Replacement IO PCB arrived today courtesy of Heighway. Now the game has become even wilder - without the IO, I only dropped LED's to 1/4 of the PF and a magnet and it's switch but now they are working again they contribute a lot to the rules and shot flow.
I was having intermittent boot probs and the occasional game lockup so thought it best to replace the USB hub as the connectors were just not snug and secure.  Boot and lock up probs now gone. The original hub had substantial corrosion.







Get your money ready for an Alien is what I say.