(Topic ID: 235934)

Gottlieb Rack-A-Ball - Learning the Hard Way

By pinballonmars

4 months ago

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  • 22 posts
  • 7 Pinsiders participating
  • Latest reply 4 months ago by pinballonmars
  • Topic is favorited by 4 Pinsiders


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#1 4 months ago

The benefits of inviting your neighbors over for Christmas dinner? Sometimes they have pinball machines sitting in their garage that they're trying to get rid of. And so I've inherited a 1962 Gottlieb Rack-A-Ball in unknown working order. It's been in their garage since the 1980's, but it's unclear when it was last used.
My goals are modest: get it working and try to knock off most of the rust and dirt. This is my first time owning and restoring a pinball machine, so I'm assuming this will be a learning adventure. I'll try to document what I've learned along the way, in case it helps it other newbies and to give credit to those who've written guides that helped along the way. I should mention this is my paternity leave project, so it will be done between diapers and feedings, and handling the other toddler. In other words, in fits and starts.


#2 4 months ago

Initial Assessment:
- Playfield glass is missing
- Playfield is dirty and worn in some places, but looks like in pretty good shape overall
- Ball shooter lane is worn down to plywood near plunger
- Rubbers are all crumbling and in some places melted to playfield
- Legs, coin box, and most other chromed iron pieces are rusted significantly
- Original (or at least old) power cord is ungrounded and looks particularly sketchy
- Backglass looks in good shape, but score reels are discolored
- Cabinet has yellowed and has scratches, but stenciled patterns still show up well.

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#3 4 months ago

First step: disassemble the playfield as much as possible to prepare for top surface cleaning and waxing.
Basic method: take lots of pictures for each component, bag all the parts into Ziplocs, and mark the bags with the name of the playfield parts.
Lessons learned:
- Take even more pictures than you think is necessary
- Take video wherever the components have a complicated assembly
- A bag organization system would be better than my 'throw everything in a Tupperware' system.

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#4 4 months ago

Here's the guide that I give credit for fixing everything: http://www.pinrepair.com/em/index.htm

Here's where to get the parts: http://www.pbresource.com/

.... except for playfield glass. That comes from a local glass shop. He can get me a couple pieces of 21" X 43" X 3/16" tempered glass for less than the parts guys charge for shipping. Sometimes he even remembers to order it without the "bug"(little etched logo in corner).

Looks like you inherited a pretty decent example of a Rack a Ball - congrats and yeehaw!

#5 4 months ago

Now to remove all the lightbulbs. I didn't have a bulb remove/insert tool unfortunately, so I was left using fingers and needlenose pliers. That means I broke a few bulbs as well. One puzzle: there seems to be a mix of the regular #44 bulbs and some rounder bulbs (later found them to be #55 bulbs). Not clear where the 55s are used or why.
I also wanted to remove the bulbs behind the backglass. I knew how to open the backbox, so I tried to remove all the bulbs from the back of the backbox. That was really annoying and fraught with broken bulbs. Only then did we realize we could remove the backglass to make it easier.

Lessons Learned:
- I didn't actually know the locking mechanism on the bulbs, so I was just trying to unscrew them. After ripping out a few the hard way, I eventually learned to press down before the quarter turn to remove the bulb.
- Make or buy a lightbulb removal tool - it makes everything easier.
- Remove the backglass to remove the other bulbs.

Here's the playfield stripped as well.

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#6 4 months ago

The #55 bulbs are there because someone had them and they light up at 6 volts. They do not belong in there. The 55s and also the 44s can be replaced with #47 bulbs which run cooler, causing less damage to plastics and backglass.

#7 4 months ago

So now for my first (possible) mistake. In my haste to get started with supplies on hand, I cleaned the playfield with Simple Green. It worked great to get the grime up, but I learned later that water-based cleaning agents shouldn't be used on the wood playfield, especially if you're worried about the top surface. I haven't seen any negative effects, but I'll try to avoid that mistake in the future.

