Background - I have a PDP 11/40 that came to me with a CPU backplane and a general purpose 4 slot peripheral backplane. The CPU backplane came to me connected to the 4 slot via a std 11/40 M981. In the 4-slot I have I have a working 64K solid-state RAM card, M7856 serial card, M9312 bootstrap/console card, and an RL02 drive controller. I can access RAM from the console, run the console program (monitor program) off the M9312 through the serial card. I can't boot yet off the RL02 and I am thinking this is due to a termination issue, not sure yet. I decided I need more backplane to go any farther.
So I decided to insert two 32K core memory backplanes in between the original two backplanes that came with the system. My plan is to replace the solid-state RAM card with core, and this will free up a slot on the 4-slot backplane for a terminator. Am I correct in my logic? I have connected the "new" backplanes using M920's. Imagine the original system with a core backplane wedged in the middle. Power seems fine, DC LO AC LO fine. Right now there is nothing in the core backplanes, First I want to verify that I have them arrayed correctly and that I can still communicate with the (now) 4th backplane in the back. I can run "chase the lights" from the console but the serial card seems to have stopped working. It appears that the console program is being loaded and runs from the M9312 but nothing is appearing on the terminal. I cannot send an "A" to the terminal, the most basic test I can think of. Could be the the M7856 card decided to die on me just now, or something else is wrong. Does anyone have a PDP 11 /05/10/35/40 and have experimented about what you can and can't do with backplanes? I know that there are a lot of variables here, so I'd like to start with the basics Basic Question #1 Do I need grant cards in *every* empty slot of the core backplane, including the end slots with the M920's? Basic Question #2 Can you only use the core backplanes for core memory (assume yes), or are they capable of holding other types of cards temporarily? (yes/no/maybe) I am researching the system config on my own, but I thought if anyone had any advice I'd love to hear it, make troubleshooting a little easier. I have read up on the subject: http://retrocmp.com/how-tos/setup-a-pdp-11-unibus-backplane https://trmm.net/PDP-11 I see this is not a simple little thing. Working to find more GC cards now. Thanks b -- @ BillDeg: Web: vintagecomputer.net Twitter: @billdeg <https://twitter.com/billdeg> Youtube: @billdeg <https://www.youtube.com/user/billdeg> Unauthorized Bio <http://www.vintagecomputer.net/readme.cfm>
