By Todd "PinTed" Andersen

The following is a list of ten things your mother taught you, but never told you applied to rebuilding pinball flippers. This is something I had to learn the hard way. I learned it on the street - while working on a coin-op route.

1) Safety First!

This rule is so important; it had to be listed first! Perform all repairs with the game turned off or even unplugged. Only after you have completed your repair(s), power up the game and use the internal diagnostics or game play to verify that the game is now fixed.

2) A KISS Usually Makes It Better

KISS = Keep It Simple Silly. It is easier and far better to look for the simple to check and easy to find things before you start ripping into your circuit boards. Look before you cross the street to board repair.

Always look for broken: brackets, diodes, and wires on the assembly you are having trouble with.

First look for shorted brackets or diodes on the assembly you are having trouble with. Verify that the assembly will not allow the coil's lugs to short out against something nearby.

The lug of the coil was intermittently shorting against the playfield rail until Lloyd isolated the lug. (LTG)

After first looking at the suspect assembly, check the voltage with a meter. Then, if the incorrect voltage is found, depower, pull and electrically check the associated fuse.

Lastly, use your meter to verify that the suspect assembly's wiring is complete over to an associated assembly and/or back to its board.

Only now have you limited the possibilities of a problem to the associated circuit board.

3) Your Eyes Are Your Best Feature

L-O-O-K first, before you begin any troubleshooting or work on a pinball machine.

Look for tell-tail signs such as excessive: dirt, dust, or lubrication.

Look for problems such a: binding, broken, cracked, crooked, loose or incorrect parts and/or assemblies.

Notice the wear on the bottom of the link. (LTG)
The complete spring on the left, the broken spring on the right. (LTG)

4) Get In Touch With Your Feelings

Feel for problems such a: binding, broken, cracked, crooked, or loose parts and/or assemblies.

Pictured is a loose wire. (LTG)

Yes, this open was “rigged” just to get this picture, but it's still a good example.

Links can be gently twisted to expose cracks or fatigue. This technique is especially useful on flipper links.

Notice the crack on the left side of the link. (LTG)

I don't remember how many of Lloyd's games I had to look in before I found this. And even then, this crack was not visible until the link was flexed.

Push the plunger at a 45° angle when checking for drag due to a mushroomed plunger end. Push four points around the plunger. If you are not sure if you feel drag/resistance, disassemble the flipper assembly and start over again with a visual inspection.

What a drag.

The plunger on the left is new. The end of plunger on the right has flattened so much that it has just started to mushroom and scrape against the coil sleeve.

The stationary parts of every assembly should be tight. There should be no play or slop.

5) You Can Keep It Together

Use the hardware holding assemblies together to your advantage. Finding a loose bracket is one thing, common but not necessarily easy to find. The steps above should help. Once a loose bracket is found, first verify that the assembly is merely loose. If verified, first loosen the associated screws one full turn. I know this sound counterintuitive, but it is useful. Next, seat the bracket with just hand force. The first screw to retighten is on the corner of the bracket that will allow the bracket to spin into the assembly as the screw turns.

Yes, yes another rigged picture. But, you get the point don't you? (LTG)

If the spin technique does not work, you probably missed the fact that either one piece of the assembly is bent/warped or it is broken/cracked. In such cases, a rebuild is necessary.

6) Always Wear A Rubber

Always put a new rubber on the tip of your flipper crank. I recommend two walled polychloroprene ( neoprene ) rubber for several reasons. Neoprene is tougher than other rubber but elastic at the same time. Two walled shrink-tubing stays put once properly applied. In use, this tubing is resistant to: sunlight, water, many solvents, and even some petroleum products. There is also the advantage in that its two walls provide a better composite dielectric material; therefore better isolation from electricity = greater safety for the player.

7) The Golden Rule

I gave this rule in a previous article. This is the golden rule for flipper rebuilds. It is, 1/8 - inch (0.125” or about 3 mm). There should be 1/8 - inch of spacing between the flipper bushing and the flipper pawl. And, there should also be a 1/8 - inch space between the individual leaves of the EOS switch when the flipper pawl crank breaks the contacts at full stroke. And there should be less than 1/8 – inch of play/slop in a flipper link.

Pictured below, courtesy of LTG, is the proper way to check for slop of a flipper link. First fully actuate only the metal plunger with your finger. Listen and feel for the plunger to hit and seat against the coil stop. No not use any other part of the flipper for this test! If the plunger does not seat, you need not go any farther; it is time for a rebuild. If the plunger does seat, it is time to check for excessive play in the flipper link. Keep the plunger firmly held against the stop. Then, push down and pull up on the pawl. If you can easily move the link more than 1/8 – inch, it is time for a rebuild.

