Megadrive 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 Megadrive 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 Megadrive 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 Megadrive 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 Megadrive, 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 Megadrive 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 Megadrive 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)
