10 Jan
2004
10 Jan
'04
8:58 a.m.
Just been playing with some real DEC hardware today and trying to coax
some life out of a pair of RA81 drives.
Both drives are exhibiting the same fault - as soon as the RUN button is
hit they seem to try and spin up for a second or two before the spindle
motor disengages and the red FAULT light comes on.
I'm not back at the site where these are until next weekend now, but is
this a common fault that might mean there are a few obvious things I
should check first?
One drive was supposedly working when decomissioned at the site where it
ran; the other one was definitely running on the site I was at today the
last time it was powered up a short while ago. Curious that both of them
are showing the same fault.
I only had the RA81 user manual with me today - should be able to get
hold of the service manual for next weekend. However, I hooked a
terminal up to the diagnostic port on both drives. Issuing a "RUN DIAG"
command with the HDA offline shows all tests passed. Pressing the RUN
button as described in the manual gives the "Front panel function in
progress" message as expected, the drive tries to spin up and stops, the
fault light comes on, and I get dumped back to the RA81> prompt on the
terminal - it doesn't even try to run any of the diags that the manual
suggests it should do at this point.
Looks like something's overloading when the drive tries to spin up and
immediately shutting things down. The HDA is free to turn, belt tension
seems good, and the motor manages a few revolutions before it stops.
Unforunately I can't for the life of me remember what other lights came
on at the front of the drive along with the FAULT light :-(
cheers
Jules
10 Jan
10 Jan
11 a.m.
Just been playing with some real DEC hardware today and trying to coax
some life out of a pair of RA81 drives.
Both drives are exhibiting the same fault - as soon as the RUN button is
hit they seem to try and spin up for a second or two before the spindle
motor disengages and the red FAULT light comes on.
I'm not back at the site where these are until next weekend now, but is
this a common fault that might mean there are a few obvious things I
should check first?
One drive was supposedly working when decomissioned at the site where it
ran; the other one was definitely running on the site I was at today the
last time it was powered up a short while ago. Curious that both of them
are showing the same fault.
One quick question. Was the positioner locked before you moved the
drives, and have you unlocked it? There's a white lever on top of the HDA
at the front (in front of the R/W PCB). If you moved the drive without
locking it, you may well now be looking for a new HDA :-(
-tony
11:50 a.m.
One quick question. Was the positioner locked before
you moved the
drives, and have you unlocked it? There's a white lever on top of the HDA
at the front (in front of the R/W PCB). If you moved the drive without
locking it, you may well now be looking for a new HDA :-(
At least in the last couple of years they've been moved safely with the
lever in the locked position and the belt tensioner released, so that
*should* be ok. Of course, I don't know the history of the drives prior
to that. But at least one of them hasn't been moved since it was last
successfully run at the current site; it just gave this fault today when
we tried to power it up.
Whether the other unknown unit has more serious problems or not I won't
find out until later. Half the cables were unplugged inside suggesting
that *someone* had been monkeying around with it at some point.
Curious how they both give the same fault though.
I was doing a bit of googling and it seems like the motor start
capacitor and the HDA bearings (eek!) are possible culprits on units
that don't see a lot of use for an extended period of time.
Anyone know the specs of the motor run caps? If so I may have a suitable
one here that I can take with me next weekend and save some messing
around trying to find one on the day.
Anyone know if the bearings on these units at all servicable? I'd expect
not, but I suppose it's possible given their age and serviceability.
cheers
Jules
11 Jan
11 Jan
9:58 p.m.
On Sat, 2004-01-10 at 22:39, Jules Richardson wrote:
Anyone know if the bearings on these units at all
servicable? I'd expect
not, but I suppose it's possible given their age and serviceability.
cheers
Jules
I'd be surprised if you couldn't get the bearings out. You might even
be able to put it back together when you're done ;-)
I seem to recall, from taking apart very dead big DEC disk drives, that
the spindle ran in fairly boring ball races. If you get them out, you
can check for wear and play. There will be a code stamped on them that
you can use to order a replacement. Take it to your friendly
neighbourhood motor factor or specialist bearing stockist.
Gordon.
12 Jan
12 Jan
9:31 a.m.
I'd be surprised if you couldn't get the
bearings out. You might even
be able to put it back together when you're done ;-)
The problem is that the RA81 is a Winchester, and the spindle bearings
are part of the sealed HDA. Yes, you can take it apart, but without a
clean room you're not going to have a reliable drive at the end of it all.
-tony
16 Jan
16 Jan
1:37 a.m.
On Mon, 2004-01-12 at 20:31, Tony Duell wrote:
Ah, ok. Well, if it's broken *anyway*, you can hardly make it worse...
Gordon.
I'd be
surprised if you couldn't get the bearings out. You might even
be able to put it back together when you're done ;-)
The problem is that the RA81 is a Winchester, and the spindle bearings
are part of the sealed HDA. Yes, you can take it apart, but without a
clean room you're not going to have a reliable drive at the end of it all.
-tony
12:19 p.m.
Ah, ok. Well, if it's broken *anyway*, you can
hardly make it worse...
Wrong, you can make it considerably harder to repair properly in the
future!. Bearing replacment might be practical if you have a clean room,
but if somebody's already dismantled the HDA, got dust in it, and then
caused a headcrash, the final repair is going to be a lot harder!
-tony
11 Jan
11 Jan
12:10 p.m.
I only had the RA81 user manual with me today - should
be
able to get hold of the service manual for next weekend.
The RA82 User Guide has a table somewhere that lists what
the fault codes mean. I assume that the RA81 User Guide
also has such a table - if you scanned the manual and
made it available to use then we'd know for sure :-)
Same goes for the service guide ...
Antonio
--
---------------
Antonio Carlini arcarlini(a)iee.org
12 Jan
12 Jan
10:01 a.m.
On Sun, 2004-01-11 at 23:10, Antonio Carlini wrote:
It does... like I said I only realised that the front panel lights were
menaingful for diagnostics when I'd run out of time to play with things
- d'oh!
I did bring the manual home with me so have it here; but looking at the
table now I'm almost certainly going to be looking at a "Spin error"
when I get back on site next weekend. Nearly everything else I can
either rule out as either not being relevant at this point, or covered
by the diags I ran from the terminal.
I only had the
RA81 user manual with me today - should be
able to get hold of the service manual for next weekend.
The RA82 User Guide has a table somewhere that lists what
the fault codes mean. I assume that the RA81 User Guide
also has such a table - if you scanned the manual and
made it available to use then we'd know for sure :-)
Same goes for the service guide ...
When I posted the original message I actually expected a deluge of
replies with advice and pointers to websites that had the docs etc. :-)
If they seriously aren't online anywhere I could scan them at some point
and find a home for them. Just not right now as I'm a litle overwhelmed
with stuff at the moment!
cheers
Jules
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