TECH: Bally -17 ERA Player 3 Display showing Credit/Ball in Play Data

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Hey all,

Taking a quick break from the cocaine and weed posts for some actual pinball discussion! ;)

Just resurrected a -17 MPU and have one last problem to track down.

Everything is working fine, but player 3 display is displaying the data identical to credit display. Somewhere the data lines are crossed, no obvious shorts on the board and the games main board does not exhibit this behavior.

I checked U20 for a short between pins 2 & 11 and no issues there. I can't read what type of chip this is, but the fact that it's socketed makes a swap an easy check. Also looks like the pad at pin 2 is gone, however continuity checks from the chip itself buzz out as good.

Any ideas on what to check next or what kind of chip that is?

Thanks all -

Pete

[John Robertson]

Post by ***@gmail.com
Hey all,
Taking a quick break from the cocaine and weed posts for some actual pinball discussion! ;)
Just resurrected a -17 MPU and have one last problem to track down.
Everything is working fine, but player 3 display is displaying the data identical to credit display. Somewhere the data lines are crossed, no obvious shorts on the board and the games main board does not exhibit this behavior.
I checked U20 for a short between pins 2 & 11 and no issues there. I can't read what type of chip this is, but the fact that it's socketed makes a swap an easy check. Also looks like the pad at pin 2 is gone, however continuity checks from the chip itself buzz out as good.
Any ideas on what to check next or what kind of chip that is?
Thanks all -
Pete

14502B or 4502B Hex buffer.

Download the schematics from IPDB.org

John :-#)#

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Thanks John!

[Grojohn]

Post by ***@gmail.com
Hey all,
Taking a quick break from the cocaine and weed posts for some actual pinball discussion! ;)
Just resurrected a -17 MPU and have one last problem to track down.
Everything is working fine, but player 3 display is displaying the data identical to credit display. Somewhere the data lines are crossed, no obvious shorts on the board and the games main board does not exhibit this behavior.
I checked U20 for a short between pins 2 & 11 and no issues there. I can't read what type of chip this is, but the fact that it's socketed makes a swap an easy check. Also looks like the pad at pin 2 is gone, however continuity checks from the chip itself buzz out as good.
Any ideas on what to check next or what kind of chip that is?
Thanks all -
Pete

Hello,

I would unplug the coin door, then power on. If problem goes away you have a short somewhere on coin door.

John