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.