Flipper Rebuild Tips

The only reason flippers chatter and bounce in the "up" position with a ball on them is due to excessive play of the plunger in the sleeve, and a corresponding "bounce" of the EOS contacts.

Bally plungers are no longer available, Steve Young of the Pinball Resource provides GTB plungers, which are an adequate replacement. The flipper links are highly prone to wear, as are the pivot pins, so I usually replace the flipper, link, coil sleeve, depending on age and discoloration, the coil, and sometimes the complete flipper arm (the piece that goes between the link and the flipper shaft) in cases where the pin does not "mike" (micrometer) perfectly round.

The next problem area is the plunger stop. The original stops had brass "buttons" on them, but the proved to be expensive and the buttons got loose due to the soft brass. They were soon replaced by stops with steel "buttons", which is probably what you have. After years of use (abuse?) and pounding by the end of the plunger, they become "mushroomed" and magnetized. The best course of action is to use either a heavy metal file (too slow for me) or a grinder and make the end of the "button" flat again. Very carefully remove any "mushrooming" that may be present. Only take off the minimum to make the stop smooth on the face and round in diameter. Then file or grind a small (5 degrees or so) bevel in the end of the stop. This will keep the plunger from having a full face to contact and will extend the period of time before the plunger becomes "sticky" again. If you have access to a demagnetizer, or "degaussing" tool, I would highly reccomend removing residual magnetism from the stops prior to re-assembly.

When operating the plunger assembly by hand, there should be VERY little play in the plunger and link. The flipper bushing is often neglected and can cause excess slop in the linkage, replace them, they're cheap.

Lastly (on the mechanical side) inspect the flipper shaft for excessive wear, a "mike" comes in handy for this as well. Measure the end portion of the shaft that goes through the link lever. Compare the reading with the portion of the shaft that goes through the bushing. If there is appreciable wear, or an "out of round" condition, replace the flipper and shaft with the newer 1 piece units.

Lately, I have gotten in the habit of replacing the return spring with new ones. I never used to, but I have had fewer call-backs on flipper problems since I started replacing the springs. And they're cheap.

The EOS switch will chatter if it is adjusted to just "break" at the very end of the stroke. I usually adjust them to "break" contact about 1/4" before the tip of the flipper comes to the end of its' travel.

There is so much velocity at that point that there is no difference in the "power" of the flipper, and adjusting the switch that way provides no chance that the EOS switch will not open, which would consequentially damage the flipper coil.

The purpose of the EOS switch is to keep the flipper coil from burning up when a player "held" a ball on the flipper in the "up" position. The flipper coil is actually two sets of windings, a "power" set and a "hold" set. The EOS switch is the mechanism to switch between them. When adjusted too tightly, the EOS contacts may not open, causing all the current to go through the "power" set of windings, generating MASSIVE amounts of heat. Usually, the first thing to happen is the coil sleeve melts, generally making the plunger stick. Sometimes you get lucky and can just replace the sleeve and readjust the EOS switch. Mostly, I find that I have to replace the coil as well because the excessive heat has warped the coil core.

I don't cut corners on flipper rebuilds. I find that a few extra dollars spent on parts, and a little extra time devoted to cleanliness goes a long way in keeping them operating trouble-free for a long time.

As a sidelight, all of the above also applies to pre-Fliptronic Williams flippers as well, with the exception that there are choices in flipper links that don't exist in the Bally world.

There are three types of links available for Williams, fibre, nylon, and steel. The steel links will obviously wear the longest, but are a little "stiff" and don't have any "give" whatsoever. They just don't feel right to me. The fibre links are the original equipment and will wear out predictbly. The nylon links seem to be the best comprimise between a good "feel" and improved wear. These are carried by distributors as "Super Links" and are about the same price as the steel ones. Make sure when you order them that you specify NYLON! I have received steel ones by mistake before and had to return them.

Lastly, on switches, I prefer the molded 1 peice switches to the "stacked" kind. Again, they aren't expensive and I usually replace them on a "major" flipper rebuild. The "stacked" switches do allow the replacement of individual blades, but then one contact is old and one is new, and they won't wear at the same rate. An appropriate analogy would be replacing just one tire on you car. Uneven wear is the result and one of the others will become the next failure.

Good Luck,
Allan