I have a Bally Embryon and the displays have a ghosting effect where a digit in the display has a ghost one digit to the left of the digit being displayed. The game came with this problem. I narrowed down the problem to one of the display boards which, when disconnected, causes the problem to go away from all of the other displays. (Note, the problem display will ghost one segment to the right.) I've moved that display to different locations and regardless of where it is located, the ghosting returns when it is plugged in. All of the boards have upgraded resistors (done prior to me owning the game.) The only difference I can tell with the problem board is that the display looks to be replaced (it has commas where the other displays do not.) I've reflowed all the solder joints on the board and have replaced the 7-segment latch (CD4543 4543 IC CMOS BCD to 7-Segment Latch), and the problem has not gone away. I really don't know what I should be testing, so any help will be appreciated.

Ghosting effect. The left "0" is ghosting one segment to the left
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Problem display. Shows ghosting problem, except it ghosts one segment to the right. I move the problem display to the credit/ball slot.
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Problem display disconnected, ghosting effect is gone from the remaining displays
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Top of board of good display.
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Top of board of problem display. Note that the header has been replaced.
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Front of problem display. Note that the display has commas.
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Front of a good display. Note that the display does not have commas.
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Good display not showing ghosting when problem display is disconnected
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Thanks for the tips. Sorry if I wan't clear, but the ghosting is affecting all digits. R5 and the other resistors are in spec. I'll also order some transistors.

I don't think my problem is the wiring harness as the problems come from one board. But let me know if there is something that I am missing.

Good idea, but I am one without a scope. I'll see if I can get a friend to help out.

There are some pretty ugly solder joints going to the display. I did give them a reflow with an iron, but didn't remove and redo (which I can do). Unfortunately, there does look to be some bad damage in places.

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I was wondering if the problem was in the display or in the board, so I desoldered the display and plugged in the board. The ghosting still persists when the board is plugged in, so I think the problem is somewhere on the board. Attached is a photo of the board highlighting the holes where the display would be connected and the topside of the board.

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Absolutely. I was being lazy. Now I am man on a mission, armed with a desoldering gun.

Success! Thanks PinballManiac, you put a fire under me to clean up those solder joints put down by someone else. I removed the solder from the header, resoldered cleanly (thanks in no small part to TerryB's soldering guide), and reinstalled the board without the display. No ghosting. Soldered back in the display and everything works like a champ. Also, thanks barakandl and ralph for the helpful suggestions, too.

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My problem was at the header, not the display. In a previous post, I took of the display and the problem persisted (ghosting on the other displays). Once I removed the solder and resoldered the header, the problem went away with the display STILL removed from the board (no ghosting on the other displays). Then I reattached the display and the problem was still fixed (no ghosting on the other displays.)

However, the solder joints for the display were not in good shape and I am glad I redid them, too.

They definitely looked pretty bad.

That would have been a good idea. I'll do it the next time I open the backbox.