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please help with Space Mission repair

spacemissionmike

New Member
Jan 2, 2023
4
1
3
55
Hamilton, Ontario, Canada
Hi all,
I have a Williams 1976 Space Mission 4 play EM pin...and I need some help with repairs.
-the credit button doesn't work, won't start a new game, reset, add a player, doesn't do anything.
-the game will advance ball 1 through all 4 players but will not advance to ball 2.
-the ball reset relay and score motor continue to run extra long when ball reaches outhole.
-some of the scoring reels do not advance properly or smoothly but work well intermittently and unpredictably.
I want to approach one thing at a time but I'm not sure where to start short of starting at the left side of the schematic and working my way to the right.
any help or suggestions would be appreciated.

thanks, Mike
 

sylvain

Active Member
Apr 27, 2013
209
75
28
Ottawa, ON
It sounds like this project machine has multiple issues and might not have worked correctly for years.

Here's what I do when getting an EM machine in for repairs, or one of mine that did not have a good look over in a while.
I feel there is no point in spending any troubleshooting time until some due diligence is first performed.

Before plugging the machine in:
- in the head, ensure all relays have their contact stacks tight and all screws present
- ensure all relay contacts are gapped correctly - easy to check manually visually by pushing on the armature gently and releasing it
- check that all score wheels ratchet properly and that the switches stacks on each score wheel are tight with the switches gapped/adjusted properly
- confirm that any stepper ratchets properly (e.g. not gummed-up or stuck) and that contacts are right
- Repeat similar steps for relays, score motor and steppers in the cabinet
- Repeat similar steps for relays, steppers and switches under the playfield
- verify that all fuses are good with proper expected ratings (e.g. replace any overfused ones!)
- check that the AC cord/plug is safe
- confirm the coin switches are properly adjusted and not mangled
- check that the tilt bob, incline tilt, slam switch, anti-cheat switch, etc. are in their expected state (check diagram if needed)

Plug it in:
- assemble the machine and plug it in,
- add credits via the coin switch
- start a game and see what issue(s) might be left

Here's a good pinball repair site that should help you along:

Good luck!
 

spacemissionmike

New Member
Jan 2, 2023
4
1
3
55
Hamilton, Ontario, Canada
It sounds like this project machine has multiple issues and might not have worked correctly for years.

Here's what I do when getting an EM machine in for repairs, or one of mine that did not have a good look over in a while.
I feel there is no point in spending any troubleshooting time until some due diligence is first performed.

Before plugging the machine in:
- in the head, ensure all relays have their contact stacks tight and all screws present
- ensure all relay contacts are gapped correctly - easy to check manually visually by pushing on the armature gently and releasing it
- check that all score wheels ratchet properly and that the switches stacks on each score wheel are tight with the switches gapped/adjusted properly
- confirm that any stepper ratchets properly (e.g. not gummed-up or stuck) and that contacts are right
- Repeat similar steps for relays, score motor and steppers in the cabinet
- Repeat similar steps for relays, steppers and switches under the playfield
- verify that all fuses are good with proper expected ratings (e.g. replace any overfused ones!)
- check that the AC cord/plug is safe
- confirm the coin switches are properly adjusted and not mangled
- check that the tilt bob, incline tilt, slam switch, anti-cheat switch, etc. are in their expected state (check diagram if needed)

Plug it in:
- assemble the machine and plug it in,
- add credits via the coin switch
- start a game and see what issue(s) might be left

Here's a good pinball repair site that should help you along:

Good luck!
That's all great advice, thanks for getting me started. I appreciate your reply.
 

John Price

Member
May 31, 2020
75
21
8
Tottenham ON
It sounds like the head, playfield & bottom board are not communicating properly. An important step not mentioned is to clean all the Jones plug connectors in the game, this should resolve most of your problems. For the ball issues, clean & rebuild the ball count unit up in the head, clean & regap the switches on the ball index relay on the bottom board. For the score drums, clean & regap the switches on the 10, 100 & 1000 point relays and the 3 switches on each individual number. You are lucky in that Williams EMs are by far the easiest to troubleshoot. Wish I had the game in front of me, I'd have it running in under 2 hours.