If your active inspection proves the flipper parts to be sound, it is time to look at the leaves of the End of Stroke (EOS) switch. If your EOS is normally closed, the spacing between the now open tungsten contact points should be 1/8 – inch. If your EOS is normally open, the gold points should start 1/8 – inch apart and should have traveled at least another 1/8 – inch after the contacts first closed. With either type of EOS switch, there should be no contact with the cam on the pawl when the flipper is at rest. Both EOS switches should have at least 1/8 – inch travel at the very end of the flipper stroke. The starting and finishing requirements of the EOS allow the contact to burnish one-another, thusly self-cleaning the points. Slowly actuate only the metal plunger to verify correct and proper operation of either type of EOS. If you can verify that the plunger assembly is actuating properly, but if the EOS is not working properly, it is time to adjust the stationary blade of the EOS.

You must verify that the EOS is tight before you can adjust it. The proper way to tighten a switch stack is to start with the screw closest to the contacts first. Then tighten the other screw. Because this tightening my bring the spacing of your EOS back into spec, go back and re-actuate, again, only the plunger. If the EOS is still out of spec, stat by adjusting the stationary blade as needed. Then, and only if needed, adjust the moving blade of the EOS.

8) Clean Your Area

Clean Your Parts

Sometimes you must remove the black dust (carbon) that seems to coat every assembly before you can see the problem. Removal of the dust will allow you to look for otherwise obscured problems such as: breaks, cracks, and ware marks. Removal of the abrasive dust will also help your pinball last longer.

The excessive wear mark on this old assembly is easier to see now that the grime has been removed. (LTG)

Keep Your Area Clean.

Something like a PinPan , which JoePinball sells, can be very useful in keeping parts organized and in keeping them from getting lost in the machine.

Parts and tools are kept close at hand.

Find A Good Place

Do as Bryan (AKA: Mr. Pin-Footie) says and does - put parts on a different table. That way you won't have to waste time looking for a part which you dropped or misplaced.

Mise en place , a place for everything and everything in its place.

9) Try Your Best, And Don't Be Ashamed To Ask For Help

Perfect practice makes perfect flipper assemblies. So, start using these rules to rebuild your flippers today. If you have trouble rebuilding your flippers, there are several resources available to you. Don't be afraid to use your resources.

In Game

  • Game Assemblies
  • Learn how the assembly works before you take it apart.
  • Look for a similar or identical assembly right next to the one you are working on.

Game Manual

  • Don't forget to look in your manual. It you don't have a manual for your game;
    buy one!

On Line

  • Pinball Collector Register
    Link: (http://www.xmission.com/~daina/tpcr/)
    This is a searchable site that can help you find other pin-heads in you area. Some of these people may be good resources.
  • Pinball News Group : Rec.Games.Pinball (RGP)
    Link: (http://groups.google.com/group/rec.games.pinball)
    This group is devoted to pinball. All pinball questions are welcome. Responses may be posted on the group or via private email.
  • Pinball Repair Guide
    Link: (http://www.marvin3m.com/fix.htm)
    This is a very extensive pinball repair site. The site covers multiple manufacturers and eras of pinball machines.
  • Pinball Tip Guide
    Link: (http://www.xmission.com/~daina/tips/pub/tip_archive.html)
    This is a very extensive, listed, and searchable pinball tips site.

10) Tips-n-Tricks

Get In There, Tiger!

A 1/4 – inch, right angle driver is very useful when working in confined/small spaces. For this very same reason, hemostats are also very useful tools for use in pinball machines.

Try A Little Harder

A 11/32 – inch nut driver can be used to remove an old coil sleeve. Gently tap the driver with a small hammer to chase out the old sleeve.

Take A Seat

Parts can be seated or tightened by gently tapping them with a small hammer. This can, and even should, be done with a new coil sleeve. But, if a new coil sleeve won't fit when very gently tapped with a hammer, try another sleeve. Due to standard manufacturing variation such as differences in: outside diameter, part rigidity, and wall thickness, one sleeve may fit when a seemingly identical sleeve did not. If the different sleeve still doesn't fit, it's time to change the coil.

Keep Still

Whenever possible, position flipper coils so that the lugs are in the center of flipper assembly rather than towards the stop bracket. This will lessen the vibration going to the attaching points and will help with the longevity of the connections to the diodes and wires.

Remember, “Mother knows best, even about rebuilding flippers.” Now go call your mother.


Picture This

With the exception of the pictures from Bryan Kelly and JoePinball ; most pictures are courtesy of and SS Billiards.
All un-notated pictures are courtesy of , but property of Pinball News . All pictures notated (LTG) are courtesy and property of SS Billiards. The pictures from LTG are used with permission.


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