1942 pinouts from gopstein@bms.com (Rich Gopstein) Solder Side Parts Side GND A 1 GND +5 B 2 +5 +12 C 3 +12 GND D 4 GND Speaker - E 5 Speaker - Speaker + F 6 Speaker + Coin Counter - H 7 Coin Counter + key J 8 key Shoot 1 K 9 Up 1 Down 1 L 10 Left 1 Right 1 M 11 GND 1 Shoot 2 N 12 Up 2 Down 2 P 13 Left 2 Right 2 R 14 GND 2 2 Player start S 15 GND 1 Player start T 16 GND Coin Switch U 17 GND Service Switch V 18 GND unused W 19 Loop 1 unused X 20 Loop 2 unused Y 21 Vid GND Sync Z 22 Red Green a 23 Blue unused b 24 unused unused c 25 unused unused d 26 unused +5 e 27 * GND f 28 GND * Pin 27 was blank in the manual, but it's probably +5v.