27 Jan
2011
27 Jan
'11
7:34 a.m.
On Wed, Jan 26, 2011 at 8:34 PM, Michael Thompson
<michael.99.thompson at gmail.com> wrote:
The tan ones might or might not be susceptible, but I think you are right that
the black housings are newer and manufactured past that point (I've never
owned one that new).
My recollection of observing RA81 data is that it generates enough traffic
that it's worth having 80x25 if you have room for a full-sized terminal.
A quick check, but important.
The motors start to spin up, accelerate for a few
seconds and then
stop. A few years ago I fixed and RA81 that had the same symptoms by
replacing the starting capacitor.
OK. I presented alternatives because in all the years I've been
working with RA81s, that wasn't a component I've ever had to replace
(but I've seen _plenty_ of RA81 faults).
RA81s were at
one point, exceedingly susceptible to HDA failure...
Two RA81s have tan colored HDAs, one has a black HDA. I think that the
black HDAs are the new design that doesn't crash so often. RA81 drives
have a DB25 inside. ?You can plug a terminal in and run
on-board diagnostics and monitor operations...
I forgot that I have a DEC Termiflex that plugs into the RA80/81 and
the TU81 diagnostic port. I will connect it to the drives this weekend
and see if I can get more details on the problem. Oh... just a
detail - you mention locked heads - you _did_ pull the
cord to retension the drive belt, right?
I saw the pull cable on the right side of the drive. I have used those
in the past to replace HDAs or motors. I will make sure that it was
not in a position to release tension on the drive. I looked at the 2.11BSD setup document and it says
that the TU81+ is a
supported tape drive.
Handy.
The M8739 KLESI-UA interface for the TU81+
doesn't seem to be
common or inexpensive. I think that the RCS/RI guys have one that I
could borrow for an installation.
The M8739 KLESI is the same as the one in a VAX-11/725, if you happen
to have one of those lying around.
It might be simpler to just use vtserver.
It most likely will be.
Thanks for all of the comments.
Happy to help. I've got my own 11/44 that I haven't done anything
with yet (it was a rescue) so it's a learning experience for me, too.
-ethan