Hi, I picked up an empty 4x8 Q-bus chassis at VCF-East this year. It's labelled "USDC CSS-823 Processor System" on the outside. It's not a DEC backplane, but the chassis is light aluminum, smaller and in some ways nicer than my pile of BA23s. It includes a switching power supply, LTC and q-bus termination, and I confirmed it's wired for Q22. I was hoping to transplant an 11/83 into it, since it will fit more comfortably in my work area. It has lit DCON/RUN/LTC/HALT buttons on the front pane. The etching on the backplane says something like "MDB Systems, Inc. East Orange, CA 92665"
Unfortunately, I discovered slots are all wired Q22/Q22, no top ABCD (Q22/CD) PMI slots like a BA23. So, not good for an 11/83 CPU wired for PMI on slots C-D. So, I was hoping I could get my KDJ11-B (quad-wide 11/73) running in it. Upon power up or reset I get "Testing in progress. Please wait" on the serial console, and the LEDs get stuck on test 56. CTRL-C doesn't do anything yet, and my only options seem to be to hit reset, or if I hit the run/stop toggle, I can reset to the ODT prompt. This is with either just the KDJ11-B in the top slot, or with the addition of a suitably configured MSV11-QA in the next slot. If I turn off the LTC on the front panel, I get the expected Error 61 M8190 clock error, PC and register values, and options to re-run once or loop on test, so I know the LTC is working. I confirmed the KDJ11-B works fine in a BA23, getting past test 56. I also tried an 11/53 CPU here in the ABAB backplane and that gets past the self tests into dialog mode, but I really would like to get the KDJ11-B working in this chassis. I do see that a couple traces to the KDJ11-B C-D slots besides the Grant Continuity connections. I assume since the KDJ11-B has those Grant Continuity connections on slots C-D, it can run in a qbus/qbus Q22/Q22 quad Q-bus slot. I noticed the FP "RUN" lamp never comes on (and is not burned out), but maybe that's normal -- monitoring something on the bus that doesn't happen during power on self test. Does anyone here have suggestions about next steps in diagnosing this? https://archive.org/stream/bitsavers_decpdp1111aintNov86_5833755/EK-1184A-MG-001_1184maint_Nov86_djvu.txt ----------------------------------------------------------------------------- 4.10.18 Exit Standalone Mode (Test 56) In the 22-bit mode, the exit standalone mode is checked by using the guaranteed timeout address of 17 760 000 to verify that the timeout logic works without hanging up the CPU. ----------------------------------------------------------------------------- -- Mark G. Thomas (m...@misty.com), KC3DRE
