On Fri, Jan 1, 2021 at 10:06 PM Eric Smith <space...@gmail.com> wrote:
> On Fri, Jan 1, 2021 at 10:04 PM Josh Dersch via cctalk < > cctalk@classiccmp.org> wrote: > >> Discovered a broken wirewrap wire on the 11/70 I'm slowly working on, it's >> on the last slot (44), and runs from BD2 to ??. White wire, part of a >> white/black twisted pair. I've been looking but haven't found a wire list >> for the backplane >> > > There would be two different 11/70 backplane wirelists, depending on > whether your CPU is a KB11-B or a KB11-C. Unfortunately I don't have either > wirelist. > > If your 11/70 has an M8133 and an M8138, it's a KB11-B. > If it has an MB8123 and MB8138-YA, it's a KB11-C. > I have a KB11-C here. > You're undoubtedly aware that the A/B section of slot 44 is for the Unibus > cable or terminator, so BD2 is signal BR4 L. It should probably go to the > BR4 L pin of the slot 44 SPC, which would be pin DH2, which would be bussed > through DH2 of the other SPC slots (40-43). > You know, that really should have occurred to me. Convenient that the break happened on such a convenient pin! Thanks for the tip, I'll double-check everything tomorrow and see if I can find my wire-wrap tool... - Josh > > RH70 Massbus controllers normally use BR5 L, but I suspect that the BR4 L > line would be wired to their slots as well. I don't have an RH70 print set, > so I don't know the details. From the RH70s (or slot 40, if BR4 L doesn't > go to the RH70s), I would expect it to go to the Trap & Msc Control board > (TMCB) in slot 11, pin FP1. > > Best regards, > Eric > >
