Welcome - you have come to the right place for help on maintaining your machines (I say 'machines' - plural - hahaha).
Stick an add in the local neigbourhood paper 'wanted to buy' and put up notices on the board at BigW etc - I have had great success that way - I bought a Bally Space Invaders Pinball for $500 that way.
Also whack ads on Gumtree and any other 'local' type sites -
"wanted to buy - pinball machine - anything in any condition considered - no fancy prices please"
...or words to that effect - be patient and something will come along, doesn't really matter what it is as long as the price is right - you can repair it/trade it/swap it from there.