What did you clean and lube?

Generally the stepper should advance if you press the solenoid plunger all the way in and let it go. If it can't do that reliably from each position to the next you've got some friction to address. Possible reasons include:
- Shoulder bolts are too tight as you suggest. The arms that pivot around them should pivot freely.
- Contacts are worn so snowshoes snag on them as they try to slide over them.
- Showshoes don't slide easily in their shafts so they bind against the contacts.
- The gear shaft is gummed up and doesn't spin freely.
- The stepper arms don't reach far enough to grab the next gear tooth.
- The gear shaft spring is wound too tight. Four turns is about right.
- The solenoid plunger is worn or mushroomed and drags inside the coil sleeve.
- The contact board needs to be cleaned or polished.
- Pivots on the advance or reset arms are binding.

If everything has been cleaned and there's no excessive wear, little to no lube should be necessary.

/Mark

Mark covered it, but blowing up those pictures, the rivets look pretty gnarly to me. Use some 600 grit wet/dry sandpaper or a Scotchbrite pad on them, then clean with some rubbing alcohol and use a very thin coat of lube on them. You want a synthetic lube that won't harden.

The fact that it hangs up only in those spots makes me think it's not the shoulder bolt causing the mechanism to bind.

Those pics were taken before the service. It would be useful to post pics of the 'after service'.

Here is a pic of my replay stepper, but the same applies to the ball count unit. The screw that is circled should not be cranked down too tight. That pivot arm needs to be able to move. Back the screw out a little and tighten the nut while holding the screw. A small dab of Super Lube would help also.
Make sure the gear is pushed forward all the way before tightening the spider arm.
Try using Noxon brass cleaner for the contacts points. A drop on a micro fiber cloth will polish those up nicely. No sanding necessary.
Here's a pic is my ball count unit contact plate after polishing.

IMG_2570 (resized).jpgIMG_2602 copy (resized).jpg

Another thing that people do incorrectly with these steppers is to position the wiper arm mount too far in on the shaft causing the shoes to ride at the far end of their spring (and can cause gouging of the rivets). Just something else to look at. I try to position mount at 1/3 shoe travel. This is a frequent problem with roto target mechs as well.

Ken

I would disagree with no sanding if the rivets are heavily scored.

Me too...I never "polish" those...just a Stotch-brite pad cleans them up nice. The "sanding" your doing with a SB pad on a rivet like that is inconsequential.

What does the stepper unit do, I thought this was the ball in play unit?

it is... of course it also has contacts to shut the gameplay off at game over (backside stacks).

Top row of rivets, ball in play lights, bottom row of rivets, signals GO at 3 ball or 5 ball. A common issue is where the tab for GO leads will get loose/electrically isolated from the rivets. One "hack" is to rotate the tab to the right/left past its "arm" thus putting pressure on the point. Proper fix is to solder the revit fix on the backside after demounting the bakelite board.

Gottlieb mystery part number A-15480 or
A-15?480. Can anyone identify this? It came with my Eldorado, but may be from a number of machines.

20240309_112416 (resized).jpg

its a guide to hold the backglass inplace. Goes in the front corner on the edge of the glass.

Thank you sir!