Path: utzoo!attcan!uunet!cbmvax!sterling
From: sterling@cbmvax.UUCP (Rick Sterling QA)
Newsgroups: comp.sys.amiga
Subject: Re: A1000 Disk Drive Trouble
Message-ID: <3987@cbmvax.UUCP>
Date: 10 Jun 88 12:18:02 GMT
References: <4388@gryphon.CTS.COM>
Reply-To: sterling@cbmvax.UUCP (Rick Sterling QA)
Organization: Commodore Technology, West Chester, PA
Lines: 53

In article <4388@gryphon.CTS.COM> bilbo@pnet02.cts.com (Bill Daggett) writes:
> Over the last 1.5 years I have had a rare internal drive problem.
> All of a sudden a disk that has worked FINE when put into the internal drive
> (df0:) will make a "tick-like" sound at the rate of the disk speed (which I
> think is 300 rpm or so) and fail to WORK at all.  Info gives "Unreadable disk"
> and trying Dir gives the requester "Not a DOS disk" or some such.
> 
> When this disk is used in the external drive (df1:) it spins up nice and quiet
> and works fine.  Further more, another disk placed in the internal drive works
> fine too.  So, I suspect some dimensional change has occurred on the affected
> disk and that I have a dimensional difference somewhere in my floppy drives
> that amounts to this problem.  The "ticking-like" sound probably slows the
> disk speed or causes it to be erratic enough that nothing gets read.  I have
> been unable to determine EXACTLY what is rubing.  Since the affected disks
> work fine in my other drive and other disks work fine in the internal drive I
> put the internal drive at fault somehow.
> 
> The solution in the past (there have been about 3 previous disks that have
> acted up this same way in the last 1.5 years) has been to copy the data from
> the affected disk in the external drive to a good disk that works O.K. in the
> internal drive and throw the affected disk away.  HOWEVER, this last time it
> occurred on my Marble Madness disk which is copy protected and things aren't
> so simple.
> 
> Does anyone identify with this problem??  BTW, the drives are identical
> Matsushita JU-363-03 drives.  Is there something I can "tweek" in the affected
> drive to make it more forgiving??
> 
> Once the "tick-like" sound develops it does not mysteriously disappear. 
> Clearly something changed in the disk and something is more untolerant in the
> internal drive.
> 
> Thanks in advance for any knowledge you can throw to me about this.
> 
> Bill
> 

 The 'ticking' sound is most probably caused by the disk drive spindle pin
 failing to catch properly on the diskette's drive hub slot. Check for 
 foreign material in or on the diskette's metal hub and make sure the 
 diskette media turns freely. I've also seen an occasional diskette where the
 drive slot on the hub is not to spec and will cause the intermitant problems.

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   Rick Sterling             COMMODORE AMIGA TEST ENGINEERING
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