Rally X Midway, 9 January 1981 ------------------------------ Logic Board I, part. no. A08291385C000 PARTS SIDE | SOLDER SIDE -------------------------------------------------- (+5V) Gnd | A | 1 | Gnd (+5V) (+5V) Gnd | B | 2 | Gnd (+5V) +5V | C | 3 | +5V +5V | D | 4 | +5V (?) Credit Mult. | E | 5 | Power Credit Mult. (?) (Not Used) | F | 6 | Coin Meter Coin Sw. | H | 7 | NC (?)* 1P Start | J | 8 | 2P Start P1 Up | K | 9 | P2 Up P1 Down | L | 10| P2 Down P1 Right | M | 11| P2 Right P1 Left | N | 12| P2 Left P1 Smoke | P | 13| P2 Smoke Credit Sw. | R | 14| Test Pos. | S | 15| Gnd (Cocktail only) (Common) Gnd | T | 16| Gnd (Monitor) Red | U | 17| Green Blue | V | 18| Comp. Sync Spkr | W | 19| Spkr +12V | X | 20| +12V (+12V) Gnd | Y | 21| Gnd (+12V) (+12V) Gnd | Z | 22| Gnd (+12V) * NC may *not* mean "No Care" for this pinout. I can't figure out what it does exactly, but it does have traces in the schematic similar to the other buttons, controls, and switches. Elsewhere on the schematic (pin F) there is a "N.C." which is, I'm sure, a "No Care" pin. I have a clone board which has 2 boards connected by 2 IDC cables. My board has two sets of DIP switches, an 8 way at 11E on the video/sound board, and 4 way on the CPU board. 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. : 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.