Stuck bits on 11/73 Clearpoint 4MB memory - how to repair?

Jacob Ritorto jacob.ritorto at gmail.com
Fri Feb 12 17:32:29 CST 2016


Hi,
    Seems I have bits 4 and 3 sticking on my Clearpoint QRAM-2-SAB-1 88b
4MB memory in my pdp11/73.

    Can anyone offer hints as to how to identify which component is broken
and how to go about repairing this?

    It's the only memory board in this machine, so I guess the problem
might actually be a bus or processor board, right?  I have no other q-bus
memory to test with, so can't do swapping / process of elimination to be
sure.

    Here's the manual:
http://www.arclightindustries.com/docs/Clearpoint-88B.pdf (which I probably
should add to manx or archive.org or something).

    Here's a snippet of the VMJA diags run illustrating bits 4 and 3
sticking.  During the next VMJA run, all addresses were showing up as
errored instead of just the ones ending in xxx000xx, so I guess it's
getting worse!

@173000g

                              Starting system
BOOTING UP XXDP-XM EXTENDED MONITOR

XXDP-XM EXTENDED MONITOR - XXDP V2.5
REVISION: F0
BOOTED FROM DL0
124KW OF MEMORY
NON-UNIBUS SYSTEM

RESTART ADDRESS: 152000
TYPE "H" FOR HELP !

.R VMJA??
VMJAB0.BIC

 CVMJAB0  ECC/PARITY MEMORY DIAGNOSTIC
   11/83 CACHE AVAILABLE
SWR = 000000  NEW = 000040


               CSR MAP

CSR     0 1 2 3 4 5 6 7 8 9 A B C D E F
MEMTYPE P


CSR NUMBER 0 CONTROLS TOO MANY BANKS
  2044K OF Q-BUS PARITY MEMORY
  2044K WORDS OF MEMORY TOTAL

                        MEMORY CONFIGURATION MAP
                             16K WORD BANKS
                1       2       3       4       5       6       7
        012345670123456701234567012345670123456701234567012345670123
ERRORS
MEMTYPE PPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPP
CSR     000000000000000000000000000000000000000000000000000000000000
PROTECT PP
            1       1       1       1       1       1       1
            0       1       2       3       4       5       6
        456701234567012345670123456701234567012345670123456701234567
ERRORS
MEMTYPE PPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPP
CSR     000000000000000000000000000000000000000000000000000000000000
PROTECT
        1
        7
        01234567
ERRORS
MEMTYPE PPPPPPPP
CSR     00000000
PROTECT
MEMORY DATA ERROR
  PC    BANK  VADD     PADD     GOOD     BAD     XOR  CSR  MTYP INT PAT

