25 Jul
2016
25 Jul
'16
5:03 p.m.
During our PDP-12 debugging today we found that the left tape head has an
open coil for data track 0. The left head was OK a little more than a year
ago when we found the open coil in the right head. One TU56 head on my
personal PDP-8/e also had an open coil when I got it.
Our guess is the chemicals from the epoxy potting, possible flux residue,
and poor soldering are causing the failures. Getting the epoxy potting out
to repair the solder connection has proved impossible so far.
Any source for three TU56 tape heads would be appreciated.
We are also interested in ideas on how to get the epoxy potting out without
destroying the head.
--
Michael Thompson