3 Dec
2015
3 Dec
'15
1:05 p.m.
*sorry a copy went out prematurely...
So I got my hands on an HP 88780 1/2" Tape Drive from list Member Mark
(Thanks!). The drive physically looks to be in good shape but was pretty
dirty when I got it. I've cleaned up the drive and powered it up.
The good news:
The drive powers up. Initially I had trouble getting it to load a tape but
that seems to have been resolved. The BOT, EOT sensors are good and the
basic drive mechanism (motor, eject, etc.) seem to be working.
The bad news:
Some of the front panel buttons are not working. Running test 72 shows
failure in the unload/rewind and online buttons. Luckily it seems to be a
mechanical problem. If I short the switch on the circuit board then the test
passes. The switches are mechanical push buttons that are soldered on so
should be easy to replace. Anyone know of a good or OEM equivalent
replacement? If need be I can get pictures of the buttons off the PCB.
The worse news:
The tape drive will not read/write. I ran test 01 which per the service
manual does a full general checkout of the drive. The test is a conglomerate
of other test routines. It fails when it tries to run test 177 (Buffer Write
Density ID). This is where I am currently stock and need advice on how to
proceed.
Any help is appreciated. TIA
-Ali
3 Dec
3 Dec
1:27 p.m.
On Thu, Dec 3, 2015 at 1:05 PM, Ali <cctalk at fahimi.net> wrote:
So I got my hands on an HP 88780 1/2" Tape
Drive...
The bad news:
Some of the front panel buttons are not working. Running test 72 shows
failure in the unload/rewind and online buttons. Luckily it seems to be a
mechanical problem. If I short the switch on the circuit board then the test
passes. The switches are mechanical push buttons that are soldered on so
should be easy to replace. Anyone know of a good or OEM equivalent
replacement? If need be I can get pictures of the buttons off the PCB.
I have been recently cleaning and testing an HP 7980A. I also had
problems with some of the mechanical buttons, verified with TEST 72.
I was able to clean most of them with contact cleaner and agitation,
but the ONLINE button was stubborn. I ended up replacing it with a
generic 2-pin tactile switch. I do not know where to get OEM switches
of this exact type - they are somewhat taller than cheap tactile
switches, and appear to have a solid conductive rubber button/pad
instead of a plastic top and metal internals. My defective button has
a closed resistance measuring in multiple K ohms.
I would also love to hear of a source of replacement buttons of the
original style.
-ethan
1:45 p.m.
On Dec 3, 2015, at 10:05 , Ali <cctalk at
fahimi.net> wrote:
So I got my hands on an HP 88780 1/2" Tape Drive from list Member Mark
(Thanks!).
I bought that drive and a Kennedy 9610 (which I'm keeping for myself) at the recycler
who has the System/32. I saw them under a pile and snatched them immediately, hoping they
would be useful. Both ended up having SCSI interfaces. I haven't done much with my
Kennedy drive yet other than ordering a replacement power switch for it.
--
Mark J. Blair, NF6X <nf6x at nf6x.net>
http://www.nf6x.net/
4 Dec
4 Dec
10:34 a.m.
On 12/3/15 10:45 AM, Mark J. Blair wrote:
I haven't done much with my Kennedy drive yet
other than ordering a replacement power switch for it.
Keep an eye on the tach roller, the rubber degrades.
They are nice drives, but they spin fast and are not gentle on tapes.
When they work, they do pretty well on 800bpi media. There were a couple
of different revs of SCSI board, later ones have bigger buffers that
stream better. They also have the advantage over the 88780 that I was
able to find complete service manuals for them with schematics.
If people really get stuck for parts, I still have a few 88780s buried
in storage that I gave up on because I was promised a set of drawings that
came indirectly through some mysterious guy in Seattle, but I never got them.
11:58 a.m.
If people really get stuck for parts, I still have a
few 88780s buried
in storage that I gave up on because I was promised a set of drawings
that came indirectly through some mysterious guy in Seattle, but I
never got them.
Al,
If you have donor machines I am interested in some parts - specially the
read/write/format board. I will send you an email off list.
-Ali
9 Dec
9 Dec
2:10 p.m.
I am still looking for some help on this if anyone has ideas. It looks like
the read/write/format board is bad. Anyone have a spare they can part with
or are am I looking at a super effective door stop here?
-Ali
3148
days inactive
3155
days old
6 comments
5 participants
participants (5)
-
aek＠bitsavers.org -
cctalk＠fahimi.net -
dick＠tonkaland.com -
ethan.dicks＠gmail.com -
nf6x＠nf6x.net