23 Jul
2013
23 Jul
'13
6:27 a.m.
I have 2 HP 7906 drives and both are suffering from bad bearings.
Does anyone know, if the spindle motors can be taken apart, and how..
-Rik
24 Jul
24 Jul
1:54 a.m.
On Tue, 23 Jul 2013, Rik Bos wrote:
I have 2 HP 7906 drives and both are suffering from
bad bearings.
My experience with 7905 and 7906 drives is that if you run them for some
time (several hours), the noise will go away almost completely. But it
might be different in your case.
Christian
3:01 a.m.
-----Oorspronkelijk bericht-----
Van: cctalk-bounces at classiccmp.org [mailto:cctalk-bounces at classiccmp.org]
Namens Christian Corti
Verzonden: woensdag 24 juli 2013 10:54
Aan: General Discussion: On-Topic and Off-Topic Posts
Onderwerp: Re: HP 7906 spindle motor repair ??
On Tue, 23 Jul 2013, Rik Bos wrote:
time
I have 2 HP 7906 drives and both are suffering
from bad bearings.
My experience with 7905 and 7906 drives is that if you run them for some (several hours), the noise will go away almost
completely. But it might be
different in your case.
Christian
Christian,
Thanks for the advice, why should it be different ?
Removing the coil connection and a little tampering with the control lines
should keep the drive on.
But you of cause do own a DSU unit, which makes live a lot easier...
Am I right ?
-Rik
3:43 a.m.
On Wed, 24 Jul 2013, Rik Bos wrote:
Thanks for the advice, why should it be different ?
Well, our drives made terrible noises when they spun up the first time
after many years. My first thought was bad bearings (singing and
screaking like old HDDs), but otherwise the drives worked fine, so I just
ignored (and somehow even enjoyed ;-)) the noise. But the noise went away
after a few hours of running, so I think the bearings (the grease or
whatever) have "recovered" from sitting there unused for such a long time.
But it may be possible that you really have bad bearings or a bad motor.
Removing the coil connection and a little tampering
with the control lines
should keep the drive on.
But you of cause do own a DSU unit, which makes live a lot easier...
Am I right ?
What is a DSU unit? But no, I used the drive normally, attached to out
HP1000/2100 system.
Christian
5 a.m.
-----Oorspronkelijk bericht-----
Van: cctalk-bounces at classiccmp.org [mailto:cctalk-bounces at classiccmp.org]
Namens Christian Corti
Verzonden: woensdag 24 juli 2013 12:43
Aan: General Discussion: On-Topic and Off-Topic Posts
Onderwerp: RE: HP 7906 spindle motor repair ??
On Wed, 24 Jul 2013, Rik Bos wrote:
after many
Thanks for the advice, why should it be different
?
Well, our drives made terrible noises when they spun up the first time years. My first thought was bad bearings (singing and
screaking like old
HDDs),
but otherwise the drives worked fine, so I just
ignored (and somehow even
enjoyed ;-)) the noise. But the noise went away after a few hours of
running, so I
think the bearings (the grease or
whatever) have "recovered" from sitting there unused for such a long time.
But it may be possible that you really have bad bearings or a bad motor.
DSU is disc service unit as referred in the service manual.
http://www.hpmuseum.net/display_item.php?hw=743
One disc had a head crach, I've to look in that I have a set of spare heads.
The other one makes a lot of noise heads inspects ok, I'm afraid the
vibration caused by the spindle motor causes a head crash.
So I'm going to let it run with the heads retracted, by fooling the control
board and see what's happening.
Did you take other precautions to prevent the disc from ruining itself?
-Rik
Removing the coil connection and a little
tampering with the control
lines should keep the drive on.
But you of cause do own a DSU unit, which makes live a lot easier...
Am I right ?
What is a DSU unit? But no, I used the drive normally, attached to out
HP1000/2100 system.
Christian
3:13 p.m.
-----Oorspronkelijk bericht-----
Van: cctalk-bounces at classiccmp.org [mailto:cctalk-bounces at classiccmp.org]
Namens Rik Bos
Verzonden: woensdag 24 juli 2013 14:01
Aan: 'General Discussion: On-Topic and Off-Topic Posts'
Onderwerp: RE: HP 7906 spindle motor repair ??
time.
