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COVID-19 UPDATE: Shipping is affected by the UK lockdown starting 23rd March 2020. I am still shipping worldwide but will no longer go to the post office. All mod kits will be posted as standard large letter. Install service returns are posted via tracked & signed courier. Many thanks

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

Mod Pinout

Solder Map

  • 5V – Solder to side of R12 or scrape away solder mask of the flat area it is attached to.
  • GND – Solder to C8 pad or side of C49 or C51 or scrape away solder mask of the flat area it is attached to.
  • VID – Controls 50/60hz switching. Solder to exposed trace after scraping away solder mask.
  • LAN – Controls JPN/ENG language.  Solder to exposed trace after scraping away solder mask.
  • RL – Reset line. Solder to exposed trace after scraping away solder mask.
  • RB – Reset button. Solder to solder pad.
  • L1 – Solder to the long Outer lead of the LED.
  • L2 – Solder to the short Outer lead of the LED.
  • COM – Solder Middle leg of the LED into the Left hole (ground) where the original LED was.
  • C9 – Solder to pin 9 of controller port 1 (underside).
  • C6 – Solder to pin 6 of controller port 1 (underside).
  • CPU – Pauses the game during region change. Solder to PIN 19 of the Mega Drive 2 CPU.

Reset Line, Video & Language

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.

Scraping the Traces

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 you to achieve a better soldered connection. Once scraped the trace should be shiny which will show that you have removed the necessary amount of solder mask.

Soldering to the Pins

Alternatively you can 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. You have the options of lifting the pins from the board and soldering to them, in which case you will not be required to cut the traces. Or leave the pins connected to the board and solder to them, in which case the traces will need cutting.

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.

Controller C6 & C9

  • 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.

(IMAGE OF WIRE THREADED THROUGH CONNECTOR)

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.

(IMAGE OF ALT SOLDER POINTS)

CPU Halt

  • MD2 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.

Jumpers (J1)

J1 is only needed if you use a Mega CD with a MultiBIOS. When not set, the outputs CD1 and CD2 will change when the console is changing region. When set, these outputs are only changed after a reset. This prevents the MegaCD MultiBIOS from changing during operation which can sometimes cause the BIOS to crash.

LED

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 your LED through this second type there is a great risk that you can lift the pad on the underside and tear it off. You need to be careful when threading the LED.

The middle leg of the LED will secure the LED to the Mega Drive mainboard. The two outer legs will need bending at right angles and wiring to the L1 and L2 pads.

Diffuser

Depending how you made the leg bends, 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.

Power and AV Socket Fix

Whilst you have your console 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 it flows and becomes whole again.

Sega Mega Drive 2 VA4

Video & Language

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.

(DIAGRAM OF JUMPERS AND REGIONS)

Controller C9 & C6

  • 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.

(IMAGE OF CONTROLLER PINS)

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.

(IMAGE OF WIRE THREADED THROUGH CONNECTOR)

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.

(IMAGE OF ALT SOLDER POINTS)

Reset

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.

(IMAGE OF ALTERNATIVE RESET METHOD)

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 glitching and random resets. Try use little solder and do it quickly. The benefit is that only 1 permanent modification is required. This is my preferred method and why I included this in the main solder map image.

(IMAGE OF MAIN RESET METHOD)

LED

The LED will need soldering into the original ground hole. For this reason a common cathode LED is best. The LED 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.

(IMAGE OF BENT LED)

Orient the LED so the legs point towards the right side of the board. This will make your wire runs neater than orienting it so the legs point towards the back of the board.

(IMAGE OF LED ORIENTATION)

Jumper (J1)

J1 is only needed if you use a Mega CD with a MultiBIOS. When not set, the outputs CD1 and CD2 will change when the console is changing region. When set, these outputs are only changed after a reset. This prevents the MegaCD MultiBIOS from changing during operation which can sometimes cause the BIOS to crash. (Still needs varifying)

Notes

  • Still need to find and add the CPU Halt location.
  • Still need to verify the exact operation of J1 and amend board if necessary.
  • Guide for VA2.
  • Guide for VA3.