That night I started my Google search for help on pinball restoration, which led me to Pinside and several helpful guides:
- Playfield restoration: https://pinside.com/pinball/forum/topic/vids-guide-to-ultimate-playfield-restoration
- Cleaning and Waxing: https://pinside.com/pinball/forum/topic/cleaning-and-waxing-pinball-machines-vids-guide

Lessons Learned:
- Read the directions first.
- Vacuum first. I don't have a Shop Vac (soon to be rectified), so I ended up using the hose from our regular vacuum.
- Don't use water-based cleaners for old playfields.
- Be patient and get the right materials.

#8 4 months ago

The small white tip on the ball plunger (a new one) makes a great bulb remover, order an extra when you order a rubber kit.
I like it, old, classic art.

#9 4 months ago

Next step: figure out how to remove the rust wherever possible.
I started by removing the all of the metal parts on the front panel, all of which were quite rusted (see below). I'll wait on the legs until I've figured everything out. I learned my lesson about photos and video, and I took a lot more videos for the disassembly of the coin slots and returns.

After disassembly, I went to Google and Pinside to find a solution. And behold, I learned about Evaporust.

Sounds like I need to start filling up an Amazon cart.

Lessons learned:
- Use a clean towel below the work surface to catch fasteners when your fat fingers drop the parts.

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#10 4 months ago

First supply ordering session, and several lessons learned.

In my excitement and haste, I immediately ordered a parts kit for the Rack-A-Ball from Ebay that came with a rubber kit, #44 bulbs, springs and rubber for the ball shooter, fuses, and some sketchy Pepto-Bismol looking cleaner/wax. I wish I had spent more time preparing an order and went with a different vendor, because there are other parts I needed and shipping costs eat you up on small parts.

Next, I went to several local stores (Home Depot and Ace Hardware) looking for Naphtha and Evaporust. No luck on either, so back to the internet.
That's when I learned, as usual, California is making things hard on me. California has banned Naphtha from stores, probably something to do with cancer. But there's a loophole - you can purchase it online in volumes of less than a gallon. Amazon won't let you order the 1 gallon varieties, but the 1 quart option is okay. I briefly considered asking my parents to bring some when they came out to see the baby, but I wasn't sure how excited TSA would be to see flammable paint thinner in their checked bags.

Lessons learned:
- California banned Naphtha from store sales. Buy online in quantities less than 1 gallon.
- Shipping costs are a big portion of small orders, so make sure to get your money's worth by combining orders.

#11 4 months ago

Now while waiting for some of my orders to come in, I turned to doing the checkout of the internals. I found a great guide for EM restoral:

So I started with the "Before Turning the Game On" section:
I had to run out to Harbor Freight to buy a multimeter (I'm slowly stocking my toolbox based on this project) for this work. I'm spoiled by high-end Fluke DMMs at work, but I settled for a reasonably cheap HF DMM with some extra alligator clips.

Work done:

1. Check all fuses.
I didn't make the fuse tester from the guide (maybe if I do more games), but all of the fuses checked out with the DMM.

2. Check coil resistances.
We have a similar process at work (I work on the Mars Rovers) called Electrical Integration Procedures where we work through all power-off measurement of electrical components, so this section made sense to me. I made an expectations table to at least give me a rough estimate of what I should see; I later found similar pages, but I made mine from the schematic and parts websites. See screenshot below.
During the process, I found that the Hold Relay had a short. Apparently it's the most common coil to burn out, since it is held on the whole time the machine is on. It even looks burned out - the surrounding paper sleeve is burnt to a crisp. Sounds like I'll have to replace it.
All other coils check out, so I'm moving on.

3. Clean Plug Connectors.
Sanded the corrosion off of all of these with 400 grit sandpaper. Even if this wasn't necessary (it probably was), it was a good learning experience to learn where all the plugs where in the future where I need to disconnect plugs.
I missed/skipped cleaning the light sockets, and in retrospect this may come back to bite me.

