Sega Saturn 50/60Hz Mod
(For details of a switchless mod, have a look here)
A very easy mod to do, if you've done the single switch region mod, then you can get power from that board (top row of diagram for +5v, 4th row for GND), if not, then you can get power from the underside of the motherboard.
You'll need a Single Pole/Double Throw switch and some thin wire, solder the +5v wire to one end contact of the switch, and the GND wire to the other end contact, leaving the middle contact free for the wire needed to send the signal to the graphics chip.
Most other guides for the 50/60Hz switch say to cut a trace on the motherboard and solder a wire to it etc. This can be quite messy, mmmonkey prefers to find the graphics chip (it's the only 160 pin chip on the motherboard apparently, and labelled IC14), on my VA9 motherboard, the chip has 315-5964 printed on it. If your board isn't a VA9, then check Mameworld for info on finding the right chip. Once you've found the correct chip, you'll need to separate pin 79 from the motherboard, mmmonkey heated the solder then used a very sharp thin scalpel blade to pull it upwards away from the motherboard and then straightened it with a pair of small pliers.
Now you've got the leg lifted up, put some insulating tape underneath it, and melt a little bit of solder onto the leg ready to solder the wire on. Prepare the wire by tinning it, and cutting the exposed wire very short, then simply hold it onto the leg and touch it quickly with your soldering iron to join the wire and leg together.
Make sure you secure the wire down properly, you don't want a slight tug on the wire pulling the leg off of the chip! Put some insulating tape over the wire/leg join, then tape the wire down along the motherboard, plan a route so it comes out where the switch is/will be mounted. mmmonkey mounted the switch on the door to the Battery/VCD Card compartment.
mmmonkey has based this guide on the one at Mameworld, make sure you visit and read the excellent guide and FAQ.
I no longer lift Pin 79 of the chip up from the board, instead I cut the trace near the hole and then solder directly onto the leg (not much different to other guides which say to cut the trace of the underside of the motherboard). I just prefer this way, I simply cut the trace right next to the hole, and then add a bit of solder to pin 79 and it's pad, then I solder the wire onto it.
