1949 United Mfg "Utah" pinball - loud buzzing

(Topic ID: 140462)

1949 United Mfg "Utah" pinball - loud buzzing

By PinballFever

3 years ago

Topic Stats

  • 11 posts
  • 4 Pinsiders participating
  • Latest reply 3 years ago by PinballFever
  • Topic is favorited by 1 Pinsider


Linked Games

No games have been linked to this topic.

    Topic Gallery

    There have been 4 images uploaded to this topic. (View topic image gallery).


    #1 3 years ago

    More information about the game here. https://pinside.com/pinball/forum/topic/40s-united-pinball-machine-cleaning-question

    There is no schematic for this game so I'm asking your help with troubleshooting this issue here.


    The game used to complete the reset sequence but now it stops with the 900,000 and 90,000 lights lit.

    The 10,000 Step Up Unit is staying energized causing the loud buzzing but I'm not sure what's keeping it energized? What should I look for?

    Thanks in advance,


    #2 3 years ago

    Stuck closed switch on the playfield.

    #3 3 years ago
    Quoted from KenLayton:

    Stuck closed switch on the playfield.

    That was my thinking too.

    It started after I removed the 10 passive bumpers for cleaning and new rubbers then put them back in.

    Will check them for closed switch after work today.


    #4 3 years ago

    On my Singapore, occasionally I'd push in the slide for a reset and the 10,000 point stepper would buzz real loud as if something in the reset wasn't completing. It would buzz until I killed the power. I'd power the game up and it would be alright until I tried to reset again. Intermittently.
    That's the primary reason I took the time to reverse-engineer the schematic and process sequences. If I don't know how it is supposed to work then it can be more difficult to diagnose problems.

    In my case, the home position switch on the score motor wasn't adjusted correctly. There are a few switches on the home position switch stack, one controls where the motor stops. This is a note I made on my diagrams:
    Score Motor Switch Adjustment.png

    If that helps any.

    #5 3 years ago

    The diagram I posted should say "B to change state before A opens"
    In my case, "B" controlled the 10,000 point solenoid that was buzzing. "A" controlled the score motor.

    The problem would happen when switch A opened first that caused the score motor to stop turning. Sometimes there wouldn't be enough drift in the cam and switch B wouldn't change state, causing the solenoid to stay on and buzz.

    #6 3 years ago


    Thanks for the tip. Someday soon I'd like to buy the schematic that you made for your game.


    It's FIXED and is what I thought it would be. Ken was correct. The new rubbers were tighter pushing in one or two passive bumper switches.

    I had to use the Harbor Freight head magnifying glasses with lights to be able to see them well enough with my aging eyes so I could gap them correctly with the switch adjuster.

    Thanks guys,

    Harbor Freight head magnifying glasses with lights

    Passive bumper switch

    #7 3 years ago

    Here's a shameless plug:
    You might be interested in this thread:

    I am sure some circuits will be different but there are probably many similarities.

    #8 3 years ago

    Steve, is that smaller/larger gap design a quirk of this era or do you know if that is present on newer machines? That would be a killer to diagnose if you weren't aware of it!

    #9 3 years ago

    Thanks Steve. I plan to order one soon but would like a printed paper copy similiar to a real schematic if possible?

    I marked the topic as Solved.


    #10 3 years ago

    I am not sure about the other games.
    You can always take the file to a Walmart (etc) and make a hard copy for yourself.

    #11 3 years ago
    Quoted from SteveFury:

    You can always take the file to a Walmart (etc) and make a hard copy for yourself.

    I'll paypal you for the schematic when I get the next paycheck.


    Promoted items from the Pinside Marketplace
    $ 27.99
    Lighting - Interactive
    Lee's Parts
    $ 199.99
    $ 10.00
    Third Coast Pinball
    $ 84.95
    Cabinet - Shooter Rods
    Super Skill Shot Shop
    From: $ 9.99
    Matt's Basement Arcade
    From: $ 175.00
    Gameroom - Decorations
    Pinball Photos
    $ 60.00
    Cabinet - Shooter Rods
    Mods for your pinballs
    From: $ 99.99
    Cabinet - Other
    Lighted Pinball Mods
    From: $ 218.00
    $ 109.95
    Cabinet - Armor And Blades
    $ 87.95
    Cabinet - Shooter Rods
    Super Skill Shot Shop
    From: $ 99.99
    Cabinet - Other
    Lighted Pinball Mods
    $ 5.00
    Playfield - Decals
    Doc's Pinball Shop
    $ 49.99
    Playfield - Toys/Add-ons
    Lighted Pinball Mods
    From: $ 42.00
    Cabinet - Shooter Rods
    ModFather Pinball Mods
    $ 36.99
    Lighting - Interactive
    Lee's Parts
    $ 14.95
    Playfield - Toys/Add-ons
    From: $ 99.99
    $ 48.00
    Cabinet - Other
    ModFather Pinball Mods
    $ 117.00
    Playfield - Toys/Add-ons
    The MOD Couple
    $ 99.95
    Cabinet Parts
    Merf's Pins
    $ 19.99
    Playfield - Plastics
    Docquest Pinball Mods
    $ 10.00
    Apparel - Unisex
    Lee's Parts
    $ 7,499.00
    Pinball Machine
    Flip N Out Pinball

    Hey there! Got a moment?

    Great to see you're enjoying Pinside! Did you know Pinside is able to run thanks to donations from our visitors? Please donate to Pinside, support the site and get anext to your username to show for it! Donate to Pinside