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
25 Jul
25 Jul
5:09 p.m.
On Jul 25, 2016, at 8:03 PM, Michael Thompson
<michael.99.thompson at gmail.com> wrote:
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.
DECtapes record everything twice (5 logical tracks, 10 physical tracks). Are there 10
coils or only 5? If 10, does the redundancy work well enough?
paul
5 Aug
5 Aug
1:41 p.m.
I have a linctape drive, which is a dectape compatible unit. I do not have
the controller or any documentation, but it does have a head which might be
useable to replace the broken head. If this would be useful, I would be
willing to contribute it to the cause.
Please see attached pics.
--tom
On 7/25/16 7:03 PM, Michael Thompson wrote:
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.
6 Aug
6 Aug
9:58 a.m.
On Fri, Aug 05, 2016 at 03:41:32PM -0500, Tom Uban wrote:
I have a linctape drive, which is a dectape compatible
unit. I do not have
the controller or any documentation, but it does have a head which might be
useable to replace the broken head. If this would be useful, I would be
willing to contribute it to the cause.
Please don't scavenge a LINCtape. it would be more valuable on a LINC or PDP-12 which
are
must rarer.
Please see attached pics.
The list strips pics. Send separately or put on the web.
/P
--tom
On 7/25/16 7:03 PM, Michael Thompson wrote:
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.
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