Unrecognized DEC Power Supply in PDP-11/44 Configuration

pbirkel at gmail.com pbirkel at gmail.com
Thu Dec 2 08:29:42 CST 2021

Does anyone recognize the (presumably) DEC power supply on the front half of
the rack-bottom in the 11/44 listing at:




Blurry photo, but it looks like there are a 4x3, a 3x3, and a 3x5 Molex
connector, and two brown mini-modules protruding from the right side.


If so, then what purpose did it likely serve?


It appears that the 6U immediately below the 11/44 was likely occupied by an
RX02 given the presence of an M8256 in the 11/44 backplane (and skinny
mounting rails, although I thought those were usually at the bottom of the
RX02), and that included its own power supply (which wasn't very beefy
either, nor did it need to be).


What went into the 6U immediately above the power supply is unclear; there
is a HEX Wespercorp TC130 Tape Controller as well as three unknown QUAD
modules in the 11/44 backplane.  Perhaps there was a horizontal autoload
tape drive mounted there that required a separate power supply?




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