-----Oorspronkelijk bericht-----
Van: cctalk-bounces at classiccmp.org
[mailto:cctalk-bounces at classiccmp.org]
Namens Christian Corti
Verzonden: woensdag 24 juli 2013 12:43
Aan: General Discussion: On-Topic and Off-Topic Posts
Onderwerp: RE: HP 7906 spindle motor repair ??
On Wed, 24 Jul 2013, Rik Bos wrote:
after many
Thanks for the advice, why should it be different
?
Well, our drives made terrible noises when they spun up the first time years. My first thought was bad bearings (singing
and screaking like
old
HDDs),
but otherwise the drives worked fine, so I just
ignored (and somehow
even enjoyed ;-)) the noise. But the noise went away after a few hours
of
running, so I
> think the bearings (the grease or
> whatever) have "recovered" from sitting there unused for such a long
But it may be
possible that you really have bad bearings or a bad motor.
DSU is disc service unit as referred in the service manual.
http://www.hpmuseum.net/display_item.php?hw=743
One disc had a head crach, I've to look in that I have a set of spare Removing the coil connection and a little
tampering with the control
lines should keep the drive on.
But you of cause do own a DSU unit, which makes live a lot easier...
Am I right ?
What is a DSU unit? But no, I used the drive normally, attached to out
HP1000/2100 system.
Christian The other one makes a lot of noise heads inspects ok,
I'm afraid the
vibration
caused by the spindle motor causes a head crash.
So I'm going to let it run with the heads retracted, by fooling the
control
board
and see what's happening.
Did you take other precautions to prevent the disc from ruining itself?
-Rik
Small update I tied the /RS line (Run spindle) to the ground, I also
disconnected the voice coil so the heads stay retracted for the moment.
The /RS line comes from U65 (LS04) pin2 on the control board, I removed the
pin form the hole and made a wire to ground.
The disc is running at the moment, and screaming and making other noises.
I will let it run for a time and look what's happening.
Tomorrow I'll look at the earth strip.
-Rik
1:43 p.m.
Well, our drives made terrible noises when they spun
up the first time
after many years. My first thought was bad bearings (singing and
screaking like old HDDs), but otherwise the drives worked fine, so I just
ignored (and somehow even enjoyed ;-)) the noise. But the noise went away
after a few hours of running, so I think the bearings (the grease or
whatever) have "recovered" from sitting there unused for such a long time.
But it may be possible that you really have bad bearings or a bad motor.
I am totally cleueless about THOSE drives, but, 25+ years ago, a lot of
hard drives would squeal or shriek from the pad rubbing on the end of the
spindle.
Pressing it harder against the spindle would sometimes work, but not for
very long.
Some people would pry it away, or rip it off!
But, in most cases, deforming it slightly to move it SIDEWAYS a tiny
fraction of a mm would let it get started on a new wear spot, and silence
it for years.
25 Jul
25 Jul
12:58 p.m.
Well, our drives made terrible noises when they
spun up the first time
after many years. My first thought was bad bearings (singing and
screaking like old HDDs), but otherwise the drives worked fine, so I just
ignored (and somehow even enjoyed ;-)) the noise. But the noise went away
after a few hours of running, so I think the bearings (the grease or
whatever) have "recovered" from sitting there unused for such a long time.
But it may be possible that you really have bad bearings or a bad motor.
I am totally cleueless about THOSE drives, but, 25+ years ago, a lot of
2:28 p.m.
-----Oorspronkelijk bericht-----
Van: cctalk-bounces at classiccmp.org [mailto:cctalk-bounces at classiccmp.org]
Namens Tony Duell
Verzonden: donderdag 25 juli 2013 21:58
Aan: cctalk at classiccmp.org
Onderwerp: Re: HP 7906 spindle motor repair ??
>
> > Well, our drives made terrible noises when they spun up the first
> > time after many years. My first thought was bad bearings (singing
> > and screaking like old HDDs), but otherwise the drives worked fine,
> > so I just ignored (and somehow even enjoyed ;-)) the noise. But the
> > noise went away after a few hours of running, so I think the
> > bearings (the grease or
> > whatever) have "recovered" from sitting there unused for such a long
time.
> > But it may be possible that you really have
bad bearings or a bad
motor.
I am totally cleueless about THOSE drives, but, 25+ years ago, a lot
of
So am I.
I looked at the information on the Australian museum site. When I looked he photos of the drive with the covers off I saw a
normal-looking
induction
motor alongisde the disk housing nad thought
'what's the problem, jsut
remove
the through-bolts nad it'll come apart'. Alas
upon reading the manual i
realised
that this was the blower motor and that the spindle is
driectly driven by
a
brushless DC motor.
