This is with reference to a Williams Olympic hockey game I am restoring. See link if interested...

https://pinside.com/pinball/forum/topic/olympic-hockey-#post-4996782

Long story- short question.

I have a problem with the lights coming from the player unit. It controls if player one is lit, or which arrow is lit, and even which side of the advance rollovers light by toggling the transfer relay in a two player game. Its a typical Williams 10 position stepper (I think) and it has a total reset coil. It works perfectly mechanically. I am also highly confident it is working very well in terms of the wiper blades are aligned correctly and making strong contact at each step for each contact.

The weird part is the lights and actions it controls through the wiper blades are mostly not working in a super weird way- by gently pushing and pulling on the disc with the fingers on it I can get the lights to flicker or even stay on. Duh- would be my first response... but what I am saying is that if I manipulate the wiper disc- sometimed just gently pushing it or pulling it across the spindle- I can get the lights to flicker or even stay on but its not because the fingers suddenly made contact. The fingers make great contact. Perhaps a symptom perhaps expected- I measure 6.3 V across the wiper blades for the lights in question- to the stepper unit frame which is a ground point. I always measure voltage to ground across the fingers. They make contact- but if I wiggle the assembly and push and pull on some of the fingers I can get the lights to come on. I suspect That my wiggling is making and breaking some contact point in the assembly of the wiper or between the wiper and the grounded frame of the stepper unit.

I cannot quite figure out the schematic and reconcile it with the grounded stepper frame and the fingers on the wiper. Perhaps some of the fingers are supposed to be in contact with the frame and others not- there are insulted fingers and grounded... if the ground is intermittent would this explain my issue? How should I proceed?

Ok- I was gazing at schematic and I think I can confirm that in fact the fingers should be the path to ground through the stepper unit frame. I also have fully traced the electrical path and will look at the lock relay as possibly having an intermittent contact. I feel like I have a few things to examine and will use a continuity meter to judge where things are going south.

Just trying to write out the issue has helped to clarify in my head a few things to check- I Will post back this evening. Hopefully this resolves

On my to do list
Confirm continuity to frame (ground) between each of the non insulated wiper contacts.

Confirm no continuity to ground for insulated fingers in isolation.

Confirm switches on Lock relay and re-inspect the other switch stacks I have already looked at 12 times that are in this path.

Hi Rolf- thansk for the idea! I went through that uesterday and even removed the ground and confirmed it was all clean and making strong contact so all that looks good. I am checking continuity from wiper fingers to that point as I currently suspect the wiper fingers are not seeing the frame ground.

If I see no continuity between the actual fingers and ground when the lights are off- but find continuity after wiggling it and the lights are then on- I will prbably drop some solder into the inner part of the wiper assembly to promote contact with the spindle and the ground point.

Question-

For a Williams wiper with fingers as Is in question here. Where is the contact to ground supposed to happen. I believe that on some Bally the contact is actually through the silver washers that are held in compression around the fingers. If thats the case here I can try tightning the bolt a bit as I tend to not overly tighten that point as it works against the stepper action being smooth and easy.

I tried to check that by firmly pressing down to ensure contact and was not able to get lights to turn on by doing so- which leads me to think that maybe its supposed to make contact to the spindle and perhaps mine is not doing so.

A few more things a continuity meter check will help with...

Yeah- I will jumper to confirm this is the actual problem. Its weird that it comes and goes with rather slight touches to the wiper disc- would be nice to actually remove that and show the rest of the circuit is behaving itself.

Interesting.

I see no continuity on the insulated finger when going to the frame or the ground wire- this is as it should be.

I see continuity on most of the other fingers to ground and even to other ground points in the head- also how it should be.

But.... when i check continuity to ground for the wiper finger that drives the lights in question I get spotty and inconsistent readings. I can also see this with the wiper in my hands by checking continuity to the metal washer holding it all together- no continuity to that from the finger. I was able to bend the copper at the base of the fingers enough to get some contact with the washer and better continuity. After installed- Lights worked briefly and are now intermittent.

Weird- I wonder if there is a break inside the wiper disc thats causing issues.

I am now in the market for a new wiper- anyone know if these were remade? I think the answer is No for Williams. PBR can apparently make gottlieb wipers, I may give Steve a call and inquire.

Heating the top of the wiper and wicking some solder into the joint between the wiper and the top metal washer seems to have fixed this.

Not the first place I started troubleshooting for this one! Holy cow

Well- not a permanent fix. Not sure what to do at this point. I need to look into this deeper and decide if its really the wiper. Seems to be but no fix now.

Thanks all-

It was two things. The finger disc has some problem where two of the grounded fingers were not in fact grounded. I heated the top washer on the side the fingers were on with a soldering iron and a big tip. Then I wicked solder into the gap. It pulled in pretty good and is almost invisible as a repair. After that I never again found an issue with continuity to ground from the wiper-

My last post suggesting the repair had failed- was correct in that during the repair I had not tightened the wiper disc sufficiently and it would loose ground. Once I tightened it sufficiently its been rock solid through 20+ games. Its fixed for good now.

I did not do precisely this but I was able to convince myself that the oath to ground was working from the assembly. There are other funtions it computes using the other fingers- such as lighting a game over light. Those were fine. So I knew it was either the circuit coming into the bakelite disc or just those two wipers. And then I recognized that I knew it was not the incoming side because I could always get the lights to work by gently wiggling the wiper assebly which of course has nothing to do with the downstream circuit from the lights. So I knew it was in those two wipers- It took me asking for help and thinking through your suggestion before I fully recognized that I actually already knew exactly where it was broken!

Thanks for the thoughts and suggestion. Hope my answer makes sense- your suggestion help me to run the logic loop.