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From: "Ian Buckner"
Subject: Re: Hard drive spins with variable speed ... phase damage????
Date: Wed, 4 Dec 2002 11:02:54 -0000
Organization: Agilent Technologies
References: <firstname.lastname@example.org> <3DED2C94.311EEDA9@webaccess.net>
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"Chuck Simmons" wrote in message
> I need to rescue the data of a SCSI drive (Quantum Viking II 9.1GB
> 7200 rpm). It seems the disk has a problem with the motor because I
> can hear it spinning at one speed and then it slows down to another
> speed, and then again it goes up, and then down again. From what I
> have read it could be that one of the motor phases have damage, and
> thats why the motor canīt reach itīs 7200 rpm.
> To open the drive I can use a laminar clean bench at my university.
> doubt is the following: Can I speed the motor myself with another
> and make the disk reach the 7200 rpm and then make an image of the
> drive to another disk? Is that possible? Should the disk spin at
> rpm exactly ?? or will it work at 7000rpm or 7500rpm for example??
> Thanks for your time, I appreciate any help.
> Sorry for my english but it is not my native language. (I am from
> Nicolas Mella
A little information. BTW, I was never a spindle guy until I got into
optical so I know less about trends in spindle control.
- Does the spindle motor have three wires or does it have 8 or more?
- Can you look at the phases with an oscilloscope? If they all look
alike, the motor and driver are probably OK.
- Given you can do the above, what is the maximum frequency you see on
one phase? I won't hazard a guess because I have no clue how many
the motor has (I'm kind of used to 12 pole motors right now).
- Can you hear the head actuator come out of latch (depending on latch
design, this may be subtle)?
- Is there any scraping noise at all when the drive is powered?
... The times have been,
That, when the brains were out,
the man would die. ... Macbeth
Chuck Simmons email@example.com
Good questions from Chuck.
A remote possibility would be to change the orientation of the drive,
to change the loading on the spindle. Hard drives are designed to
both when horizonal and vertical, I'm not sure about inverted
If that makes a difference, you probably have only a short time to get
the data off the disk.
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