(Topic ID: 113021)

Do EM pop bumper coils weaken with age and use?

By BlackCatBone

9 years ago



Topic Stats

  • 9 posts
  • 7 Pinsiders participating
  • Latest reply 9 years ago by wayout440
  • No one calls this topic a favorite

You

Linked Games

No games have been linked to this topic.

    #1 9 years ago

    Yes, this question may be as naive as the title suggests. Having pumped half my youthful fortune into countless 1960s EM games with sluggish pop bumpers, I always assumed the answer was yes. However, after replacing the coil sleeves and plungers in my 1965 Gottlieb with factory-original coils, I was surprised to discover that the bumpers were every bit as strong as when I played the same game when new, in 1965. So that leads back to the question - do coils ever need to be replaced, as long as they have not burned out?

    Thanks!

    #2 9 years ago

    No the coils don't really weaken. The sleeves, springs, and mechanical mechs wear. Rebuilding those and you should be as good as new

    #3 9 years ago
    Quoted from BlackCatBone:

    Yes, this question may be as naive as the title suggests. Having pumped half my youthful fortune into countless 1960s EM games with sluggish pop bumpers, I always assumed the answer was yes. However, after replacing the coil sleeves and plungers in my 1965 Gottlieb with factory-original coils, I was surprised to discover that the bumpers were every bit as strong as when I played the same game when new, in 1965. So that leads back to the question - do coils ever need to be replaced, as long as they have not burned out?
    Thanks!

    nope, never have to be replaced... solenoid coils don't "wear out"... the only time you should ever have to replace a solenoid coil is if it was damaged by being locked on and overheating, or by physically damaging it yourself (done that a few times trying to remove old metal sleeves)...

    coils that are used for "lock relays" (coin lockouts, hold relays, etc.) *may* eventually "burn out" due to their constant duty cycle, but it is not overly common... they may buzz like hell, but they generally still work... the only one that i've had to replace literally came apart in my hands, it was so burnt...

    #4 9 years ago
    Quoted from ccotenj:

    nope, never have to be replaced... solenoid coils don't "wear out"... the only time you should ever have to replace a solenoid coil is if it was damaged by being locked on and overheating, or by physically damaging it yourself (done that a few times trying to remove old metal sleeves)...
    coils that are used for "lock relays" (coin lockouts, hold relays, etc.) *may* eventually "burn out" due to their constant duty cycle, but it is not overly common... they may buzz like hell, but they generally still work... the only one that i've had to replace literally came apart in my hands, it was so burnt...

    Just read this.

    So, putting new coils in hold relays etc should reduce buzzing?

    #5 9 years ago

    related.. power supply can get weak several ways, resistance up, capacitance down, etc.
    global (everywhere) or not can depend on how many outputs the supply has.

    #6 9 years ago
    Quoted from Shapeshifter:

    Just read this.
    So, putting new coils in hold relays etc should reduce buzzing?

    It can, but I have found that new coils don't always solve the problem. Sometimes it's the spring tension on the ativator plate. Like Ccotenj said, I had to replace the original hold coil that just fell apart in my hands when I was trying to move it around to get it quiet. Put the new coil in, still buzzed. Messed around with the spring a bit and eventually got it to quiet down.

    #7 9 years ago
    Quoted from zizzlemeplease:

    related.. power supply can get weak several ways, resistance up, capacitance down, etc.
    global (everywhere) or not can depend on how many outputs the supply has.

    not an issue with em's....

    Quoted from Shapeshifter:

    Just read this.
    So, putting new coils in hold relays etc should reduce buzzing?

    see below... sometimes yes, but other times, you also need to mess with the whole thing, possibly replace the armature, and so on...

    Quoted from wayout440:

    It can, but I have found that new coils don't always solve the problem. Sometimes it's the spring tension on the ativator plate. Like Ccotenj said, I had to replace the original hold coil that just fell apart in my hands when I was trying to move it around to get it quiet. Put the new coil in, still buzzed. Messed around with the spring a bit and eventually got it to quiet down.

    #8 9 years ago

    Let me pipe in here: the MAIN reason why EM pop bumpers (and flippers) can weaken over time is due to dirty/misaligned contacts on the leaf switches. Why? Because the full current for the power stroke goes through the pop activation switch. That's the switch that is closed when the skirt rod sticking thru the playfield moves the small 'cup' underneath. (For flippers, both the flipper button switches and the EOS switches on the flipper mech conduct the full coil current.) In contrast, the corresponding switches on modern games just send a logic signal to the CPU at low voltage/current.

    Because these leaf switches carry a higher current/voltage, they can also more easily arc or pit a bit. The best way to clean them is to first properly gap and ALIGN the contacts (they should be FLAT against each other when the switch closes). Then clean them by inserting a folded new dollar bill (or emery paper--fine sandpaper--that is rough on both sides when folded over) between the contacts, pinch them together with your fingers, and pull the bill/paper out from between the contacts. This will clean them and the pressure will help to make the contacts flat and aligned for good contact.

    Besides the dirty switches, of course the mechanisms (coil plungers, sleeves, etc.) should be clean and smooth, and springs should be properly adjusted.

    #9 9 years ago
    Quoted from StevenP:

    Let me pipe in here: the MAIN reason why EM pop bumpers (and flippers) can weaken over time is due to dirty/misaligned contacts on the leaf switches. Why? Because the full current for the power stroke goes through the pop activation switch. That's the switch that is closed when the skirt rod sticking thru the playfield moves the small 'cup' underneath. (For flippers, both the flipper button switches and the EOS switches on the flipper mech conduct the full coil current.) In contrast, the corresponding switches on modern games just send a logic signal to the CPU at low voltage/current.
    Because these leaf switches carry a higher current/voltage, they can also more easily arc or pit a bit. The best way to clean them is to first properly gap and ALIGN the contacts (they should be FLAT against each other when the switch closes). Then clean them by inserting a folded new dollar bill (or emery paper--fine sandpaper--that is rough on both sides when folded over) between the contacts, pinch them together with your fingers, and pull the bill/paper out from between the contacts. This will clean them and the pressure will help to make the contacts flat and aligned for good contact.
    Besides the dirty switches, of course the mechanisms (coil plungers, sleeves, etc.) should be clean and smooth, and springs should be properly adjusted.

    This is true about the high current leaf switches (large silver or tungsten contacts) in general, I will just point out that on my Gottlieb woodrail, the high current leaf switches for the pop coils are at relays under the playfield, and not the spoon activated switches. The spoon activated switches are smaller contacts and cause the relay coils to turn on. I can fire the pops by manually moving the activator plates on these relays.

    Your cleaning suggestions are good, it's just that on these games the high current leaf switches are located in a different place

    Reply

    Wanna join the discussion? Please sign in to reply to this topic.

    Hey there! Welcome to Pinside!

    Donate to Pinside

    Great to see you're enjoying Pinside! Did you know Pinside is able to run without any 3rd-party banners or ads, thanks to the support from our visitors? Please consider a donation to Pinside and get anext to your username to show for it! Or better yet, subscribe to Pinside+!


    This page was printed from and we tried optimising it for printing. Some page elements may have been deliberately hidden.

    Scan the QR code on the left to jump to the URL this document was printed from.