(Topic ID: 241769)

SDB in Bally Black Jack shows 2.25v for 5v test points


By Mathazar

6 months ago



Topic Stats

  • 5 posts
  • 3 Pinsiders participating
  • Latest reply 6 months ago by wayout440
  • Topic is favorited by 1 Pinsider

You

Linked Games

No games have been linked to this topic.

    #1 6 months ago

    I picked up a non-working 1978 Bally Black Jack project a few weeks ago and I'm finally getting around to it this weekend. Power on and GI comes on but MPU won't boot (solid LED). Disconnected all boards and started with the power supply. Fuses are intact and at the correct values, and all test points on the rectifier board show proper DC and AC voltages.

    I now have J3 on the rectifier board and J3 on the SDB connected. TP1 and TP3 on the SDB show only 2.2v instead of 5v. All other test points on the SDB show their correct values. Figure this will be the starting point of the repair journey. I've re-pinned all of the connectors on the SDB and rectifier, but no help.

    I'm looking for guidance on what to check next, hopefully something specific to do to hone in on the low 5v circuit (vs. shotgunning and replacing a bunch of parts...I'm not very handy yet with a soldering iron on a PCB). Note: The SDB in this machine is a Stern SDU-100 Revision A (blue masking). I don't have another spare SDB at the moment to stick in there and see if it progresses any further.

    Thanx in advance for any guidance...

    #2 6 months ago

    Start by replacing the +5VDC filter cap. Filter caps are designed to last about 10 years. So that means ALL Bally games from 1977 to 1985 should have their C23 +5 volt filter capacitor replaced. You should also perform the recommended upgrades on the tech pages:

    2c. Before Turning the Game On: Upgrading the Voltage Regulator/Solenoid Driver Board. http://techniek.flipperwinkel.nl/ballyss/rep/index1.htm#cap

    #3 6 months ago

    wayout440 - I've replaced C23 and performed the ground and +5 mods as outlined in the link you provided, but I'm still getting only 2.2VDC at the 5VDC test points TP1 and TP3. What's next....replace all the caps I'm afraid?

    #4 6 months ago

    If you verified the input to the voltage regulator is correct and the ground screw is tight and connecting the regulator case to ground, it would appear the regulator is defective.

    #5 6 months ago
    Quoted from MrBally:

    If you verified the input to the voltage regulator is correct and the ground screw is tight and connecting the regulator case to ground, it would appear the regulator is defective.

    Second this.

    Promoted items from the Pinside Marketplace
    From: $ 40.00
    Lighting - Interactive
    Professor Pinball
    $ 74.00
    Cabinet - Armor And Blades
    Id Rather Play Pinball
    From: $ 24.00
    $ 100.00
    $ 85.00
    Playfield - Toys/Add-ons
    Lermods
    € 6.50
    Flipper Parts
    Buthamburg
    $ 26.50
    Playfield - Toys/Add-ons
    The MOD Couple
    From: $ 9.99
    Eproms
    Matt's Basement Arcade
    From: $ 42.00
    Cabinet - Shooter Rods
    ModFather Pinball Mods
    From: $ 25.00
    Gameroom - Decorations
    Gameroom Mods
    $ 10,999.00
    $ 6.00
    Cabinet - Other
    Siegecraft Electronics
    From: $ 42.00
    Cabinet - Shooter Rods
    ModFather Pinball Mods
    $ 25.00
    Cabinet - Other
    Filament Printing
    $ 315.00
    Playfield - Toys/Add-ons
    liorillusion
    $ 78.00
    Playfield - Toys/Add-ons
    ModFather Pinball Mods
    From: $ 175.00
    Gameroom - Decorations
    Pinball Photos
    $ 109.99
    From: $ 99.99
    Cabinet - Other
    Lighted Pinball Mods
    From: $ 9.99
    Eproms
    Matt's Basement Arcade
    $ 399.99
    Cabinet - Toppers
    Great American Pinball
    $ 25.00
    Cabinet - Other
    Filament Printing
    € 159.00
    Cabinet - Toppers
    FlipperLED

    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