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Hi!

I have a SS10 with ca. 39MHz running 24/7 for 2 years now. In this time I
completly blown up two IBM DCAS Harddrives one after another. The circuit
board on the HD got allways a short circuit at a specific component near
the power connector. There is also a SMD fuse melted/burned away from the
other side of the circuit board. And the whole part is realy extremly ugly
smelling! The SS10 power supply was allways switching of, so there is no
further damage than the HD.

The question is: "Who is guilty, IBM DCAS or SS10 power supply?" Does
anyone has similar experience with burned HDs in a SS10?



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"Hans Surst" <aboo2@pluto.kww.bauing.tu-darmstadt.de> wrote in message
newspsknc3pt5u0ag4h@news.cis.dfn.de...
>
> The question is: "Who is guilty, IBM DCAS or SS10 power supply?" Does
> anyone has similar experience with burned HDs in a SS10?

Well, I have used a couple of SS5 and SS20's, and have never experienced
burned HDs. You need to make sure a couple of things though:
- keep the machine clean and dust-free
- don't run it without the cover, as this disturbs the airflow
- make sure that the power supply fans work properly, and the little fan
that is mounted close to the drive bays still works
- when using disks that tend to run hot (as most 10K rpm or faster disks
do), use only one disk

Hope this helps. Best regards,

Derkjan

On Sat, 15 Jan 2005 21:23:11 +0100, Derkjan <derkjan@haanjdj.demon.nl>
wrote:


>> The question is: "Who is guilty, IBM DCAS or SS10 power supply?" Does
>> anyone has similar experience with burned HDs in a SS10?
>
> Well, I have used a couple of SS5 and SS20's, and have never experienced
> burned HDs. You need to make sure a couple of things though:
> - keep the machine clean and dust-free
> - don't run it without the cover, as this disturbs the airflow
> - make sure that the power supply fans work properly, and the little fan
> that is mounted close to the drive bays still works
> - when using disks that tend to run hot (as most 10K rpm or faster disks
> do), use only one disk

The machine is clean, allways running with it's cover on it, all fans are
working... But all components are 7-10 years old including the DCAS
(5400rpm) which BTW runs very cool and silent. Electronic parts don't run
forever :-(


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All my spammers die in horrible pains!

Hans Surst wrote:

|> I have a SS10 with ca. 39MHz running 24/7 for 2 years now. In this time I
|> completly blown up two IBM DCAS Harddrives one after another. The circuit
|> board on the HD got allways a short circuit at a specific component near
|> the power connector. There is also a SMD fuse melted/burned away from the
|> other side of the circuit board. And the whole part is realy extremly ugly
|> smelling! The SS10 power supply was allways switching of, so there is no
|> further damage than the HD.

On the SS10's internal SCSI bus, the TERMPWR (terminator power) line is
connected to ground. Any disk that insists on providing terminator power
to the SCSI bus will cause problems. The usual symptom is some strange
and misleading OpenBOOT error message when trying to boot from that disk.

Some IBMs (in my case, a DPES 31080) fall into this category.

Solutions:
- Put the disk into an external enclosure, or
- Unsolder and bend up the TERMPWR pin on the disk's PCB.

--

"I'm a doctor, not a mechanic." Dr Leonard McCoy <mccoy@ncc1701.starfleet.fed>
"I'm a mechanic, not a doctor." Volker Borchert <v_borchert@despammed.com>

On 16 Jan 2005 03:20:35 GMT, Volker Borchert <v_borchert@despammed.com>
wrote:

> On the SS10's internal SCSI bus, the TERMPWR (terminator power) line is
> connected to ground. Any disk that insists on providing terminator power
> to the SCSI bus will cause problems. The usual symptom is some strange
> and misleading OpenBOOT error message when trying to boot from that disk.
>
> Some IBMs (in my case, a DPES 31080) fall into this category.
>
> Solutions:
> - Put the disk into an external enclosure, or
> - Unsolder and bend up the TERMPWR pin on the disk's PCB.

This maybe the case with the DCAS too, TERMPWR is never realy mentioned in
the 300pages spec book of this drive, there isn't a jumper for it anywhere
too. But I never had any problems booting or detecting DCAS drives in
SS10. If there is a problem with TERMPWR then there need to be exist a
bigger flow of current driving one of the small smd parts of the DCAS bad
over time. This would be an explanation, but I don't know if this is
possible in this case.




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All my spammers die in horrible pains!