KRQ50/RRD40 problems

Robert Armstrong bob at
Sun Dec 17 20:12:53 CST 2006

  I've got a KRQ50 (M7552) and a RRD40-DC (the 15 pin LMSI version, not the
SCSI version!) drive in a MicroVAX-III, but I can't seem to get them
working.  VMS sees the KRQ50 as PUB0, but it doesn't see any drives on the
controller.  Any attempt to access DUB0 just gives device offline errors.
  I read somewhere that the KRB50 had to have a particular firmware version
before it would work with the RRD40 - does anybody know the correct ROMs
that I should have on my board?
  I didn't have a cable to connect the drive and controller, so I made one.
Is the cable just supposed to be a DB15M <-> DB15F with all pins wired
straight thru?  Is there anything special about the cable?
  Is there any significance to the A and B ports on the KRQ50 (i.e. does it
matter which one you use)?
  Unfortunately this seems to be a really rare device, and online docs are
pretty much non-existent.
Bob Armstrong

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