Mystery LSI-11 board

Paul Koning pkoning at
Wed Aug 24 12:34:26 CDT 2005

>>>>> "tom" == tom ponsford <tponsford at> writes:

 >>> That's definitely not a DEC board. For one thing, a Qbus board
 >>> wouldn't have gray handles, it would have maroon handles (that's
 >>> what the M in board part numbers refers to).

 tom> Well this is a qbus board as it came out of a qbus chassis and
 tom> the grey handles do have DEC on them! But I agree I think this
 tom> may be a third party/prototype board! However there is an
 tom> assembly number and other production artifacts that lead me to
 tom> believe this is not a prototype board in the strict sense.

One possibility is that it's a third party board with handles
manufactured by DEC attached to them.  DEC sold those handles
separately, and you could just attach them to your own board...

Something to check is whether there's a module number on them.
Standard DEC practice is to stamp the module number on the handle.
Module numbers are normally a letter plus 3 or 4 digits; the letter
matches the color:  M-maroon, W-white, G-green, R-red, and probably
others.  M were the later ones, with ICs on them (as opposed to R
which have either discrete transistors or, maybe, small scale TTL).
So the M series module codes includes large modules with cast metal
handles, as used in big VAXen.  Those aren't actually maroon in color
(more like grayish metal), but they still have the ID on the handle.

Yet another thing to look for: DEC boards have a DEC logo ("digital"
in 7 blocks -- unless it's quite old) somewhere on the board, almost
certainly near the edge. 


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