DEC MicroVAX 3600

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This page captures what I have discovered so far in bringing up two MicroVAX 3600s.

As of 16 May 2017, I have only attempted to bring up one of the two 3600s. This one is a fairly ugly looking unit. It’s clearly been stored outdoors for some part of its life. It has leaf, rodent and corrosion damage inside the rear of the cabinet, as well as significant fading and disclouration of the front door. The machine has two RA90 drives mounted at the top of the cabinet. However, these have been fitted in a fairly amateurish manner (for example – there is no front panel in front of the two RA90s).

After thoroughly cleaning up this 3600, I was very surprised to find that it successfully booted up into VMS 5.5 from the left-hand RA90 on the very first attempt! Both RA90s initially squealed slightly for about the first 10 minutes, but the noise went away after that and they’ve been fine since. It sounded a little like fan-belt slip, though it was more likely to be bearing noise (I’ve been told there are no drive belts in the RA90 drives).

13 May 2017

I first powered up this 3600 on 13 May 2017. By issuing the “boot” command at the “>>>” prompt, it booted into VMS 5.5. I did not know the password for the SYSTEM account, so I was not able to progress much past this point.

The right-hand RA90 would not spin up (the Test light would light briefly, before going out and the Fault light coming on instead).

15 May 2017

Using the procedure outlined here, I was able to break into VMS and change the password for the SYSTEM account to MICROVAX.

The main steps taken to break into VMS and change the password are shown below:

>>> B/R5:40000001

SYSBOOT> SET/STARTUP OPA0:
SYSBOOT> SET WINDOW_SYSTEM 0
SYSBOOT> SET WRITESYSPARAMS 0
SYSBOOT> CONTINUE

$ DEFINE/SYSTEM/EXEC DECW$IGNORE_WORKSTATION TRUE
$ SPAWN
$ @SYS$SYSTEM:STARTUP

$ SET DEFAULT SYS$SYSTEM:
$ RUN SYS$SYSTEM:AUTHORIZE
UAF> MODIFY SYSTEM /PASSWORD=newpassword
UAF> EXIT
$

When we then logged in using the SYSTEM account and the new password, VMS informed us that the last login was in 1996!

Richard swapped a spare set of RA90 controller boards into the right-hand RA90 drive, and it now spins up and the Ready light comes on. I’ve not yet figured out how to access this drive within the VMS file system.

The NICAD battery pack was removed from both 3600s. Some minor corrosion was already evident, but not severe.

Next steps

Need to learn how to navigate to the second RA90 drive, to explore its contents.

Need to repair the rotary boot-selection switch (the tiny knob has broken off).

Need to source a replacement NICAD battery pack.

Links

MicroVAX 3500 documentation (not MicroVAX 3600, but close)