Big thanks to Dan (Riverinapinball) coming over after work today and helping me get started with the dead short fault finding.
As expected, the transformer was now toast and smoked with nothing plugged into it when powered on. Dan tested the oddly placed small transformer up the back of the cabinet. It had a short. It was also burned like the main transformer. Maybe it was the first to fail and then the main transformer cooked. The main transformer connected to this via a blue cable and it seems someone has spliced this to the small transformer and then up to the fluoro/ballast in the headbox. The ballast looks like it originated in Europe and was very weathered looking. One of the wires fell out when I lightly pulled on it.
What's next? Going to bypass the small transformer and run directly from the transformer up to the fluoro/ballast. Also going to remove the ballast and replace it with a brand new Australian ballast. Might also replace the fluoro switch for good measure. Dan is going to come back and help me test everything before I purchase and install the new transformer.
I welcome Dan to chime in if I have missed anything and if anyone else has other suggestions. Going to go back through this thread and read all the responses again.
Cheers!
Adam.