VAX 780 on eBay

Jon Elson elson at
Sat Jan 1 16:33:02 CST 2022

On 1/1/22 3:19 PM, Josh Dersch via cctalk wrote:
> For clarification -- the 11/780 is not liquid cooled.  The seller mixed up
> some photos between the TU77 listing and the 11/780 listing (the TU77
> listing has photos of the 11/780's backplane in it just to make things more
> fun).  Agreed on all other counts, though, powering this thing up blindly
> is a dumb idea.
Right!  The cooling gear on the back of the TU77 is to cool 
the bearing air, to keep from melting the tape.  We had 
nasty tape sticking when running backups with our original 
TU77.  DEC told us about the problem and advised to open the 
cabinet back door when running the drive for long periods.  
Then, they installed a mod kit with the extra tubes and 
radiator and additional fans, and that solved the issue.

The VAX 11/780 is most certainly air-cooled, but does have 
impressive centrifugal blowers shooting vast quantities of 
air out the back.  Watch out, women with short skirts, when 
you walk behind the CPU!

DEC apparently designed a liquid-cooled VAX code-named 
Aquarius, but it was never fielded.  A later air-cooled 
version was called Aridus.


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