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  • TECH: Solenoid plunger has to be moved (just a little) to fire reliably

    From Tim Kuo@21:1/5 to All on Tue Feb 14 19:16:09 2023
    My Twilight Zone has a solenoid that won't "stroke" reliably unless the plunger is pressed in just a little, just a tiny bit. So my "just get it working" solution is to put in a small plastic washer on top of the plunger, to keep the plunger from
    extending too far. Which is working 100%.

    But I'd like to understand what's going on. This is the solenoid for the TZ cage/bridge diverter. As far as I can tell, there's no EOS switch or anything like that.

    When the solenoid doesn't plunge, you can still hear a hum, so it seems like there's power going to the solenoid.

    Is there something internal to the solenoid that keeps it from moving if the plunger isn't in exactly the right position? The plunger is not binding, and pressing the plunger in (by just the thickness of a washer) makes the solenoid work flawlessly...

    TIA!

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  • From John Robertson@21:1/5 to Tim Kuo on Wed Feb 15 06:45:12 2023
    On 2023/02/14 7:16 p.m., Tim Kuo wrote:
    My Twilight Zone has a solenoid that won't "stroke" reliably unless the plunger is pressed in just a little, just a tiny bit. So my "just get it working" solution is to put in a small plastic washer on top of the plunger, to keep the plunger from
    extending too far. Which is working 100%.

    But I'd like to understand what's going on. This is the solenoid for the TZ cage/bridge diverter. As far as I can tell, there's no EOS switch or anything like that.

    When the solenoid doesn't plunge, you can still hear a hum, so it seems like there's power going to the solenoid.

    Is there something internal to the solenoid that keeps it from moving if the plunger isn't in exactly the right position? The plunger is not binding, and pressing the plunger in (by just the thickness of a washer) makes the solenoid work flawlessly...

    TIA!

    Which plunger assembly?

    Does the plunger look like it is original? A plunger that is slightly
    too short could easily account for the problem.

    Is there a rubber bumper at the end where the plunger and link rest?
    Perhaps it is missing or worn down...

    You can download the manual from https://ipdb.org and it shows most
    mechanical parts used in the game.

    John :-#)#
    --
    (Please post followups or tech inquiries to the USENET newsgroup)
    John's Jukes Ltd.
    #7 - 3979 Marine Way, Burnaby, BC, Canada V5J 5E3
    (604)872-5757 (Pinballs, Jukes, Video Games)
    www.flippers.com
    "Old pinballers never die, they just flip out."

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From Tim Kuo@21:1/5 to All on Wed Feb 15 08:05:17 2023
    Which plunger assembly?

    It's the solenoid for the cage/bridge diverter on a Twilight Zone.

    Does the plunger look like it is original? A plunger that is slightly
    too short could easily account for the problem.

    As far as I can tell, everything is original.

    Is there a rubber bumper at the end where the plunger and link rest?
    Perhaps it is missing or worn down...

    The manual calls out a washer (around the wire to the cage) between the end of the plunger
    and the metal barcket/plate "above" the solenoid. I didn't see a washer there when I went
    to replace the wire, and it was totally by luck that I figured out that slightly pressing on the
    plunger made the solenoid "plunge" reliably.

    Any Idea why the initial position of the plunger would make it more/less reliable?
    I could see where it might decrease plunge strength slightly, but in this case it's "all or nothing"

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    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From John Robertson@21:1/5 to Tim Kuo on Wed Feb 15 12:40:40 2023
    On 2023/02/15 8:05 a.m., Tim Kuo wrote:
    Which plunger assembly?

    It's the solenoid for the cage/bridge diverter on a Twilight Zone.

    Does the plunger look like it is original? A plunger that is slightly
    too short could easily account for the problem.

    As far as I can tell, everything is original.

    Is there a rubber bumper at the end where the plunger and link rest?
    Perhaps it is missing or worn down...

    The manual calls out a washer (around the wire to the cage) between the end of the plunger
    and the metal barcket/plate "above" the solenoid. I didn't see a washer there when I went
    to replace the wire, and it was totally by luck that I figured out that slightly pressing on the
    plunger made the solenoid "plunge" reliably.

    Any Idea why the initial position of the plunger would make it more/less reliable?
    I could see where it might decrease plunge strength slightly, but in this case it's "all or nothing"

    Yeah, I see the washer - item 13 on page 2-26 of the Bally - TZ manual (ipdb.org) parts section. I assume it was added so the plunger would be
    far enough in the coil so it would get a good pull.

    Plungers have to be a minimum amount inside the coil for fast action is possible. Flippers have different types of plunger/lint stops, either
    metal or rubber. As these wear you loose flipper strength as the plunger
    moves a bit further out of the coil...

    So add a washer or two on the wire where #13 shows and you should be good.

    John :-#)#

    --
    (Please post followups or tech inquiries to the USENET newsgroup)
    John's Jukes Ltd.
    #7 - 3979 Marine Way, Burnaby, BC, Canada V5J 5E3
    (604)872-5757 (Pinballs, Jukes, Video Games)
    www.flippers.com
    "Old pinballers never die, they just flip out."

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)