cctalk Digest, Vol 13, Issue 24 - test-drb@ccmp.vtda.org

24 Jul 2015

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 Date: Thu, 23 Jul 2015 15:27:04 -0600
 From: Eric Smith <spacewar at gmail.com>
 Subject: Re: PDP 11 gear finally moved

 There's no artifact safety issue for the PDP-1 power supplies.  They
 use a ferroresonant transformer, rectifiers, and filter capacitors.
 If any of those fail, the machine won't work properly, but it won't be
 damaged.

The AC capacitor attached to the ferroresonant transformer can have a
spectacular failure mode where it hisses, sparks, and sprays (probably PCB
laden) oil on everything.  As you said, all that will happen is the output
voltage goes low and it probably blows a fuse.

-- 
Michael Thompson