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opposite of no strike cycle

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  • opposite of no strike cycle

    hey guys...had a new one on Friday night....a machine stopped seeing strikes(no strike cycle), requiring a reset after strikes...however, Saturday the symptom changed to any 9 count will be seen as a strike, the table comes down, picks up the spare, the strike light comes on, it sets another ten pins with the pin or pins still in the respot cell...seen a seven count do this as well, but mostly nine counts...unplugged the table as Don in Ohio suggested, and the problem is gone...just have to push the reset after strikes....this seems opposite of how the circuit works, so I am perplexed as to how this can happen...I welcome your input and suggestions as always!

  • #2
    It sounds like you have a short to ground in the table wire harness. To understand how this works, refer to the two pictures below. These are from the old stepper schematics and I believe you have ZOT chassis but these should still show how the detection works.

    Figure 1 (filename 8230b) shows an overall view of the table wiring and the sw6 switches. The bottom half of the switch circuit is for pindicators and these are normally open. The top half is for the strike/standing pin detection and these are normally closed. These are the ones we will concentrate on. When no pins are standing, the switches will remain closed and the circuit will show continuity between K and L of the plug. This is a strike indication.

    When a pin is detected the cell switch will open and so the continuity will be broken between K and L. This is an indication of standing pins. This is why your problem goes away when you unplug the table harness. You break the continuity between K and L and so every shot looks like standing pins.

    Now referring to the left side of figure 2 (filename 8230a) you can see what happens. When the table lowers to detect pins, if all the pins are down then the sw6 switches will all be closed and the left side of PR4 will be tied to ground through the path indicated with the dark blue lines. This will energize PR4 as the other half of the relay is constantly hot and a strike cycle will run. If any of the sw6 switches are open because of a standing pin then PR4 can't be tied to ground and so it doesn't energize and no strike cycle runs.

    In your case, it sounds like you had a wire come off and so the continuity between K and L was broken and so no strike would ever be detected as it always looked like a pin was breaking the circuit. Then I suspect the wire eventually made it's way to ground against the table chassis and caused your new symptoms. This could also be an intermittent problem.

    To understand this, look at the switches circled in blue on the right side of figure 2 below. The switches are numbered above them with the pin they detect. These start on the left with 1, 3, 2, 4, ... etc. Lets say you have a grounded wire at sw4. In this case, any switches to the left of sw4 in the series (i.e. 1, 3 and 2) will be ignored because the short to ground at sw4 will tie PR4 to ground. if the 2 pin was left then it would look like a strike because the ground is on the PR4 side of the series of switches and so it would look like a strike. On the other hand, if any of the pins represented by the switches to the right of sw4 (i.e. 5, 6, 10, 9, 8, 7) was left then the switch would break the short to ground at sw4 because the switch lies between the short and PR4. In this case, any one of those switches or any combination including at least one of those switches would look like a standing pins scenario.

    To test this theory:

    1) Disconnect the table harness plug with the machine at 0 waiting for first ball delivery.
    2) Test from K to chassis ground with an ohm meter. if you get 0 ohms then you have a short.
    3) Test from L to chassis ground with an ohm meter. If you get 0 ohms then you have a short.
    Make sure to test from both K and L to ground as testing only one may result in missing the short.

    If you find you have a short you can track it down as follows as outlined in the manual:
    1) Close or latch all respot cells
    2) Connect one meter lead to L and the other to the chassis ground.
    3) Release each cell one at a time in the order they appear in the string on the right side of figure 2 below (i.e. 1, 3, 2, 4, 5, 6, 10, 9, 8, 7) You have to use this order starting on the left at sw1 because if you release 7 first and the short was in 4 then 1, 3 and 2 being open would prevent the meter from seeing the short to ground. So if the short is at sw4 then you still wouldn't see it because sw1 would still be open and preventing the meter from seeing the short. In that case if you continued to close them from right to left then you would close 4, 2, and 3 without any indication the problem has been located. Finally if you close 1 last the problem will finally show up but you will think it's in sw1 because that's the one you closed when the problem appeared instead of sw4 where the problem really was.

    You should get infinite ohms (open circuit) until you close the cell with the short. The meter will then read 0 ohms and the short will be in the switch or it's connecting wires.

    Hope this helps. Let us know what you find.
    Attached Files

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    • #3
      Sorry, just realized they reversed the switch order in the left and right side of the same drawing. The order on the left side of the drawing has K to the left and L to the right with the numbers running from 7 to 1 starting on the left. On the right side of the drawing they have K on the right and L on the left with the numbers reversed. The only thing this changes is the explanation and so a short at sw4 would cause switches 1, 3 and 2 to indicate standing pins while the rest are ignored.

      Not sure why they flipped the lineup like that but the theory remains the same. Also the test procedure remains the same and release the cells in the same order listed above.

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      • #4
        wow...that's some serious knowledge on display...I think I get how the table wiring works, and this just reinforces my understanding...I really like the testing procedures...with that, I think I should be able to find the short to ground fairly easily...a broken wire just appears like a pin standing...a ground ends the circuit telling the machine its a strike...as long as its before the test location...thanks for the help...and enjoy as the sun starts coming out!

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        • #5
          Didn't you get those qubica strike cycle add-ons to bypass all the table wiring? It's early and the actual name is not coming to me right now lol

          Comment


          • #6
            That being said easiest way to test that is if the chassis doesn't have the L&K light lit up is start at 10 pin then 9 and so on until you find out where it respots the pins Normally, then you know what respot switchette is either broken or missing a wire.

            Remember the table wiring goes from the L to the terminal strip to 1, then back out to the strip then 3, 2, then strip to the 4,5,6 to strip then 10,9,8,7 to the strip all the way around the the K

            Comment


            • #7
              more good input...yeah...I was really hoping to do the camera mod to handle strike signals, but it appears to be over my head....this offseason, I hope to take another shot....going in this weekend to do the tests mentioned above....thanks again!

              Comment

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