Swapped the wiring from the aftermarket credit-add switch to doubled-up wiring on the Game Start button. This bypasses the 1-credit problem in https://flipfix.theflip.museum/problem-reports/77/.

This cross-wiring also makes for a more obvious button press, one that our visitors can find.

Also: re-soldered the Test Mode switch wiring so that we can actually enter test mode.

Also: pulled the ROM, cleaned contacts, and replaced it.