This is a multi-game hack on a standard Galaxians PCB. It allows you to select from 4 different games on power-up or reset. It is not too tricky to install since all games use the same colour prom. Files needed and instructions to install this on your own PCB are printed below.
You first need to download these files and then follow these steps. All wire links can be made with signal wire, tidying up afterwards with spots of glue from a glue gun to hold the wires in place. (it’s best to complete installation and test it before doing this)
- Program fourplay.bin into a 27512 rom and graph1 and graph2 into 2732 roms
- Remove rom board and Graphics roms
- On a 28 pin socket (or the 27512 programmed earlier) bend out pins 1,2,20,22,23,26,27 and 28
- Insert socket (or rom) into socket 7F aligning pin 14 to original pin 12. Pins 1,2,27 and 28 will overhang the end.
- Connect links as follows
- Pin 28 to 7J pin 24 (+5v)
- Pin 2 to 7D pin 5 (A12)
- Pin 20 to 7J pin 12 (CE)
- Pin 22 to 8E pin 13 (OE)
- Pin 23 to 7D pin 3 (A11)
- Pin 26 to 7D pin 7 (A13)
- Pin 27 to 9N pin 6 (A14) Switched by Menu
- Pin 1 to 9N pin 7 (A15) Switched by Menu
- Bend up pin 21 on both graphics roms
- Insert graph1 in 1H, graph2 into 1L
- Connect pin 21 of each graphic rom to 9M pin 4
If all this has been done sucessfully, then power-up should give you a menu listing the 4 available games. Select which game you wish to play using left and right, press fire to start the game.
If you wish to add a button to return you to the menu, then you can extend the on-board reset button to an unused button in the harness, or add an extra button.