Can't figure out display issue...

vipe155

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I have an annoying missing B segment on the Right Display of a Sys. 11 game. It's a Bally, and uses two 16 character displays, Left and Right. Since I bought it, the segment has been missing. All the other issues are out of the way on the game, except for this.

I tracked through the schematic, and the B segment goes through a 10k resistor, 4049 chip, 7018 chip, and an 18k resistor. All of these checked out, but just to be sure I replaced the cheap resistors and put a new 4049 chip in just in case. 7018s are harder to find and more expensive, but it checks out anyway according to my multimeter.

Pinrepair lists a capacitor/resistor network on the main board as a possible culprit, but this doesn't seem to be that kind of issue either. So, what else could it be? Could the glass be shorted?

IMG_1055.jpg
 
are you getting the proper voltage to the display? are the pins on the connector good, clean, and no cold solder joints?
 
A Bally system 11 ?????

Stop knitpicking already :p
Probably said Bally because it's called "The Bally Game Show"

@OP - I would start with the easy stuff - wiggle cable adding pressure on both ends looking for change. Reflow the appropriate headers.
 
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No, I didn't mean a "Bally" System 11, but it uses Williams System 11 boards. I don't really get why Midway just didn't consolidate the two into one company since both did the same thing and used basically the same technology.

I did mention it's a Bally because I don't know if any Williams machines used this exact type of display board. A lot of the Williams Sys. 11 games I've seen seem to use 4 display boards.
 
Can you switch the displays to determine if it is the display or the electronics driving each 16 digit display?
 
Can you switch the displays to determine if it is the display or the electronics driving each 16 digit display?

I wish, but the left and right displays have different connections. Switching them just displays garbled text. But, I did do that just to see if the right display switched (to the other side) shows anything in the B segment, and it doesn't.
 
Did you try reversing the cable ,both ends (red band NOT on pin #1) and see if the problem moves with the cable? If so its the cable.
 
Well, I think I screwed something up. I tried switching the ribbon cable around, but I believe I may have switched the red band on the cable around (on accident:(). It sounded like a fuse popped, and I took out the +100/-100 fuses and tested them out. One of them has no resistance, so I guess it blew.

Problem is, when I replaced the fuses, I still get no display at all. So, have I wrecked something in the high voltage section?
 
Measure the + & - 100v what are they?

I can try measuring them, but I just got everything put back together, put in two new -100 and +100 volt fuses and the -100 immediately blew. If the HV needs to be rebuilt, it won't be a big deal. I was going to order some stuff in the next week anyway, and I was thinking about reducing the voltage to 91V before this happened.
 
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