Quoted from bayoubilly70:Bally 6-digit displays... I'm working on Star Trek. I have one display with the same segment out across it. I replaced the appropriate MPS-A42 transistor (Q18), and also the decoder chip. The segment "f":
http://web.archive.org/web/20071019004706/www.pinrepair.com/bally/index3.htm#display
is still out.
The problem follows the display if I change it in another location, so its not the inputs. Its the display board.
One could argue that I replaced the bad transistor and decoder chip with defective parts, but not likely.
Any ideas?
1) does the BCD ic chip work in test... scope/logic probe...
2) if so does the transistor circuitry that drives the "F" segment work?...
3) if so then most likely the gas discharge display is bad...
4) it has happened to me...
5) best to get displays with missing digit position rather than segments.
New Brighton, PA
