Mega Drive 1 50/60Hz and Jpn/Eng Switches
It is possible to modify your MD1 and control all of the region and video mode using the reset button.
A Mega Drive 1 is actually very easy to modify, you can fit 2 switches, one will swap between 50Hz and 60Hz, the other will swap between English and Japanese language.
Using these switches, you can configure your Mega Drive to be European, Japanese or American (a Genesis). You can force all your games to run full-screen and full speed (PAL 50Hz runs 20% slower than 60Hz), and if you widen the cartridge slot then you'll be able to play absolutely any Mega Drive game.
Equipment needed, 2 switches (single pole, double throw) and some wire. Most people use toggle switches, mmmonkey prefers sliding switches. If using sliding switches make sure you get break-before-make ones, and you'll also need some screws/bolts to hold them (mmmonkey's local supplier only has double pole, double throw, so only one row of connectors will be used on each switch).
Totally dismantle your Mega Drive, the motherboard is linked to the LED on the upper part of the casing, do not cut the wires for the LED, simply straighten the legs and pull the connector off of the LED, the longer leg of the LED joins the red wire.
Remove all the innards, so you end up with the the bottom half of the case and drill the necessary holes to fit your 2 switches. It's a good idea to fit the switches to the left hand side or the rear of the console so that they don't interfere with a MegaCD unit. mmmonkey has taken apart a sliding switch to use as a template
Hold the switch inside the casing, and use something sharp to mark where the 2 screw holes need to be drilled (do this twice obviously)
Drill out the screw holes, then attach the switch template, and drill and file out the rectangular hole where the switch will poke out
Now attach both the switches into the case. Melt some solder onto each of the contacts onto the back of the switch, then replace the metal shielding and the motherboard. To the right of the motherboard you should see 4 sets of pads, marked JP1 through to JP4. On a PAL Mega Drive the middle two are linked up, using a sharp knife to cut the links (mmmonkey makes 2 cuts very close to each other, then picks the link between the 2 cuts out). Then heat up each point with a soldering iron, melt some solder onto it, to form a nice little round blob. (Your points may be in a slightly different place, and have a blue capacitor on JP1, leave the capacitor in place and work around it).
Prepare some wire, strip the end of the wire, twist it, then "tin" it (heat up the wire, then press some solder onto it, the solder melts and the end of the wire should now be coated with solder), then trim the tinned wire, so only a little bit is showing. Make sure the piece of the wire is long enough to reach the switches, about 14" is enough, you'll need 6 pieces of wire, 3 different colours makes the job even easier.
Jpn/Eng switch
Now, hold the wire flat on the motherboard, with the exposed tinned end over the following point (the left side of JP2), press the soldering iron onto the wire, all the solder should melt together (some guides say you need to link 2 points together, mmmonkey found this un-necessary as they were already linked on the underside of the motherboard). If you can be bothered, each of the points you have to solder onto are actually holes in the motherboard, you could push the wires through the holes whilst soldering them (there are examples of this on most Mega Drive motherboards).
Repeat, for the following points, using different coloured wire like this makes the job very easy.
The first wire (purple in this case), should be soldered to the middle contact of one of the switches (mmmonkey used the switch nearest the rear of the console), the wire from JP1 was soldered to the contact near the rear of the console (white in this case), the wire from JP2 (yellow), should be soldered to the remaining contact on this switch. (also notice the "tinned" contacts on the other switch)
50/60Hz switch
Take a look at the picture below, look which wires to solder to the prepared pads. Then look at which order to solder the wires onto the contacts of the switch.
That's it, put the upper shielding back on, mmmonkey routed the wires out of this hole near the controller ports, and tucked them under the headphone socket board (shown lifted up in this picture). This way the wire doesn't interfere with the on/off switch, volume control or the case.
If required, widen the cartridge slot so Japanese games will fit, then re-attach the LED and put the case back together. Be sure that the volume control and on/off switch line up properly when re-assembling!
mmmonkey has used a Dymo Letra Tag machine to label the switches. Here's the switch placement, hidden away, but still easy enough to use.
The following pictures show a Mega Drive running a PAL copy of Streets of Rage in 3 different modes, UK (Eng 50Hz), US/Genesis (Eng 60Hz) and Jap (Jap 60Hz), notice the size of the image and the name of the game changing depending on the selected mode.
You also need to know that unless you use an RGB Scart cable, the picture of the 60Hz mode will be a very bad quality black and white image (regardless of whether or not your TV accepts an NTSC signal or not). You can buy an RGB cable from shops on our links page, or you can make one yourself (mono or stereo). The reason break-before-make switches are used is so that you can safely use the switch whilst the console is switched on, useful if you want to play an American game that will only start up in US/Genesis mode but your TV doesn't support 60Hz, you can start the game in US mode, then switch to UK mode and play the game.
Update - there are many different MD1 motherboards, another common one has a capacitor on JP1 (JP's 1-4 are located in a slightly different place). Many people have emailed asking how to mod this, I emailed this diagram to Santiago Romero who tried it out and confirmed it worked. Santiago also provided a photo showing where the JP points are (follow the wires coming from the switch in the top right of the photo) - thanks Santiago!
There are some games that refuse to start if the machine is set to a different region than the cart expects. This is Street Fighter II Championship Edition refusing to start.
A big credit must go to SegaXtreme, this guide is based very heavily on the one featured on this site, with a few minor alterations introduced by mmmonkey.
Here's a brief explanation of how the jumpers are configured. The photo below shows JP2 and JP4 linked up, this is PAL console.
JP1 and JP2 controls the language of the console (GND for Japanese, +5v for English) - the 2 points on the left (highlighted in green) are linked on the underside of the motherboard.
JP3 and JP4 controls the video mode (GND for PAL, +5v for NTSC) - again the 2 points on the left (highlighted in blue) are linked on the underside of the motherboard.
All the switches are in the guide are doing is controlling which of the GND/+5v on the right is linked to the point on the left.
Summary of Components needed
2 x Single Pole, Double Throw
switches
6 x lengths of wire
