Sega Saturn VA0 Switchless Region Mod Install Guide

Work in progress

Mod Pinout

Solder Map

This mod requires 4 trace cuts, solder mask removal of 1 via, removing the original LED, soldering 11 points (10 wires, 1 through hole pin of the replacement LED).

Region Jumpers

The jumpers control the region of the Saturn by being connected to ground or supplied 5V in various ways. This is permanently set on the Saturn mainboard but can be overridden by cutting the ground connection or 5V supply and controlling these via a modchip.

The jumpers are usually in pairs JP1/JP2, JP6/JP7, JP10/JP11, JP12/JP13.

The jumper pairs share common pads that are connected by a thin trace. They will then have two adjacent pads, one is a ground point and the other is a 5V supply.

On this revision (837-11493 PAL VA0), JP1/JP2 is connected to ground via a component.

JP1/JP2 (50/60Hz Video Rate Switching)

JP1/JP2 is connected to Pin 79 of VDP2 and it is this pin that controls whether the Saturn is in 50Hz or 60Hz. When it is connected to ground, the Saturn is in 50Hz. When it is connected to a 5V supply, the Saturn is in 60Hz.

Method 1 - Lifting VDP2 IC14 Pin 79

A popular method of achieving 50/60Hz switching is to lift VDP2 IC14 Pin 79 and wire the 50/60Hz video switching pin of the modchip to this. There is no technique that makes lifting a pin safe, it can take only 2 or three bends to stress metal to the point of breaking. If this is the chosen method it is important to be careful when lifting the pin.

Method 2 - Jumpers

This jumper resides on the bottom surface of the Saturn mainboard.

My preferred method for achieving correct 50/60Hz switching is to remove the component connecting JP1/JP2 common to power/ground. Once this is done the modchip can be wired to any point of the Saturn mainboard that connects directly with VDP2 Pin 79. This includes the common pads of JP1/JP2, 1 via which will need scraping of solder mask or VDP2 Pin 79 itself.

VDP2 Pin 79 does not need lifting if you remove the component from the JP1/JP2 jumper.

JP6/JP7, JP10/JP11, JP12/JP13

These jumpers reside on the bottom surface of the Saturn mainboard.

The traces connecting the common side of JP6/JP7, JP10/JP11 and JP12/JP13 to the power/ground side will need cutting. These common jumper pads all have traces that come out on the top side of the board through vias and then terminate at IC9, pins 5, 7 and 8. Solder wires from the modchip to either the vias once solder mask has been removed, or to the pins themselves.

It is also possible to solder the wires to the common jumper pads, but it is difficult to rout the wires from one side of the Saturn main board to the other, so it is best to use the vias or IC pins.

Reset

The reset points reside on a separate Saturn daughter board. There are alternative points on the Saturn mainboard whic will be included soon.

LED

The LED is on a separate daughter board. The original LED will need removing. The new LED can be secured by using the original LED ground point.

Work in Progress