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This page covers pop bumpers found on early solid state Bally pinball machines (Power Play, Mata Hari, Evel Knievel, etc.). Newer Bally pinball machines may use these type of pop bumpers too, I don't know. If I learn about them, I'll update this page. I'll also add sections to the page on how a pop bumper works and adjusting the switch, later.


Removing a Pop Bumper

Removing a pop bumper from a Bally pinball machine is easy, it just takes a little work.
  1. Remove the pop bumper's cap by removing the two small screws (picture)
  2. Remove the lamp by twisting and pulling it (picture)
  3. Remove the two phillips head screws inside the pop bumper body (picture)
  4. Remove the two lock nuts on the pop ring posts (attached to the plate on the solenoid plunger) (picture)
  5. Locate the metal straps (wires), one on each side, for the lamp - don't cut these or they'll be too short when you reinstall (picture)
  6. Using a small screwdriver, carefully pry up, but do not remove the staples that hold both "wires" down or you'll play hell trying to get it back in (picture)
  7. Unsolder the power wires from the lamp "wire" being careful not to melt the insulation of other wires (picture)
  8. Using a small screwdriver again, lift up on the lamp "wire" to slide it out from under the staple (picture)
  9. With small pliers, grab the lamp socket and pull it out. If it sticks, there may be excess solder on the lamp socket "wires", remove it (picture)
  10. Now just lift the rest of the pop bumper assembly off the playfield (picture)
  11. With a small screwdriver, very carefully pry off the base plate from the pop bumper body - easy does it or it'll break (picture)
  12. And there you have it, in all it's glory (picture)


Removing the coil and switch assemblies

Since you're already in there anyway, you might as well remove the coil and switch assemblies and give them a good cleaning (that black coil dust gets everywhere). While you're in there, replace the coil sleeve too, they're cheap and will help the pop bumper do a better job.
  1. Remove the coil bracket by removing the two screws on the back of the pop bumper assembly (picture)
  2. Lift the mounting plate up into the coil, being careful of the plastic switch spoon below it (picture)
  3. Now lower the coil and it's bracket until the coil is free of the stop, then slide the whole mess out (picture)
  4. Remove the coil plunger and all the stuff on it from the coil, remember which parts go where for later (picture)
  5. Here's all the parts you just removed, clean them all up (I used acetone on a rag) (picture)
  6. While you're at it, remove the coil sleeve and put in a new one (or clean up the old one if possible) (picture)
  7. Here's what the pop bumper switch assembly looks like - look at all that coil dust (yeech) (picture)
  8. Remove the switch assembly by removing the screws holding the mounting bracket to the playfield (picture)
  9. Clean it up real good too w/ a rag and some Novus #2 - be careful, the plastic spoon thing breaks real easy (picture)
  10. Reassemble the parts on the coil plunger, then replace the cleaned up switch and the pop bumper coil

Clean it up!

Before you do anything else, clean the parts of the pop bumper up. The black coil dust is a mess and will get on everything if you don't. I use acetone on a rag to clean up the metal parts, and Novus #2 for the plastic parts.

Look at a before and after picture of the pop bumper skirt

Next, take the metal ring assembly and buff it up. When a pop bumper does it's thing, the ring is pulled down by the solenoid and strikes the ball, sending it flying. If this ring is dirty and messy, it transfers this junk to the ball, which transfers it all over the playfield. You want this ring nice and clean and shiny so it will not scratch up your ball or pass dirt to it.

  1. Buffing up the ring (if you don't have a bench grinder, use fine steel wool, then paste wax)
    If you do have a bench grinder, WEAR FACE PROTECTION!! I've launched these across the room a couple of times (picture)
  2. Before and after, what a difference (your balls and playfield will thank you) (picture)

Put it back together

  1. Start out with the pop bumper body (picture)
  2. Put the nicely buffed ring on it (picture)
  3. Followed by the cleaned-up skirt (picture)
  4. Then the spring (picture)
  5. And finally the base place (you'll see how two "pegs" engage into the body, press them together (picture)

Then put it back on the playfield

Now that you've removed the pop bumper, fixed it, and cleaned it, it's time to put it back on the playfield.
  1. Take the assembly you just made and place it back on the playfield as shown (picture)
  2. Replace the two screws (in the holes with the countersink), but don't tighten them down yet (picture)
  3. Using some pliers, flatten out the lamp socket "wires"
    so they'll insert easier (don't do what I've done and cut them in the plier's wire cutters - twice I've done that!!) (picture)
  4. Replace the lamp socket - this may take some wiggling to get it to go in
    (if it is hard to insert it, check for excess solder and remove it if it's present) (picture)
  5. Now it's almost in, but not quite, we need to go under the playfield in a minute (picture)
  6. Tighten down the two screws - don't over-do it or you'll break the plastic (picture)
  7. Under the playfield, you'll find one "wire" outside the pop bumper bracket and the other inside
    With a small screw driver, push the inside "wire" through the hole in the corner of the bracket (picture)
  8. Now push the lamp socket all the way into the pop bumper body (picture)
  9. Using your pliers, slide the wire back under the staple (picture)
  10. Then drive the staple back in with a blunt tool and a couple taps from a hammer (picture)
  11. Resolder the wire(s) back onto the lamp "wire" (picture)
  12. Then repeat the three previous steps on the other lamp "wire" (picture)
  13. Install a new lamp (picture)
  14. Replace the cap (picture)



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Created 3/15/01 - Last Modified 1/20/07 - Steve Kulpa Mail Icon Nolensville, TN
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