4. Checking Switches
The guide recommended this for coin door switches, but I decided to do this for every switch. For every switch I could find (some of the bank and motor switches were too hard to easily access), I checked that the default state was correct according to the schematic and when the relay moved the switch changed the state (open to close, or vice versa). This was a good exercise in understanding the schematic and translating that to physical space. I read schematics often at work, but the formatting is pretty different and I'm used to DC power instead of AC. One additional wrinkle: the wire colors in the schematic are helpful, but in 47 years a lot of the colors have faded beyond recognition. Is that Brown-Red-Orange or Red-Yellow-White?
Along the way I found a few cases where the switch blades were bent incorrectly and weren't making correct contact, so those were adjusted with tweezers/needlenose pliers.


5. Cabinet Cleanup
Along the way, I found several loose parts in the cabinet. Most were fasteners, but I found one bakelite triangle that was totally unclear where it went. At this point, I just bagged it and hoped I would figure out where it went (spoiler: I did!).

On to the stepper motors and score coils, which deserves a separate post.

Lessons Learned:
- Most DMMs don't have auto-ranging features. Make sure you pick the right range for your measurement. If you pick a resistance range too small, the circuit will register as OL, which can mislead you.
- Schematics are not physical representations. Things next to each other on the schematic may be very far apart physically, including in different segments (backbox, cabinet, playfield underside).
- The switches actuated by relays are not always near the relay in the schematic, or even the other switches on the relay. Have to look for the relay letter on switches all over the schematic. Once you start understanding the circuits, they're a little easier to find.

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#12 4 months ago

You can get new legs, levelers and bolts from pinball resource. Not very expensive. The yellow on the cabinet may be nicotine that should clean off fairly easily. Taking it off will make a real nice difference

#13 4 months ago

Thanks to sulli10 , phil-lee , and balzofsteel for the pointers. I should have mentioned that these first few posts are retrospective on work already completed, so some of the items I've figured out (ordering supplies from PB Resource, e.g.), but all advice and help is greatly appreciated.

#14 4 months ago
Quoted from sulli10:

You can get new legs, levelers and bolts from pinball resource. Not very expensive. The yellow on the cabinet may be nicotine that should clean off fairly easily. Taking it off will make a real nice difference

Do you have good suggestions for removing the nicotine stains? I tried a bit of Simple Green and gentle scrubbing (I'm a little afraid of removing actual paint), but didn't have much success.

#15 4 months ago
Quoted from pinballonmars:

Do you have good suggestions for removing the nicotine stains? I tried a bit of Simple Green and gentle scrubbing (I'm a little afraid of removing actual paint), but didn't have much success.

I have used a magic eraser and alcohol. As with any method go slow and easy and watch for signs of paint removal.


#16 4 months ago
Quoted from pinballonmars:

Do you have good suggestions for removing the nicotine stains? I tried a bit of Simple Green and gentle scrubbing (I'm little afraid of removing actual paint), but didn't have much success.

Krud Kutter.

#17 4 months ago

On to the stepper motors. This step definitely gave me the most trouble and seemed prone to error, but in the end, I think I got it done.
I followed http://www.pinrepair.com/em/index2.htm#steps for this step, along with a few YouTube videos so I could see the physical assembly and pieces.

In addition to the score reels (next post), there are two steppers on the Rack-A-Ball: the 0-9 Unit, which is a Continuous Rotation stepper unit (only a single solenoid to increment the units, and the Ball Rack Advance Unit, which is a Total Reset stepper unit (two solenoids, one to increment, and one to return to Home). The Rack-A-Ball has a pool ball concept in the backglass, and the Ball Rack Advance Unit helps count the number of balls displayed (presumably for a Replay match).

0-9 Unit
This one was a little easier, both because it only had a single solenoid and it was in better shape. See first image for front side and second image for back side. I disassembled this one slowly and with lots of photos, but I wish I had just videoed the whole thing.
I cleaned all the parts with alcohol and 3M pads or Q-Tips for the tight spaces. Then I sanded the bakelite rivets with fine grit sandpaper until they were shiny again, and then lubed the bakelite plate with Superlube very lightly.
Reassembly took several tries because of the tight alignment of some of the screws, but I eventually got it. After reassembly, I checked manually to make sure the stepper worked correctly and each step left the 'snowshoes' correctly aligned on the bakelite rivets.