027606   10  060000  01000000  000010  000030  000020  0     P       27
027606   10  060002  01000002  000010  000030  000020  0     P       27
027606   10  060004  01000004  000010  000030  000020  0     P       27
027606   10  060006  01000006  000010  000030  000020  0     P       27
027606   10  060010  01000010  000010  000030  000020  0     P       27
027606   11  060000  01100000  000011  000031  000020  0     P       27
027606   11  060002  01100002  000011  000031  000020  0     P       27
027606   11  060004  01100004  000011  000031  000020  0     P       27
027606   11  060006  01100006  000011  000031  000020  0     P       27
027606   11  060010  01100010  000011  000031  000020  0     P       27
027606   12  060000  01200000  000012  000032  000020  0     P       27
027606   12  060002  01200002  000012  000032  000020  0     P       27
027606   12  060004  01200004  000012  000032  000020  0     P       27
027606   12  060006  01200006  000012  000032  000020  0     P       27
027606   12  060010  01200010  000012  000032  000020  0     P       27
027606   13  060000  01300000  000013  000033  000020  0     P       27
027606   13  060002  01300002  000013  000033  000020  0     P       27
027606   13  060004  01300004  000013  000033  000020  0     P       27
027606   13  060006  01300006  000013  000033  000020  0     P       27
027606   13  060010  01300010  000013  000033  000020  0     P       27
027606   14  060000  01400000  000014  000034  000020  0     P       27
027606   14  060002  01400002  000014  000034  000020  0     P       27
027606   14  060004  01400004  000014  000034  000020  0     P       27
027606   14  060006  01400006  000014  000034  000020  0     P       27
027606   14  060010  01400010  000014  000034  000020  0     P       27
027606   15  060000  01500000  000015  000035  000020  0     P       27
027606   15  060002  01500002  000015  000035  000020  0     P       27
027606   15  060004  01500004  000015  000035  000020  0     P       27
027606   15  060006  01500006  000015  000035  000020  0     P       27
027606   15  060010  01500010  000015  000035  000020  0     P       27
027606   16  060000  01600000  000016  000036  000020  0     P       27
027606   16  060002  01600002  000016  000036  000020  0     P       27
027606   16  060004  01600004  000016  000036  000020  0     P       27
027606   16  060006  01600006  000016  000036  000020  0     P       27
027606   16  060010  01600010  000016  000036  000020  0     P       27
027606   17  060000  01700000  000017  000037  000020  0     P       27
027606   17  060002  01700002  000017  000037  000020  0     P       27
027606   17  060004  01700004  000017  000037  000020  0     P       27
027606   17  060006  01700006  000017  000037  000020  0     P       27
027606   17  060010  01700010  000017  000037  000020  0     P       27
027606   20  060000  02000000  000020  000030  000010  0     P       27
027606   20  060002  02000002  000020  000030  000010  0     P       27
027606   20  060004  02000004  000020  000030  000010  0     P       27
027606   20  060006  02000006  000020  000030  000010  0     P       27
027606   20  060010  02000010  000020  000030  000010  0     P       27
027606   21  060000  02100000  000021  000031  000010  0     P       27
027606   21  060002  02100002  000021  000031  000010  0     P       27
027606   21  060004  02100004  000021  000031  000010  0     P       27
027606   21  060006  02100006  000021  000031  000010  0     P       27
027606   21  060010  02100010  000021  000031  000010  0     P       27
027606   22  060000  02200000  000022  000032  000010  0     P       27
027606   22  060002  02200002  000022  000032  000010  0     P       27
027606   22  060004  02200004  000022  000032  000010  0     P       27
027606   22  060006  02200006  000022  000032  000010  0     P       27
027606   22  060010  02200010  000022  000032  000010  0     P       27
027606   23  060000  02300000  000023  000033  000010  0     P       27
027606   23  060002  02300002  000023  000033  000010  0     P       27
027606   23  060004  02300004  000023  000033  000010  0     P       27
027606   23  060006  02300006  000023  000033  000010  0     P       27
027606   23  060010  02300010  000023  000033  000010  0     P       27
027606   24  060000  02400000  000024  000034  000010  0     P       27
027606   24  060002  02400002  000024  000034  000010  0     P       27
027606   24  060004  02400004  000024  000034  000010  0     P       27
027606   24  060006  02400006  000024  000034  000010  0     P       27
027606   24  060010  02400010  000024  000034  000010  0     P       27
027606   25  060000  02500000  000025  000035  000010  0     P       27
027606   25  060002  02500002  000025  000035  000010  0     P       27
027606   25  060004  02500004  000025  000035  000010  0     P       27
027606   25  060006  02500006  000025  000035  000010  0     P       27
027606   25  060010  02500010  000025  000035  000010  0     P       27
027606   26  060000  02600000  000026  000036  000010  0     P       27
027606   26  060002  02600002  000026  000036  000010  0     P       27
027606   26  060004  02600004  000026  000036  000010  0     P       27
027606   26  060006  02600006  000026  000036  000010  0     P       27
027606   26  060010  02600010  000026  000036  000010  0     P       27
027606   27  060000  02700000  000027  000037  000010  0     P       27
027606   27  060002  02700002  000027  000037  000010  0     P       27
027606   27  060004  02700004  000027  000037  000010  0     P       27
027606   27  060006  02700006  000027  000037  000010  0     P       27
027606   27  060010  02700010  000027  000037  000010  0     P       27
027606   30  060000  03000000  177747  177767  000020  0     P       27
027606   30  060002  03000002  177747  177767  000020  0     P       27
027606   30  060004  03000004  177747  177767  000020  0     P       27
027606   30  060006  03000006  177747  177767  000020  0     P       27
027606   30  060010  03000010  177747  177767  000020  0     P       27
027606   31  060000  03100000  177746  177766  000020  0     P       27
027606   31  060002  03100002  177746  177766  000020  0     P       27
027606   31  060004  03100004  177746  177766  000020  0     P       27
027606   31  060006  03100006  177746  177766  000020  0     P       27
027606   31  060010  03100010  177746  177766  000020  0     P       27
027606   32  06000


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