(Topic ID: 201929)

Bally Star Trek solenoids firing during sound test

By Jhn4559

6 years ago


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Topic Stats

  • 11 posts
  • 5 Pinsiders participating
  • Latest reply 6 years ago by barakandl
  • Topic is favorited by 3 Pinsiders

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    #1 6 years ago

    Ok i had previous post and had no sound. I have that fixed but now when the sound plays there are select solenoids that fire. It does it during normal startup and during the test. If i unplug the sound board connector the solenoids still fire.
    If i unplug J4 on the solenoid board the solenoids stop and the sound works normal.
    I cannot seem to figure out what is going on. When i fixed the sound board i had to replace CR3.
    The MPU board is a new alltek board so i do not believe there is an issue there.
    I was advised on here more than likely the connector on sound board but i do not seem to see anything physically wrong
    Any tips / tricks / advice would be helpful.

    Thanks

    #2 6 years ago

    MPU J4, pin 10 is the signal that tells the solenoid board or the sound board to listen to the next command. It goes to J4 pin 7 on the solenoid board and J1 pin 8 on the sound board. If it's low, then the solenoid board fires a solenoid, if it's high then it gives a sound command. Since the sounds are still playing the MPU is operating correctly, so there's probably a problem with the solenoid board or its J4 connector. If it wasn't getting a good connection, that pin would just be floating, which could leave it low enough to still fire solenoids.

    #3 6 years ago

    zacaj - related problem with Bally ST. Saw a post similar to this from 3 years ago but I'm a newbie and didnt catch all the terminology. After tearing down, cleaning, and putting back together the switches are crossed, not firing, and generally weird. Touch one pop bumper the other one fires etc. Any thoughts? Thx

    #4 6 years ago
    Quoted from DocFinlay:

    zacaj - related problem with Bally ST. Saw a post similar to this from 3 years ago but I'm a newbie and didnt catch all the terminology. After tearing down, cleaning, and putting back together the switches are crossed, not firing, and generally weird. Touch one pop bumper the other one fires etc. Any thoughts? Thx

    1. Touch it with an insulated object, like a pencil eraser or something and make sure it still does the same thing. I've had Ballys have weird issues when using your finger.
    2. Document exactly which switches are wrong

    #5 6 years ago

    sounds like the solenoid board select line is shorted low. Check the j4 pin 7 connection on the solenoid board. If that select line is shorted low it will fire coils when trying to make sounds.

    #6 6 years ago

    Thanks for the assistance. I check these connections and do not see anything obvious? I resoldered it to the board with no change. Shorted low does that just mean poor connection usually.? Resistance from front side of pin to back seems fine but not sure if this helps. Wire looks good and clip on the end. Not sure what has happened. I may take a picture and see if anyone sees anytjing obvious with thay J4 pins on the solenoid board

    #7 6 years ago

    With the connector connected and disconnected, measure resistance from the pin on the board to ground.

    Also, can't hurt to repin the connector

    #8 6 years ago

    Thanks all for advice. So far no luck. I measured resistance from pin on solenoid to ground with high resistance. I didnt seem to get any resistance with the connector, connected. I may try that one again. I will attach some pics to see if you see anything obvious?
    One will be of The connector above J4. There is one wierd spot not sure if it is right? They look together but may not supposed to be?

    Thanks

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    #9 6 years ago

    This is the one above j4.

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    #10 6 years ago

    Is that pins 23+24 of J3? If so they should be connected.

    How many ohms is 'high resistance'?

    #11 6 years ago

    Bally went back and forth about isolating the solenoid driver section's ground return. Its fine to have your red circle.

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