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From: esmith@apple.com (Eric Smith)
Newsgroups: comp.sys.mac.hardware
Subject: Re: Floppy infinite eject problem
Message-ID: <8618@goofy.Apple.COM>
Date: 8 Jun 90 00:43:04 GMT
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Sender: usenet@Apple.COM
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In article <9848@lindy.Stanford.EDU> simoni@strat.stanford.edu writes:
>I have been trying to connect an 800K Sony floppy disk drive up to the
>external drive port of a Mac Plus.  When I turn on the computer the disk
>drive immediately begins to infinitely cycle through its eject sequence.

Disclaimer:  I work for Apple, but my job has nothing to do with disk
drive hardware.  I discovered this information empirically prior to my
employment at Apple, in the process of getting an 800K drive to work on
a Lisa.

I believe that later revisions of the 800K drive (not sure about 1.4M
drives) use one of the signal lines of the 20 conductor ribbon cable as a
dedicated eject line (probably for use in the UniDisk 3.5).  That line was
formerly used as one of the power or ground lines.  Unfortunately, I'm not
sure which line it is.  Anyhow, if you cut that line the drive might work
correctly (it solved the problem for me).  If you look at the ribbon cable
Apple supplies with internal drives, that particular conductor is MISSING.
Just insulation, no copper.

Eric Smith
esmith@apple.com

Opinions expressed herein are not necessarily those of my
employer, family, friends, computer, or even me!  :-)