(Topic ID: 278803)

Gottlieb system 80 display problem

By Haymaker

1 year ago



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  • 9 posts
  • 4 Pinsiders participating
  • Latest reply 1 year ago by Haymaker
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#1 1 year ago

I'm trying to sell my haunted house and I'm going through it just trying to take care of some minor issues. Right now, the one I'm having trouble with is 2 of the displays have segments locked on. They will always show a 1 regardless of what number should be displayed. It's only on the credit/match display and the basement display so i can't even switch them around. My first assumption was just that the card edge contacts were dirty, but after cleaning and even retinning the problem remained.

Next step I'm wondering if i need to repin the connector or what I'm leaning more toward is a bad chip somewhere (7404? 7432?)

Any help to point me in the right direction? In the pics you can see credits should read 0, and the lower display should be all 0's not 0's with lines through them
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#2 1 year ago

This problem is usually due to slight corrosion on the connectors.
Try removing then re-installing all display connectors and see if it
changes.
Steve

#3 1 year ago
Quoted from zarco:

This problem is usually due to slight corrosion on the connectors.
Try removing then re-installing all display connectors and see if it
changes.
Steve

Thanks for the info, but I not only tried that, but I also tried cleaning them with a fiberglass brush as well as re-tinning them, all 3 things and no luck

#4 1 year ago

For testing you can swap the basement display with one of the player displays.
Are the displays 'stuck' or do they just showing an additional 'I'?

#5 1 year ago
Quoted from bontango:

For testing you can swap the basement display with one of the player displays.
Are the displays 'stuck' or do they just showing an additional 'I'?

The displays work fine other than the segments in my pictures always being on. You can decode the scores and credits fairly easily and its never really bothered me that much, but I figure if I'm going to find a new owner, I should probably take care of that issue. Good tip on swapping the basement display, I couldn't remember if it matched the normal displays or not.

#6 1 year ago

I've seen this happen before on a black hole and eventually traced the source of the problem to an issue with the lower playfield display. Disconnecting it prevented the problem from appearing, other screens worked fine. It was frustrating to troubleshoot since it would only appear after being on for a while.

I originally thought it was related to the OR gate on the ball/credit board (which is used to share that segment since the ball/credit board does not have the extra "1" segment) - I can at least say that replacing this chip did not help.

#7 1 year ago
Quoted from Haymaker:

The displays work fine other than the segments in my pictures always being on.

The basement display and the credit display do share the same segment driver. The segment for the "|" is the "h" segment.
Looks like you have either a contact problem with pin24 of J2 on the MPU board or the driver for the "h" segment is faulty.
For this "h" segment the driver is a part of Z17 on the MPU board (the other parts of that IC do drive display digits 1..5).
Gottlieb did use a 7404, acceptable subs are 74LS04 and 74HCT04.

#8 1 year ago
Quoted from bontango:

The basement display and the credit display do share the same segment driver. The segment for the "|" is the "h" segment.
Looks like you have either a contact problem with pin24 of J2 on the MPU board or the driver for the "h" segment is faulty.
For this "h" segment the driver is a part of Z17 on the MPU board (the other parts of that IC do drive display digits 1..5).
Gottlieb did use a 7404, acceptable subs are 74LS04 and 74HCT04.

Excellent info! This should help me get on the right track. Thank you!! I will update if I get things figured out

#9 1 year ago

lol I feel so dumb, I just reseated the connector and it's working perfectly now. Still I'm glad i learned a little more about the operation of the system 80

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