• Re: Williams System 7 blows solenoid fuse on poweron--how to troubleshoot?

    From Tim Otis@timotis60@gmail.com to rec.games.pinball on Friday, July 03, 2020 06:03:23
    From Newsgroup: rec.games.pinball

    On Tuesday, September 16, 2008 at 2:33:42 PM UTC-4, firepower wrote:
    On 16 Sep, 17:29, Ed.Toro...@gmail.com wrote:

    I turned on my Williams Barracora the other day after it had been off
    for a few weeks.

    The score was confused and it obviously wasn't starting up correctly,
    so I turned it off and restarted. At that point, the high score and
    credits were displayed properly, and I could press the start button to start a game, with all the usual melodies playing. However, no reset
    of drop targets, and no ball to launch.

    Well, the 2.5A slow-blow fuse for solenoids was blown. I replaced it,
    and it blew again when I turned on the main power switch.  I cheated
    (oh oh) and put in a 7.5A fuse, and it blew when I turned the game on
    as well.

    1)  There's a way big overload or short somewhere
    2)  The game worked properly last time it was on
    3)  I don't recall opening the game up to do anything

    Any hints or suggestions on how to proceed?



    You have a dead short on one of the solenoids (or solenoid
    transistors). Probably not a wiring fault if you haven't changed

    You can set a multimeter to Buzz and WITHOUT turning on the game touch
    the centre tab of each of the 22 solenoid transistors on the left of
    the driver board.
    The ground wire should go to the cabinet braid wire, or any ground in
    the backbox. The transitors are the big ones on the Left of the
    driver board and will be TIP102 or TIP120 's If you get a buzz (or
    near Zero ohms reading) that is the one that is shorted. Fit that
    coil or transistor, put in a new 2.5A Timed fuse and you are back to flipping. Try that and see how you get on.

    After that - head on over to the Marvin guides at www.marvin3m.com/fix
    you want the System 3 to 7 repair gude, it's all in there.

    I am trying to repair a Firepower PB machine using http://www.firepowerpinball.com/downloads/DriverBoard.pdf I have discovered that my 2,5 amp fuse does not blow by unplugging 2J12. I have checked the solenoids I believe are associated with it and they all have about 4 ohms. Could you tell me why on the diagram it says solenoid 22/special solenoid 6 left kicker Q12/22? Are there 2 different solenoids and two different transistors to check? I have found solenoid 22 by the playfield diagram but not sure where special solenoid 6 is. When the plug is not attached to the driver board the fuse does not blow but after re-attaching it the fuse blows as soon as power is applied again. Trying to figure out what I am missing with the 2 solenoid numbers on each line plus the 2 transistor numbers
    --- Synchronet 3.18a-Win32 NewsLink 1.113