(Topic ID: 148268)

Re-Assembling Passive Bumpers

By Mahoyvan

8 years ago

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  • 5 posts
  • 3 Pinsiders participating
  • Latest reply 8 years ago by MikeO
  • No one calls this topic a favorite


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    #1 8 years ago

    So I've desoldered all of my bumpers to give them a good cleaning and to make room to clean/wax my playfield.

    I made a couple mental notes on how to put them back together, but after taking most of them apart, I noticed that the "rubber on the right" wasn't always the case - My next dirty bumper had the rubber on the left.
    My initial note was that the rubber/plastic on the light socket needed to be to the right when the wafer pointed up...

    Anyways, I know that one side of the socket is Positive, and the other side is Negative, but does it matter when I reinstall them?
    I'm certain that it does matter, so could someone also enlighten me as to what side is what?

    Thanks in advance!

    #2 8 years ago

    It makes no difference. Current will pass through the bulb regardless.

    But the tip on the bumper skirt should point towards the top of the playfield.

    #3 8 years ago

    I definitely remember that the point of the skirt should point up, but wasn't sure about the socket leads. I thought that maybe all the grounds on the sockets had to meet the common ground on the play field.

    Sounds like I'm good to Willie-Nillie go!

    #4 8 years ago

    The bare, common wire isn't ground. It's just the return to the transformer.

    (note that the bulb can still go in the socket either way; there's no orientation.)

    #5 8 years ago

    If you look closely at the lamp socket you will see that one leg is a heavier gauge than the other.

    For a passive bumper it has little to no relevance.

    For a pop bumper the lighter gauge lead gets installed/soldered under the side of the circuit captured by the uncased wire braid that is stapled to the playfield.

    The heavier gauge lead is aligned through the gap in the pop bumper coil bracket to the single lead wire off the playfield harness. The heavier gauge lead is more resistant to shifting position and possibly grounding to the pop bumper coil bracket. On later games they placed a plastic sleeve over this lead between the gap in the pop bumper bracket AND stapled it to the playfield.

    At the factory they probably did install the lighter gauge lead under the wire braid.

    As noted above it makes no difference with a passive bumper because there is no risk of grounding/shorting.


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