RALLY-X Manufacturer: Midway Year: 1980 Genre: Labyrinth/Maze Orientation: Horizontal Conversion Class: See Pinouts DIP Switch Settings: Position Option -------- ------ 8 7 6 5 4 3 2 1 ------------------------------- off off *1 coin for 1 play off on 1 coin for 2 plays on off 2 coins for 1 play on on Free play off off off off 3 cars, rank C, bonus @ 60000 off off off on 2 cars, rank B, bonus @ 40000 off off on off 1 cars, rank C, bonus @ 30000 off off on on 3 cars, rank A, bonus @ 60000 off on off off 2 cars, rank C, bonus @ 40000 off on off on 1 cars, rank B, bonus @ 30000 off on on off 3 cars, rank B, bonus @ 60000 off on on on 2 cars, rank A, bonus @ 40000 on off off off 3 cars, rank C, bonus @ 20000 on off off on 2 cars, rank B, bonus @ 15000 on off on off 1 cars, rank C, bonus @ 10000 on off on on *3 cars, rank A, bonus @ 20000 on on off off 2 cars, rank C, bonus @ 15000 on on off on 1 cars, rank B, bonus @ 10000 on on on off 3 cars, rank B, bonus @ 20000 on on on on 2 cars, rank A, bonus @ 15000 off MAINTENANCE USE ONLY * indicates default setting 'Switch 8 is for maintenance use only and should normally be in OFF position. This halts the microprocessor. If it is inadvertently placed in the ON position, a multicoloured pattern appears on the screen on power up.' I've no idea what switch 7 does. The manual also advises: 'Toggle switches are also found at position 4A on the CPU board. These are for maintenance only and should not be touched.' Looking at the circuit diagram, we see that: Switch1: No connection Switch2: on: pin 21 of ROMS tied to A12 line. Off: pin 21 of ROMS isolated Switch3: on: 'A' input of '139 ROM decoder tied to A12 line. Off: 'A' input of '139 ROM decoder tied high. Switch4: on: pin 21 of ROMS tied to +5V Off: pin 21 isolated My guess is that they select 2716 or 2732 ROMS. 2716: switch 3,4 on, switch 2 off 2732: switch 3,4 off, switch 2 on I have 2716's on my board, and mine are set as shown. ---------------- Mark Sheldon ms01@qits.net.au