Williams Solved Grand Prix (Williams, 1976) Stuck in four player

[monsonb]

My Gran Prix sat in a warehouse for over ten years, and I'm trying to bring it back to life. It's mostly working after cleaning all of the switches and polishing the stepper rivets with 600 grit sandpaper and Superlube.
The steppers reset, but I'm still stuck playing a four player game each time. I'm not sure what to check.
Any ideas would be appreciated!

 

[pinballdaveh]

one of the two step units behind the score motor is the coin unit. or how many players are playing a game unit. a common problem is the over-travel of the pin on the gear that opens a NC switch at the units 4th position or 4th player. if the pin shows up under the switch , over-travel has happened. loosen and remove 1 screw from the switch , turn switch out of way of pin , manually reset unit to a 1 player game , return switch to position and replace screw. manually test unit to see if the switch opens when unit advances to 4th player and not before. file clean switch and adjust blades if needed.

 

[monsonb]

Thanks for the reply, Pinball Dave!
I'm not sure what you are refering to when you say, "a common problem is the over-travel of the pin"
What's does the pin look like?
"... on the gear that opens a NC switch at the units 4th position or 4th player."
What gear? And do you mean a NC switch on the player's unit?
Sorry to break apart your advice, but I'm a bit lost.
Thanks!

 

[monsonb]

Okay, I think I know what you are talking about now. Too much eggnog last night...

I'll check that switch on the coin unit. Thanks.

 

[pinballdaveh]

if you have the playfield raised and are standing in front of the machine looking on to the mech board. the rivet discs and wiper fingers will be on left side and the gear with switch activating pin will be on the right side of the units.

 

[monsonb]

I believe the switch is in the right position, no over-travel.

 

[pinballdaveh]

does the coin unit advance and reset correctly when done manually? does the coin unit subtract coil fire during reset on 2 or 3 players?

 

[monsonb]

With the power on, and a game started, I can step up the coin unit to two, three, and four on the backless. When I press the reset coil, the player number goes back to one.

The coin unit doesn't do anything when I try a two or three player game. The machine stays in four player mode.

 

[pinballdaveh]

does the ball count unit reset back to 1st ball when on game over reset? the coin unit reset coil and the ball count reset coils should fire at the same time during reset. there isnt any switches in between them. un-solder the wires to coin unit reset coil , un screw and remove the coil stop , and remove coil, and check its resistance. inspect the coils wire connections at the lugs for solder connections from wire to lugs. sometimes the coil wire will burn off near the lug. if coil has no resistance or cant be repaired , replace the coil.

 

[monsonb]

Thank you for the advice!
I noticed that a wiper blade on the coin unit didn't look like it was making contact. The wiper blade is located almost at 3 o'clock when Coin Unit has been reset. I pulled the playfield to get better access, and I was able to tighten the blade's contact.

Big improvement!

If I press the start button once, I get a one-player game.
If I press the start button twice, I get a four-player game (?)
If I press the start button three times, I get a three-player game.
If I press the start button four times, I get a four-player game.

It's wierd, but it's getting better!

 

[pinballdaveh]

what unit is this pic from?

 

[monsonb]

Coin Unit

 

[pinballdaveh]

the player up unit snowshoe wiper disc in your pic looks odd. the 2nd pic is the way it should look. are connections made on the back side of the wiper disc? could you post a pic of it? the manual shows 12 isolated pairs of connections and their configs. does that match what you have?

 

[monsonb]

A deep cleaning of the player unit's rivets was the solution. I can now play a 1, 2, 3, or 4 player game w/o a problem.

Thank you for your comments and time. I appreciate it.