Ball Rack Advance Unit
This one was a lot more troublesome, but it solved my first mystery - the extra bakelite plate! After working on the 0-9 Unit, I understood the stepper unit mechanics better and could clearly see a wiper plate missing (see third picture). So that's solved - but the next question would be - what is the right alignment? In the guide, it emphasizes marking the home point of total reset steppers, so that you know how to realign when you reassemble. But that's a problem for reassembly, so I can defer it.
A key step I messed up on disassembly: I accidentally released the rotational spring that helps reset the stepper. That meant that I wasn't able to count the number of times it uncoiled (a recommended step in the guide). That gave me problems when I went to put things back together. It took several trials before I found the right number of turns to give enough tension on the mechanism for resets, but not too much tension to prevent resets. Also, bending the spring to hook back into the eyehole holder was difficult - I had tweezers and needlenose pliers, but it was difficult. What do other people use?
Again, same process for cleaning: alcohol, sand paper, and Superlube on the bakelite. Time for reassembly and alignment.
After a lot of trial and error, the stepper was back together. So how do you align it? Thankfully, there are a few clues. There are only 6 pairs of rivets on the bakelite plate (see photo). These pairs correspond to balls 7-12 in the display; this is clear because there's a score adjustment feature to pick what the minimum number of ball is for a replay, starting at 7. Since there are only 12 balls, we know that the last rivet set is the maximum rotation for the mechanism, so we can start there and work backwards. Again after some trial and error, the wiper plate is aligned. I test by resetting the mechanism, and then actuating the increment counter. Once I get to 7 clicks, the first set of rivets are aligned on the snowshoes, and each further click up to 12 aligns with a rivet set. Victory!
One last issue: I notice that the wiper arm is missing a wire between the two snowshoes. Again, this is clear because I previously worked on the other version, which has the wire, and because it makes sense electrically. So I'll need to acquire some wire and connect it. Add it to the To-Do list.

Lessons learned:
- Setting up video on a tripod for complex disassemblies would be very helpful.
- When manually actuating solenoids, make sure to do it with some force. When electrically driven, it will be fast and the kinetic energy is necessary sometimes to move stepper states.
- Count spring 'unrotations' when untensioning rotational springs, so that you can retension the spring later.
- Align the Ball Rack Advance Unit using the last set of rivets on the bakelite plate to the last step in the mechanism.

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#18 4 months ago

I have had this game since 1969. Unfortunately it went through my teenage years. My game is completely operational and I still play it regularly. The playfield is in decent shape but the cabinet was spray painted and needs much work.

I have been collecting parts for several years to restore it to it's former glory when I retired. Well, I retired a few months ago. I am planning a cabinet rebuild/repaint (I have stencils), playfield touch up, and complete cleaning of all the electro mech. I also got a repro backglass several years back since my backglass is very poor.

If I can help with pics of parts on my machine or anything else, please let me know. I am looking forward to seeing how your restore goes.

#19 4 months ago

And now for the Score Reels! Again, following http://www.pinrepair.com/em/index2.htm#reels , I disassembled, cleaned, and reassembled the score reels. In particular, I focused on the Units reel because it didn't seem to step well when manually actuated.

Once I cleaned and went to reassemble, I learned another lesson in documentation and also in the good forethought by the designers. Above the bakelite plate with rivets there is a copper plate with a single wiper. That plate fell off when I disassembled, so I didn't get to note its alignment. When I went to put it back on, I realized my problem. To solve the problem, I attempted to align it by using the schematic. I was able to figure out the 0 rivet, and I tried to align the wiper at that rivet when I knew the score reel would be at 0. However, this didn't seem to work.
Then I realized that the designers were smart enough to anticipate dummies like me. They had sized the plastic alignment posts in two different sizes and the copper wiper plate also had the same different sizes, along with the outer alignment as well. I think the Japanese TQM folks call this poke-yoke, but I'll just call it good design. Once the alignment posts were in the right holes, everything lined up - the wiper was on the 0 rivet when the score reel displayed 0.

