VAX 11/750 Config and Diagnostics, anyone?

J Blaser oldcpu2 at
Wed Nov 14 19:15:56 CST 2007

Just wanted to update everyone on the status of the Montpelier, Idaho 
VAX 11/750 that was rescued last month without much in the way of 
included modules, except for the Systems Industries 9700 
controller...and, to ask for some help.

After a little effort, I think I now have the minimum boardset required 
to fire this baby up.  But just to make sure that yours truly, a 
complete Unibus and  big-iron VAX noob, has it figured correctly, I 
wanted to run my configuration by you guys before I shoot off my right 
foot (which would, of course, leave me with only a wrong foot).

I've now got the following installed in the backplane:

<nothing> in CMI slot 1 (still looking for the optional L0001 FPU)
L0002 (DPM) in CMI slot 2
L0003 (MIC) in CMI slot 3
L0004 (UBI) in CMI slot 4
L0008 (PCS) in CMI slot 5
L0006 (RDM) in CMI slot 6 (optional, I guess, but came with other boards)
<nothing> in CMI slot 7 (I pulled the SI9700 from this slot)
<nothing> in CMI slot 8
<nothing> in CMI slot 9
L0016 (CMC2) in CMI slot 10

M8750 (1MB RAM) in 'extended' slots 11-18 (8MB total)

M9202 (Unibus 'joiner') in slots 19 and 20
M7485 (DZ11) in Unibus slot 21
<nothing> in Unibus slot 22
<nothing> in Unibus slot 23
<nothing> in Unibus slot 24
<nothing> in Unibus slot 25
<nothing> in Unibus slot 26
<nothing> in Unibus slot 27
M9313 (Unibus Term) in Unibus slot 28

I still don't have any mass storage interfaces (to support my RA81 
and/or x2 Fujitsu SuperEagles...still looking for UDA50, Dilog DU256, 
and/or Emulex UD33), but I was hoping that I have enough modules to 
start testing the CPU, anyway.

I do need to review Ethan's earlier comments about properly jumpering 
the now empty CMI slot 7, but I'll do that before I power up.

Does this look like a reasonable config for now, at least to start 
testing the CPU?


I have successfully cobbled a cable between the onboard TU58 drive 
(using external power) and a PDP-11/23+.  (Yes, I could have used a PC 
with John Wilson's PUTR, but the PDP was handy...the cable works either 
way.)  I have managed to image the four carts that were part of the 
rescue.  So at least I know that the TU58 is operational.  They're 
probably already 'out there', but for what it's worth, if anyone wants a 
copy of these images, let me know...

BE-CJ51E-BE VAX FORTRAN V4.4 BIN TU58 1/1 [help files, I think]
Systems Industries 9900 VAX/VMS Installation Package v4.0

After reading through the various docs found on and it appears that a standard set of TU58 DECtape II carts 
were included with each system.  Several of these carts contained CPU 
and system diagnostics.  I'm hoping someone has a set of these tapes 
imaged somewhere that I could download and give a try.

According to the VAX 11/750 HW Installation and Acceptance manual, the 
tapes with diagnostics are:

Tape 5:
- ECKAL - Cache/TB
- ECKAX - Cluster Exerciser
- ECKAM - Memory Diagnostic

Tape 6:
- ECSAA - Diagnostic Supervisor
- ECCBA - UBI/DW 750 Diagnostic

Tape 7:
- EVKAA - Hardcore Instructions

Tape 8:
- EVKAB - Architectural Instructions
- EVKAC - Floating-Point Instructions
- EVKAD - Compatibility Mode Instructions
- EVKAE - Privileged Architectural Instructions

Can anyone help me out?


- Jared

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