will be connected to +5V. By removing these zero ohm resistors we can control the video and language, which determine the region of the console, with the modchip.


Reset VA4

In order for reset to be controlled by the modchip a trace cut is necessary. There are two options for this and both come with their own problems and benefits.

1 - Top trace cut and solder mask scrape.

This requires that solder mask is removed from the thin trace and then a wire soldering to that exposed trace. This is sometimes more difficult than it sounds and is one extra thing that is permanently altered on the console.


2 - Bottom trace cut and soldering direct to the button leg.

This requires that a trace is cut on the bottom of the board and a wire is then soldered directly to the button leg. Soldering to the leg requires more heat and it is possible to permanently damage the button if you are not careful. Also flux can get inside the reset button which can cause random resets. Try use little solder and do it quickly. The benefit is that only 1 permanent modification is required.



There are two types of LED solder points on the model 2 Mega Drive. Some are through hole plated with a solder pad on the top and bottom layers. The other type is not through plated and only has a pad on the bottom of the board. When pushing the LED through this second type there is a great risk that the pad on the underside can lift and tear off. Be careful when threading the LED.

The LED will need soldering into the original ground hole on the Mega Drive mainboard labelled COM. For this reason a common cathode LED is used for Mega Drive 2 region modding. The common LED pin will need bending in a specific way in order for the common pin to line up and centralise the LED to the location of the original LED, this requires two bends. One straightening the pin outwards and a second bending the pin downwards. The two outer pins will need bending at right angles opposite to the common pin and wiring to the LED OUT pins on the modchip.

The LED or the wires will not move once in place so there is no need to add heatshrink tube to the LED pins for strain relief.

Diffuser VA0-1 VA4

Depending how the LED pin bends were made, the new LED might not fit below the diffuser. In this case some material will need removing from the diffuser. A rotary tool is best for this task. In order to avoid this, make sure the LED pin bends are tight and flush to the LED bulb.

Controller C6 & C9 VA0-1 VA4

  • C6 to Controller Port Pin 6 which detects when A+B is pressed.
  • C9 to Controller Port Pin 9 which detects when C+Start is pressed.


To get the wires to the bottom of the board for soldering these points you can go through the controller connector case. Threading the wire from the bottom of the board to the top through the connector is the easiest method for this.


Alternative Controller Points

Alternatively you can scrape solder mask off two vias on the top of the board for soldering the wires. This requires a permanent modification to the board and is very fine soldering which some might find difficult.


Power and AV Socket Fix VA0-1 VA4

Whilst the console is open it is a good idea to check that the solder connections on the bottom of the board for the sockets are intact.

If not, apply some new solder and heat the connection until they flows and become whole again. More often than not, they are broken and need resoldering

Jumpers (J1, J2, J3, J4)

Depending on the board revision, these jumpers might not be available. The board will be hard wired to the best set-up.

J1 – Reset on region change - When set to (+) changing the region via the reset button or controller will have an instant affect on the video rate. When set to (-) changing the region via the reset button or the controller will reset the console and the new region will be set on boot up.

J2 – IGR extended mode - When set to (+) the console will reset if the controller button combination is held and then released when the LED turns off. If held longer the console will cycle through the regions. When set to (-) the console will just reset when the controller button combination is held.

J3 – Set the LED type - CA = Common Anode, CC = Common Cathode. All kits come with Common Cathode LEDs but if the LED ever needs swapping for a Common Anode LED, this jumper will need changing from CC to CA.

J4 – Routing the IGR - When set to (RL) the reset out of the IGR PIC will be connected in parallel with the Reset Line out of the Region PIC. When set to (RB) the reset out of the IGR PIC will be connected to the Reset Button input of the Region PIC. When not connected the IGR and Region PICs are disconnected from each other which will aid in troubleshooting installs. The RST pad can then be used to connect to a reset location on the Mega Drive board. The RST pad must not be used in conjunction with the J4 jumper.

Program Your Own

If you want to make this yourself you can get the codes from the following links.


The original switchless mod designed for Sega Saturn but usable for Mega Drive region modding. Only usable with active high reset Mega Drive consoles.

D'force3000 (D4S)



Still need to find and add the CPU Halt location (VA4).