And now a word of warning. Those spindle assemblies are not designed to
come
apaert. They will ahve been assembled with a press
using special die
tools. There
may not even be a a way to strip it without damaging
some paet (that is,
theyre
may be no way to apply the force needed where it is
needed). Certainly the
belt-
driven spindles in some older drives are like that.
The next thing is that there may well be a dust seal in the assembly. And
it
woun't be a conventional seal, it could well be a
special magnet keepign a
ferrofluid between the housing and the shaft. Sorting that out could prove
'interesting' too.
-tony
On Christians advice I let the disc run for a few hours, at first without
the disc pack later with a disc pack in place.
After some time the noise faded away, and the spindle motor is running fine
now, it makes some noise but no vibration any more.
Next thing to do is inspecting the platters for corrosion and other nasty
things..
So at this time I'm not going to dismantle a spindle motor..
-Rik
30 Jul
30 Jul
6:17 a.m.
I've placed some pictures of the dismantled HP 7906 on Flickr, it's work in
progress I'm cleaning it to get it back in good working order.
http://www.flickr.com/photos/hp-fix/sets/72157634861063988/
-Rik
On Christians advice I let the disc run for a few
hours, at first without
the disc
pack later with a disc pack in place.
After some time the noise faded away, and the spindle motor is running
fine
now, it makes some noise but no vibration any more.
Next thing to do is inspecting the platters for corrosion and other nasty
things..
So at this time I'm not going to dismantle a
spindle motor..
-Rik
7:12 a.m.
Hey Rik,
very cool ! Thanks for sharing these nice pictures !
Pierre
?
-------------------------------------------------------------------------------
Pierre's collection of classic computers : http://classic-computing.dyndns.org/
________________________________
Von: Rik Bos <hp-fix at xs4all.nl>
An: 'General Discussion: On-Topic and Off-Topic Posts' <cctalk at
classiccmp.org>
Gesendet: 15:17 Dienstag, 30.Juli 2013
Betreff: RE: HP 7906 spindle motor repair ??
I've placed some pictures of the dismantled HP 7906 on Flickr, it's work in
progress I'm cleaning it to get it back in good working order.
http://www.flickr.com/photos/hp-fix/sets/72157634861063988/
-Rik
On Christians advice I let the disc run for a few
hours, at first without
the disc
pack later with a disc pack in place.
After some time the noise faded away, and the spindle motor is running
fine
now, it makes some noise but no vibration any
more.
Next thing to do is inspecting the platters for corrosion and other nasty
things..
So at this time I'm not going to dismantle a
spindle motor..
-Rik
7:34 a.m.
More is coming..
-Rik
-----Oorspronkelijk bericht-----
Van: cctalk-bounces at classiccmp.org [mailto:cctalk-bounces at classiccmp.org]
Namens P Gebhardt
Verzonden: dinsdag 30 juli 2013 16:13
Aan: General Discussion: On-Topic and Off-Topic Posts
Onderwerp: Re: HP 7906 spindle motor repair ??
Hey Rik,
very cool ! Thanks for sharing these nice pictures !
Pierre
----------------------------------------------------------------------------
---
Pierre's collection of classic computers :
http://classic-computing.dyndns.org/
>________________________________
> Von: Rik Bos <hp-fix at xs4all.nl>
>An: 'General Discussion: On-Topic and Off-Topic Posts'
><cctalk at classiccmp.org>
>Gesendet: 15:17 Dienstag, 30.Juli 2013
>Betreff: RE: HP 7906 spindle motor repair ??
>
>
>I've placed some pictures of the dismantled HP 7906 on Flickr, it's
>work in progress I'm cleaning it to get it back in good working order.
>http://www.flickr.com/photos/hp-fix/sets/72157634861063988/
>
>-Rik
>
>> On Christians advice I let the disc run for a few hours, at first
>> without
>the disc
>> pack later with a disc pack in place.
>> After some time the noise faded away, and the spindle motor is
>> running
>fine
>> now, it makes some noise but no vibration any more.
>> Next thing to do is inspecting the platters for corrosion and other
>> nasty
>things..
>> So at this time I'm not going to dismantle a spindle motor..
>>
>> -Rik
>>
>
>
>
>
>
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ard＠p850ug1.demon.co.uk -
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