UNIBUS configuration
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by Bill Degnan - 08/31/2015 10:59 |
 UNIBUS card positioning. Click for larger image.
Dave M stopped by and made adjustments to the UNIBUS Non Processor Grant (NPG) lines on the UNIBUS. I had been asking around how exactly to make sure the NPG was happening when it needed to happen and disconnected when it should be missing. We did the following, for space reasons. 1) Removed NPG from wirewrap of last 5-slot backplane row per requirements for installation of M7762 RL11. I understand now better how the NPG works. 2) found pin on backplane that already did have this jumper removed and put a NPG card in this slot (3-4). This is a requirement for proper operation of the UNIBUS. This is the slot also used by the 9312 (1-2). Card placement Front Card placement Corner. Note, you can't see all of the way to the corner in this photo. If you could see where the M7762 connects to the backplane you'd see I've run out of slots. The "expansion" has no terminator a the end. Does not seem to be a problem, but not 100% sure. It is a 5-slot backplane. 3) Ran bootstrap. Now, Some code is written into the 000 000 page from the disk, but RL11 fails to boot. NEXT: - Check drive cable - measure voltage across a M7762 cap while simultaneously boosting voltage at the h744 regulator level. -->5.1v - I have two or three h744's on this system so I have to id which one is driving - step through bootstrap, compare with what I had before, there is a diag address I can check too - Verify all drive, pack, and cable combinations return the same result. - Is the lack of a terminator preventing bootstrap (unlikely?) - Could it be that there is a conflict between the M9312 and the drive controler ROMs? Try booting without the CONSOLE ROM in place. Reply |
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