TECH: BK / System 7 P1 & P2 display anomaly...

Archived from groups: rec.games.pinball (More info?)

Intermittantly, my player 1 and player 2 displays (ONLY these two
displays) start flickering and acting odd. P1 flickers with different,
dimmer digits showing in a couple of places... P2 starts to show all
dim 7's. The P2 7's pulse and flash with the P1 display like it's
somehow getting some of the same information.

The other odd thing noticed is that in attract mode, the flickering and
dim 7's ONLY show up when displaying the score of the last game played,
not the high score to date. The high score to date displays fine.
This seems important, but I'm not sure why it would be happening.

Any input would be helpful.

Thanks, as always, in advance.
5 answers Last reply
More about tech system display anomaly
  1. Archived from groups: rec.games.pinball (More info?)

    First thing to try is re-seat the edge connectors to display 1 and 2 at
    least 7 times. If this doesn't work, swap your player 3 and 4 displays
    to see if the same thing is happening. If so, you've narrowed it down
    to a display driver board problem. Then if it still occurs, remove the
    display driver board and check for cold solder or open solder joints at
    the header pins. Inspect the entire board for any open or cold solder
    joints. That should do it.

    John
  2. Archived from groups: rec.games.pinball (More info?)

    I have seen problems like this occur when CPU and/or driver board
    chips sockets are bad. For example, any SCANBE sockets? Something
    to try, if the PIAs are socketed, is to switch them around. There
    are 3 on the driver board and one on the CPU. Don't go nuts but
    they are all 6821 PIAs and just start by swapping 2 of them (if
    possible start with the CPU PIA), and see if anything changes.

    multieng@netzero.net wrote:
    > Intermittantly, my player 1 and player 2 displays (ONLY these two
    > displays) start flickering and acting odd. P1 flickers with different,
    > dimmer digits showing in a couple of places... P2 starts to show all
    > dim 7's. The P2 7's pulse and flash with the P1 display like it's
    > somehow getting some of the same information.
    >
    > The other odd thing noticed is that in attract mode, the flickering and
    > dim 7's ONLY show up when displaying the score of the last game played,
    > not the high score to date. The high score to date displays fine.
    > This seems important, but I'm not sure why it would be happening.
    >
    > Any input would be helpful.
    >
    > Thanks, as always, in advance.
  3. Archived from groups: rec.games.pinball (More info?)

    this is excellent advice too. because all all the score
    displays light, it puts stress on the regulated 100 volt
    power section. as the displays light see if the voltage
    stay steady at +100/-100. now there could be a 90 volt
    zener diode installed too, so it could be +90/-90, but
    most people don't do that (some do to increase display
    life).

    Fred Kemper wrote:
    > Start by checking your high voltage section
    > of the power supply. (The +100vdc and -100vdc).
    >
    > If okay, proceed.
    >
    > Try swapping, (with the power off!), players 1&2
    > with players 2&3. See if problem moves with the
    > display(s). If so, you probably have a faulty display
    > tube. Swap between known "good" display and
    > bad one(s) to isolate problem.
    >
    > --
    > Fred
    > TX
    > CARGPB#8
    > ******************
    >
    > <multieng@netzero.net> wrote in message news:1121376879.537662.283400@g47g2000cwa.googlegroups.com...
    > > Intermittantly, my player 1 and player 2 displays (ONLY these two
    > > displays) start flickering and acting odd. P1 flickers with different,
    > > dimmer digits showing in a couple of places... P2 starts to show all
    > > dim 7's. The P2 7's pulse and flash with the P1 display like it's
    > > somehow getting some of the same information.
    > >
    > > The other odd thing noticed is that in attract mode, the flickering and
    > > dim 7's ONLY show up when displaying the score of the last game played,
    > > not the high score to date. The high score to date displays fine.
    > > This seems important, but I'm not sure why it would be happening.
    > >
    > > Any input would be helpful.
    > >
    > > Thanks, as always, in advance.
    > >
  4. Archived from groups: rec.games.pinball (More info?)

    Start by checking your high voltage section
    of the power supply. (The +100vdc and -100vdc).

    If okay, proceed.

    Try swapping, (with the power off!), players 1&2
    with players 2&3. See if problem moves with the
    display(s). If so, you probably have a faulty display
    tube. Swap between known "good" display and
    bad one(s) to isolate problem.

    --
    Fred
    TX
    CARGPB#8
    ******************

    <multieng@netzero.net> wrote in message news:1121376879.537662.283400@g47g2000cwa.googlegroups.com...
    > Intermittantly, my player 1 and player 2 displays (ONLY these two
    > displays) start flickering and acting odd. P1 flickers with different,
    > dimmer digits showing in a couple of places... P2 starts to show all
    > dim 7's. The P2 7's pulse and flash with the P1 display like it's
    > somehow getting some of the same information.
    >
    > The other odd thing noticed is that in attract mode, the flickering and
    > dim 7's ONLY show up when displaying the score of the last game played,
    > not the high score to date. The high score to date displays fine.
    > This seems important, but I'm not sure why it would be happening.
    >
    > Any input would be helpful.
    >
    > Thanks, as always, in advance.
    >
  5. Archived from groups: rec.games.pinball (More info?)

    grus_jc@yahoo.com wrote:
    : First thing to try is re-seat the edge connectors to display 1 and 2 at
    : least 7 times. If this doesn't work, swap your player 3 and 4 displays
    : to see if the same thing is happening. If so, you've narrowed it down
    : to a display driver board problem. Then if it still occurs, remove the
    : display driver board and check for cold solder or open solder joints at
    : the header pins. Inspect the entire board for any open or cold solder
    : joints. That should do it.

    Highly doubtful it's the connectors.

    Most likely, it's one of the BCD -> 7 segment decoders going.

    --
    Mark Spaeth mspaeth@mtl.mit.edu
    50 Vassar St., #38.265 mspaeth@mit.edu
    Cambridge, MA 02139
    (617) 452-2354 http://rgvac.978.org/~mspaeth
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