TECH: Williams Sys 11B Display Test

[Guest]

Archived from groups: rec.games.pinball (More info?)

I just replaced the 7-digit alphanumeric display in PLRY1 position on the
Williams Space Mission pin.
When I run the DISPLAY TEST, the upper half (period) of the last comma to
the right always remains lit.
It never goes out under any test or circumstance. Since I acquired this pin
with the upper two displays broken, I am not sure if this behavior is
normal. The bottom displays which are just numeric do not do this. Can
someone check theirs for me and let me know? All the other segments run 100%
under the test.
Thanks!

 

[Guest]

Archived from groups: rec.games.pinball (More info?)

here's what I would go through:

1) solder shorts
2) broken traces (especially at the annular ring)
3) UDN chips on the display driver board
4) PIC on the CPU board
5) Cold solder joints on ribbon cable connectors (and glass itself)

-Gregg B.