Quick question. Got a firepower in which all displays are missing segment d, the bottom segment. It's an IC version, not discrete. I'm thinking it must be the BCD decoder, because if it were anything else, it would be only some displays missing the segment. So I guess question one is: Is there any way that IC4 could be involved, or is just likely to be one of the BCD decoders? And question two is: How to you tell which decoder it is? Are the ABCDs that come in on 4j6 just the names of what re more or less data lines? Why use the same four letters with two sub numbers?

So it's more likely to be a connector issue? It's got the problem across two mpu/driver boards, so it's not the boardset. I mean it could be both chips failing the same. It just seems unlikely.

Don't have the board here with me right this second. Your confirmation has made me feel much more confident in dealing with it, though, so I should be able to fix it this weekend. I'll let you know how it turns out.