In search of VAX 750 front door and CPU spares.

Henk Gooijen henk.gooijen at
Sun Apr 17 02:29:39 CDT 2016

-----Oorspronkelijk bericht----- 
From: Ian Finder
Sent: Sunday, April 17, 2016 1:23 AM
To: General Discussion: On-Topic and Off-Topic Posts
Subject: In search of VAX 750 front door and CPU spares.

Please let me know if you know of any. Picked up a 750 today, and will be 
making a trip to Calgary in a few months for another...

I also have a not complete VAX-11/750. I am looking for the rear cover.
Given its size, probably expensive to ship even within the EU, but if
somebody has that rear cover, I'd love to hear!

My VAX-11/750 *was* working ... I powered it up regularly, but as the
temperature in my "Hall of Famous Iron" is just 10 degrees Celsius,
I figured that grease of bearings in the disk drives are not that
viscous. So I am waiting for warmer times. Anyway, a fortnight ago,
I had read in the installation manual that a certain revision level
is required for the FP option (slot 1). I have that FP board, but I
never installed it, because it is a "little oven", so much heat is
generated by this board. The manual also said how to see the revision
level, so I turned on the VAX and entered the command (E/I 3E, IIRC).
My vax is of a higher revision level so that was good. But I smelled
something "funny" ...
Looking at the back side I saw dense smoke coming out of the power
controller! Quickly switched of the machine, and returned to the back.
The smoke came out the opening where the mains cable goes in. The smell
gave me the impression it was like slow-burning cigarette paper, not
the typical smell of a over-heated resistor.
I have good hopes that the H74** PSUs are fine, and that capacitors in
the mains filter died. But that remains to be seen.
A quick look how to remove the power controller was not obvious, so I
have to grab the documentation. Need it anyway.

The accompanying RA81 (with on it the VAX diagnostics) did not start up
correctly, but that was a simple head lock issue ... After some years
I even had forgotten how to open the RA81! But that RA81 now starts up
fine and lights the READY indicator. I updated the RA81 web page a bit.
Two steps forward, one step back ...

- Henk

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