Welcome to the forum...
A lot of good Amiga stuff was designed and manufactured in South Australia such as the Phoenix A1000 replacement board.
As for the Amiga 500+ remove the RTC NiCad battery (if it has not been done already) as old batteries will leak and cause corrosive damage to the motherboard.
If you do wish to keep the RTC function replace the battery with either a coin battery hack
http://aminet.net/search?query=lithbatt or place the replacement battery far away from the motherboard.