Bally Display Ghosting

dieseldogpi

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I looked through the pin-wiki and cannot figure out why I am getting ghosting on my displays. It is a Mr and Mrs Pacman Pin. 5 Displays on the bacbox, one on the playfield. The 5 on the back box have the ghosting issue. I have swapped the displays, still an issue, changed the IC on the board for the displays, changed the resistors, still ghosting. I also had the game running with the original board and a brand new Alltek Ultimate MPU and still the issue. HELP! Thanks guys.
 
What exactly do you mean by ghosting? Did you rebuild your display connector that goes to the MPU? Sounds like a wiring issue or one display in particular effecting all of the others. Only hook up one and see if you have the issue. If you don't then start connecting displays one at a time until you find the one that causes the problem.
 
By ghosting I mean if there is a 5 in the third digit (from the right) a faint 5 is visible in digit 4. This makes it next to impossible to read. I should have posted a pic, i will later. I will try the one at a time thing, I have not tried that yet.
 
Yeah it is usually one display that causes wacky things to happen in all of them. It sounds like one of them has a bad digit decoder.
 
Yeah it is usually one display that causes wacky things to happen in all of them. It sounds like one of them has a bad digit decoder.

Agreed. I would start by trying the displays one at a time. Remember that most of the signals going to the displays are connected to all of them in parallel so one bad display can do funky things.
 
OK, so taking your advice, I plugged in all of the displays individually and they all worked perfectly. Then I plugged in 3 at a time and noticed one worked perfectly and the other two had the issue. So when I unplugged that one display that works, all the others worked perfectly. So what does this mean. This one display works, but causes the other ones to have this ghosting issue. I had already replaced the IC and fixed any cracked header pins. ideas? Thanks guys.
 
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