Lessons Learned:
- Be careful for hidden parts in disassembly. Sometimes they fall out when you should have checked their alignments.
- Watch out for alignment features that are unique to aid in reassembly.

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#20 4 months ago

The Evaporust arrived, so it's time to try out the magic stuff. I started with the front panel components before I move on to trying the legs. I cleaned everything with a bath in Simple Green before dropping into a flat tupperware container with the Evaporust.
After 24 hours, I took everything out, scrubbed it with a wire brush and 3M pads, and then back into the Evaporust.
Another 24 hours later, and everything looks pretty good! Check out the before and after photos.

Lessons learned:
- Wear gloves when using baths of Simple Green for parts. That stuff will dry your hands out for days.
- Having a variety of form factors of plasticware for bathes is very useful. Evaporust is expensive, so using the right container for each group of parts is very helpful.

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#21 4 months ago

Continuing on the power-off electrical work, it's time to replace the sketchy power cord with a grounded version. This one is pretty straight-forward, following:

I overdid it buying a 14 gauge cord, but it was the easiest option on Amazon. After cutting the existing power cord and desoldering the posts, I tried to remove it by cutting the wire bundle gut before I realize that's a bad idea and just leave it.
After soldering in the hot and neutral lines to the transformer, I connected the ground wire to the post of the transformer. I need to go back and add a ring terminal for the ground wire - right now it's just crammed in between the bolt and the nut. I also would like to add a ground braid and ground the other component, as vid1900 's guide recommends. Always more work to do!

Lessons learned:
- Don't cut the gut wrapping the existing wire bundles to pull out the old power cord. Just leave the old power cord in the wire bundle, it won't hurt anything.
- Buy wire strippers.

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#22 4 months ago

Now I get to the part I've been dreading: trying to repair the shooter lane. Electro-mechanical stuff I can handle and understand from my day job, but woodworking, painting, and basically anything artistic is outside my wheelhouse. I've decided to do enough to make it workable and not hideous, but not go for pristine work.

You can see from the first photos that the wood near the plunger has been scuffed pretty deeply, revealing lower layers of the plywood. In addition, the ball trail up the lane is also pretty rough and has worn out the top stain. So what to do?

I'm using vid1900 's Playfield Restoration posts about the shooter lane (https://pinside.com/pinball/forum/topic/vids-guide-to-ultimate-playfield-restoration/page/3#post-640071 and following) as the basics.

Step 1: sand down the groove until smooth. I didn't have a dowel rod laying around as suggested, but a fat-handled screw driver works almost as well. After a few sessions with the various sandpapers and some Naphtha cleaning, it's smooth and feels ready to be built back up.

Step 2: fill in groove with wood putty. This is a step that requires finesse and artistry, things not associated with me. Nonetheless, I persist. I don't try to fill it back up to level, which I'm worried will look too fake, but I progressively add layers so that becomes a shallow smooth groove. I sand a few times and add more putty until I'm satisfied.

Step 3: color the wood putty. This is the next area that makes me concerned. The guide recommends masking off the area and painting in the wood layers. I'm not sure what this means or how to do it, so I'm just going to try staining until I get approximately the right color. I started with the lightest stain at Home Depot, Natural. The wood picture matches the playfield, especially under the apron where it hasn't discolored. However, with wood putty it really doesn't change the color at all, so I need to go darker. I end up picking a redder stain, partially because there wasn't a very yellow stain available. After a lot of brushing, and then cleaning, and brushing, and cleaning, I end up with a decent result. The shooter lane looks mostly consistent, a shade darker than the rest of the playfield, but not extremely noticeable and mostly blended together. The other problem I had was trying to sand and clean after the staining. If I sand at all, the stained putty is removed, leaving unstained putty. So after the final staining, I try not to sand at all.

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