Does it have the power supply in the backbox? If this is missing you will need one if you plan on using a NiWumph board. If you use pascal board you can buy an all in one board that has the power supply, CPU and driver board all in one.
If you need an old but working power supply board and driver boards PM me as I can probably get these for you at a resonable price. Or you can buy new replacment power supply and driver boards (Try "RTBB" Greg may have them or may be able to source them for you)
When you say changing tappings are you reffering to the transformer in the bottom of the cabinet? If so and if this machine is from France you shouldn't need to as they operate on 240V also. May need to replace the plug on the power cable to one of Australian Standards type if this hasnt been done. Always a good idea to check the earth wires are connected and operational also and use an RCD for safety purposes (safety switch if your house has one or use a portable RCD, if it doesnt).