MicroVAX II problem

John Willis willisjo at zianet.com
Thu Mar 3 23:29:34 CST 2005

Hello all,

I purchased a MicroVAX II about a year ago. When I went to
the office where it was sitting, the original owner, a former
DEC field service engineer, and myself powered the machine up.
VMS came up successfully; no problems there. The system is in
a BA23 rackmount chassis, and contains a MOB Systems quniverter,
to connect it to a BA11K Unibus chassis via two large ribbon
cables. The system contains also the following boards:

M7658 - 16-bit parallel I/O with DMA and block mode functions
M3104 - DHV11-A 8-line asynchronous DMA MUX
M7651 - 18/22-bit DMA general purpose parallel interface

Also, a TQK50 TMSCP controller and an RQDX3 ST-506 MSCP controller.
The system has for drives an RD54 fixed disk and a TK50 tape drive.

Anyhow, once I got the system home and cabled everything back according
to the notes/pictures taken of the original installation, the system
would not come up, and the DC OK light on the front panel would not
light. I checked and re-checked the cable connections, re-seated all the
boards, still no-go.

Realizing I would not need the Unibus chassis, as it contained no cards
other than the one needed to connect it to the uVAX II's Qbus, I removed
the Qbus part of the quniverter. This solved the DC OK problem, and the
system would actually begin its power-on tests (F...E...D...C... etc.),
however, it hangs at 3. From what I could find in DEC documentation,
this is a "spurious interrupt" problem, and the docs gave no clue as to
how to go about tracking it down to any specific part of the system.

I have tried pulling all the cards except for CPU and memory, to no avail.
I tried installing the RD54 in a VAXstation 2000. It boots VMS successfully
when installed in that system, so I know the drive is good.

Unfortunately, I recently moved and could not keep the BA11K due to
space constraints, so I have since parted with that chassis.

I'm completely stumped at this point. Any suggestions?

Thanks much,

John Willis

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