X's & O's
Bally, 1983Hi!
This morning my pinball surprise me a bit.
The player#1's display looks like, try to tells me something in klingon language... 
Not all the time, sometimes works ok, but mostly like this. I check its connector, but nothing happens... The other 4 display are working perfectly. Any idea? Thanks!
If its flickering from good to bad my guess would be a connector or cracked solder joint.
What pin is this?
Hm, interesting.
Both of the solderings looks good,as You can see it in the picture. The pins,and the display's too...
But, it was very dirty, this was the only part of my pinball, what isn't cleaned, touched. Now I clean them well, and than start the macnihe. Looks good, I play a few, and suddenly start to does again... I move the connectors, the wires, but nothing happens. Then I realise, one bulb is not working on my playfield, bonus board. I move the board's connector, and then, all error was fixed. Both the bulb, and the display. Then I play 20minutes, and everything working perfectly.
Can be a connection between the two errors, or that was just random? Before this, I realised, if one connector on my backbox lamp board was not installed properly, few laps not working, and the drop targets aren't work... But than, I think, it's just a random problem... Can this be?
Did you look at the solder joints under magnification? If not you may not be able to see the very small fractures in a cold solder joint. Nearly all of these displays from this era suffer from this, so as a rule I suck all of the old solder off and then resolder the connector pins to eliminate that as an issue before doing any other diagnostic work.
Do the numbers on the display change or are the segments that are lit always the same?
Quoted from Craigmack:Did you look at the solder joints under magnification? If not you may not be able to see the very small fractures in a cold solder joint. Nearly all of these displays from this era suffer from this, so as a rule I suck all of the old solder off and then resolder the connector pins to eliminate that as an issue before doing any other diagnostic work.
Do the numbers on the display change or are the segments that are lit always the same?
Yes, Yes with these displays always reflow the solder first. Always. Your eyes are not good enough to see the cracks that could be causing this. Even if it dosent look like the problem it must me done. If not, no matter how much diagnosising you do the good chance you have bad solder joints still lingers. Besides, if there not cracked now by the time your done diagnosising you display problem they likely will be. You will be glad in the future you did.
Hm, when it does this (in the last two hours oly 2mins),then flashing,dimming.
As i remember,always different segments. But if I move it,nothing happens... The pins,or the display solderig needs to reflow,what do you think?
I try to make a video from it...
You may want to test the legs of the CPU chips that drive those displays (because of segment loss not whole display loss) but, I agree with Blackbeard, your problems seem very hit and miss which leads me to believe it could be a loose ground pin connection (because of the flickering and dimming of displays), or worn out pins period.
have you removed the display and swapped it with another?
this should let you know if it's a board/display issue, or a connector issue...
Quoted from Craigmack:Did you look at the solder joints under magnification? If not you may not be able to see the very small fractures in a cold solder joint. Nearly all of these displays from this era suffer from this, so as a rule I suck all of the old solder off and then resolder the connector pins to eliminate that as an issue before doing any other diagnostic work.
Do the numbers on the display change or are the segments that are lit always the same?
Dumb question, you redo every single connection on the board?
Not to be off topic, but did you guys ever get your order from Mad amusement yet? Most are saying reflow solder so do that first then if it persists then ask another question, one at a time as to not overwhelm yourself or confuse us.
Quoted from FatsoPilot:Craigmack said:Did you look at the solder joints under magnification? If not you may not be able to see the very small fractures in a cold solder joint. Nearly all of these displays from this era suffer from this, so as a rule I suck all of the old solder off and then resolder the connector pins to eliminate that as an issue before doing any other diagnostic work.Do the numbers on the display change or are the segments that are lit always the same?Dumb question, you redo every single connection on the board?
Which board? Sometimes playes one's, next time player 4's doing it...
And sometimes working great. Must be a contact problem,but where?
I don't know much about Bally's, most that I have had were Gottliebs. However, I do think it is a connection problem. Reseat ALL the connectors that run from your MPU board to the displays and from the MPU to your driver boards. Hell probably wouldn't be a bad idea to just reseat all your connectors and look at them for corrosion etc. while you do it.
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Maglód
Bossier City, LA