chk your credit unit, can you manually advance it to 4 players? and back again?
it may be wound too far, and a roll pin may be on the wrong side of a switch blade.???
clean/lube/adjust that swing reel.

Hi currieddog
Dr_of_Style mentioned the "Credit Unit" sitting on the bottom - in the middle of the cabinet. This Stepper-Unit has position-Zero (1-Player-Game) - this is the "resetted" position. It can be stepped up to pos-1 (2-Player-Game) then up to pos-2 (3-Player-Game) and NOW by stepping up to pos-3 (4-Player-Game) a "rod mounted on the wheel" OPENS a two-bladed switch having soldered-on: Wire-white-brown, wire-white-blue. IF (if) this switch does FAULTY open too early: The fault in Your pin.
ALSO: IF (if) the spring wound around the axis on this wheel is tightended WAY too much: The mechanical force trying to step-up is not powerful enough. LOOK at the Unit when starting a 2,3 player game - see the plunger on the Unit actuate --- well, and when You try to start for the 4th player: Do You see "just a bit of movement on this plunger" ?

Swing Reel (?) --- here http://www.ipdb.org/showpic.pl?id=972&picno=36603 - the number "between the feet of the old man dancing" ? When the fault happens: It does step a step or two steps (ore more steps) - but not step completely --- OR it does NOT STEP AT ALL ?

IF (if, if) it does some steps but quits stepping too early: On the underneathside of the playfield is mounted: Special Reel Reset Relay. Try: press the armature / anchor-plate of this relay --- does then the Swing Reel steps ? The schematic is a bit complicated - please write about " It does step a step or two steps (ore more steps) - but not step completely --- OR it does NOT STEP AT ALL ?", greetings Rolf

Hi Currie. oops, my bad...I was referring to the player unit.
if the game has credits, it shud go to 4 players if you want.
chk the player unit carefully.
it shud manually go from 0 to 4 players, then reset back to 0 without hangin up.
clean/lube/adjust.