(Topic ID: 116085)

Pop bumper design - why 2 materials for yokes?

By RussMyers

9 years ago


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  • 11 posts
  • 8 Pinsiders participating
  • Latest reply 9 years ago by cody_chunn
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    #1 9 years ago

    Pop bumper design - why 2 different materials for yokes?

    One yoke metal, one yoke fiber?

    Why not both steel?

    RussM

    #2 9 years ago

    I'd guess the fiber is to absorb the shock and prevent breakage.

    Ck

    #3 9 years ago

    I ask because I'm fixing a pop bumper where both yokes are broken in half.

    RM

    #4 9 years ago

    the funny part is because the fiber portion has more "give" to it, many times you'll find that the fiber yoke is ok, while the metal one is broken in half.

    my guess is that both materials are used to try to ensure that the part "stays together" once the metal portion is broke. since the machines are supposed to be maintained (just like your car), these are components that should be looked at every so often (probably once a month for heavily routed use, to once every 6 or 12 months for a home use machine).

    #5 9 years ago
    Quoted from j_m_:

    the funny part is because the fiber portion has more "give" to it, many times you'll find that the fiber yoke is ok, while the metal one is broken in half.

    I've never experienced a broken fiber yoke but have had 5-6 metal yokes that have been broken. The RFM I just shopped out had 2 broken metal yokes.

    #6 9 years ago

    Historical precedent - on EM games the normally-closed "hold" switch for the pop bumper relay is actuated by the fiber part of the link (the switch opens when the solenoid plunger is fully retracted into the coil).

    #7 9 years ago

    Replaced all broken parts and tested the pop bumper (BDK) switch working but coil dead.

    Put the meter on it (26-1200) tested at 6 ohms; other 2 coils (and a spare uninstalled coil) at 10-11 ohms. Pulled one wire off: tested open - broken bits had wrecked the coil too.

    Replaced with a spare 26-1200 and we're Green For Go.

    RussM

    #8 9 years ago

    Yeah, I actually had both (mteal/fiber) broke on one of my TZ bumpers. Never knew it until I started taking them apart - it worked fine with both broke.

    #9 9 years ago

    The fiber one is a sometimes used to operate an additional leaf switch blade. So the fiber is an insulator and will not ground the switch it activates.

    #10 9 years ago
    Quoted from KenLayton:

    The fiber one is a sometimes used to operate an additional leaf switch blade. So the fiber is an insulator and will not ground the switch it activates.

    That makes sense.

    RM

    #11 9 years ago

    Note: Pinball Resource sells the Gottlieb version yokes with a bend on one side to prevent them from breaking. They fit modern games and will never break again.

    And that's no yoke!

    huyuk, huyuk.

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