Revere, MA
The player 3 display on my Gorgar flickers in the left three digits whenever the leftmost digit is a 1 or 7. I'm sure there's minor traces with other digits, but it's most noticeable with a 1 or 7. I've swapped the Player 3 and Player 1 displays, and the problem doesn't follow, so I suspect the problem is with the current being applied.
The manual says that the Player 3 100,000, 10,000 and 1,000 digits come out of 4J3-5, 6, and 3, respectively. The problem most noticably manifests when segments B and C are the main digits being displayed, but it also occurs when just segment A is added to the mix. These segments come out of 4J3-10, 13 and 9, respecitvely.
4J3-5, 6 and 3 come out of pins 17, 18 and 16 on IC12, respectively. Segments B, C and A are a bit harder to follow. It looks like they're part of a parallel circuit that comes out come out of pins 13, 16 and 17 on IC10, with each of them going through one of the resistors in R8-R14.
Can anyone point me to a breakdown of how these displays actually work? I'm not sure what the 10's, 100's, 1000's and other connections do as opposed to the segment connections. Are the boards driven by some kind of signal that tells them to light up or blank out certain segments on a certain digit? For instance, If I go from 1000 to 2500 points, does the master board tell the slave board to:
1) Light segments A, B, E, D and G on the 10,000s digit
2) Blank out segments F and C on the 10,000's digit
3) Light segments A, C, D, F and G on the 1,000's digit
4) Black out segments B and E on the 1,000's digit
... and so on at such a speed as to make it all seem near-instantaneous? Or does it work some other way?
Thanks!
