DECTape head problem - test-drb@ccmp.vtda.org

7 Feb 2022

DECtapes have 5x redundant tracks. If you could find an 8-track head that
had the same track pitch, and maybe track width, you could read the tape
but lose redundancy on the Mark and Timing tracks. That probably would not
work with a marginal DECtape.

On Mon, Feb 7, 2022 at 3:33 PM Wayne S <wayne.sudol at hotmail.com> wrote:

...
  I?ve often wondered if the tape heads from consumer
tape devices such as
 cassette or 4-8 track tape players could be used or be made to be used as
 replacements. Anybody ever try that?

 Sent from my iPhone

  On Feb 7, 2022, at 11:51, Michael Thompson via
cctech <  cctech at classiccmp.org> wrote:

 ?

 From: Gary Oliver <go at aerodesic.com>
 Subject: DECTape head problem

 In debugging my DECtape interface lashup, I found that one of my head
 has two open windings.? Specifically, one channel has an open 'ground'
 with the other two lines apparently the full winding of the channel.?
 The second channel failing has no continuity between any of the three
 lines.? I have tested the other head and it has all the requisite
 continuity so I'm hoping I can at least get a single spindle running.

 Has any ever attempted repair of one of these?

 -Gary

 At the Rhode Island Computer Museum we found several DECtape heads on  TU55
  and TU56 drives with open connections. A
volunteer got one head X-Rayed  so
  we could see the solder joints between the tiny
wires for the head coils,
 and the larger twinax wires that go to the relay board. We couldn't see  any
  damage to the wires or solder joints.

 We tried heating the potting material to soften it, and digging it out to
 get to the solder joints. While digging at the potting material you can't
 see the tiny wires, so they will likely get damaged.

 We considered using a solvent to remove the potting material, but thought
 that it would eat the enamel off the head coil wires and damage them  beyond
  repair.

 So far we haven't found a way to repair the heads.

 Michael Thompson 

-- 
Michael Thompson