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Sega Mega Drive Switchless Region Mod Install Guide

This is a general installation guide that covers installing a switchless region mod into a Sega Mega Drive. It can be used for any chip code and all Mega Drive board variations that might be encountered when doing this mod. This guide currently includes Mega Drive revisions NTSC-JVA1, PAL VA4 & PAL VA6. Any other board revision that has drastic variations to what is shown here will be added over time.

This mod will make the Sega Mega Drive fully region free, allow games to run in 60Hz, and display their original Japanese titles and language.

Mod Pinout

Solder Maps

If you are using a deadbug kit, i.e., seperate components, you will only need to connect what is shown in the pinout for the paticular code used.

Language & Video / Power & Ground

The language and video rate jumper settings on the mainboard are what determine the region of the Sega Mega Drive console. These jumper settings are easily overridden by cutting the connections and then supplying +5V or Grounding in varying ways.

  JP1-2 (Language) JP3-4 (Video Rate)
50Hz/EN (Europe) +5v Ground
60Hz/JP (Japan) Ground +5v
60Hz/EN (North America) +5v +5v

There are three different arrangements of jumpers in the Mega Drive. VA0 to VA4 which are horizontal and not sequential, then VA5 which is vertical and sequential from bottom to top, then there is VA6 which is vertical and sequential from top to bottom.


1 – First remove the capacitor that is connecting across the jumper if there is one.

2 – Cut the traces between the power/ground side and video/language side of the jumpers (red lines on images).

3 – Solder LAN and VID (Before 5V and GND)

4 – Solder 5V and GND.

Mk1 Mega Drive VA4 (IC BD M5 PAL VA4)
Mk1 Mega Drive VA5/VA6 (IC BD M5 PAL)

Reset Button

For the PIC chip to control the regions of the Mega Drive it needs to take the signal from the reset button and then rout it accordingly. This is done by cutting the line going from the reset button and putting the PIC chip in this path. The PIC chip will then determine how the reset button is pressed and then send out any required signal. A quick press of the reset button will mean the PIC chip will send out a normal reset as if the reset button line was not cut. If the reset button is held, the PIC chip will send out signals to change the region and language and not send out a normal reset signal.

1 – Cut the reset button trace on the underside of the motherboard (red line on images).

Mk1 Mega Drive VA4 (IC BD M5 PAL VA4)
Mk1 Mega Drive VA5/VA6 (IC BD M5 PAL)

2 – Solder RB to the reset button pin.

3 – For RL, solder will need removing from the vias before soldering (blue circles in images). Scrape away the green solder mask from the small pad to reveal the copper underneath. Solder RL to this. For best results use the tip of a scalpel and view under magnification. The area should be shiny before soldering.

Mk1 Mega Drive VA4 (IC BD M5 PAL VA4)
Mk1 Mega Drive VA5/VA6 (IC BD M5 PAL)

LED Installation

This is the most difficult part of a Mega Drive switchless mod install but it is entirely optional. Without it though, the region of the Mega Drive will be difficult to determine.

Two Types of Top Case LED Fixtures

Removable Bezel and LED

This is the easiest LED to remove because the bezel cover that is holding in the LED can be unclipped. The LED will then come straight out.

Fixed Bezel and Sealed in LED

This is more difficult because the LED will need cutting out from the underside of the top case. The metal legs of the LED will be in the way when cutting the hole. Once the hole is large enough, the LED can be removed.

Removing the Old LED

Remove the wires connecting the motherboard to the top cover. Removing from the top cover requires bending the metal legs of the LED up and then pulling the plastic connector off. The connection to the motherboard will require desoldering.

Cutting the Hole

Side cutters, a hand drill or an electrical rotary tool can be used to cut the hole for the new LED. Then a file can be used to smooth the edges for a neater appearance. Slow and steady is the only way to do this without making a mess. Start in the center and work outwards and do not go too deep to avoid cutting into the bezel.

The hole should be perfectly round and just wide enough so the new LED fits.

Wiring the LED

Cut back the LED legs to the little nodules then solder wires from the Chip to the LED. How you wire the LED is entirely dependent on what type of LED you have.

An example of using Borti4938 code with a common cathode LED that has red on the long outer lead and green on the short outer lead.

  • Chip Pin 5 (LO/50) > Resistor > Short outer lead of LED
  • Chip Pin 6 (LO/60) > Resistor > Long outer lead of LED
  • Chip Pin 7 (SET LED TYPE) > Ground point on board (COM) > Middle lead of LED.*

*Chip Pin 7 (SET LED TYPE) and the middle lead of the LED will need connecting to a +5V source if using a common anode LED.

Heat shrink tubing can be put over the individual wire solder connections for better appearance and strain relief, then a further larger piece of heatshrink over all the wires to keep them together. Do not over do this though as the wire needs to be quite flexible in order to fold under the case top.

Once the LED and wires are soldered, the LED will need fixing into the case hole. There are a number of ways to do this.

Hot Glue - Whilst hot glue will not be very aesthetic, it is easy to apply and can be removed with relative ease if the mod ever needs changing.

Milliput - This is much more difficult to do well and more permanent. The milliput can be carefully pushed into the hole and round the LED leads to create an almost seamless surface, but it requires 24 hours to set and it is very difficult to do neatly.

Special Pins

Depending on the code used, these special pins might not be available.

Pin 4 / Reset On Mode Change – When set to (+) or a +5V source, changing the region via the reset button or controller will have an instant affect on the video rate. When set to (-) or ground, changing the region via the reset button or the controller will reset the console and the new region will be set on boot up.

Pin 7 / Set LED Type – When set to CA or a +5V source, a Common Anode LED should be used. When set to CC or Ground, a Common Cathode LED should be used.

Program Your Own

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

D'force3000 (D4S)