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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 Mod Install Guide

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.

Board 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.

(DIAGRAM OF JUMPERS AND REGIONS)

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.

(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 random resets. Try use little solder and do it quickly. The benefit is that only 1 permanent modification is required.

(IMAGE OF MAIN RESET METHOD)

LED VA0-1 VA4

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.

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

Jumper (J1) VA0-1 VA4

J1 is only needed if using 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 VA0-1 VA4

  • Still need to find and add the CPU Halt location (VA4).
  • Still need to verify the exact operation of J1 and amend board if necessary.
  • Guide for VA2.
  • Guide for VA3.

Program Your Own

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

Seb

The original switchless mod designed for Sega Saturn but usuable for Mega Drive region modding.

D'force3000 (D4S)

Borti4938