Strange DEC PC05 paper tape reader: doc for M705 needed

Jörg Hoppe j_hoppe at
Tue Jun 23 09:54:00 CDT 2015

Hi all,

I could acquire *four* rotten PC05 Papertape Reader/Punches for PDP-11.
I'm now restoring them.

One of these is strange:
Normally, the feed hole (between data hole 3 and 4) is used to clock in 
bits from the data holes.
But this very special PC05 does not have a phototransistor for the feed 
hole, so the data clock signal must be generated by the stepper motor 
Maybe it's a very old model: the READER CONTROL module is M705, not the 
usual M7050. And there's no doc for it.

Does anybody has a FPMS with schematics for the M705 modul? Perhaps as 
part of some PDP-8 doc?


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