Path: utzoo!utgpu!news-server.csri.toronto.edu!cs.utexas.edu!usc!jarthur!nntp-server.caltech.edu!toddpw
From: toddpw@nntp-server.caltech.edu (Todd P. Whitesel)
Newsgroups: comp.sys.apple2
Subject: Re: Help with my 5.25 drive
Message-ID: <1991Apr6.085456.19804@nntp-server.caltech.edu>
Date: 6 Apr 91 08:54:56 GMT
References: <29110018@hpfcdj.HP.COM>
Organization: California Institute of Technology, Pasadena
Lines: 18

jordan@hpfcdj.HP.COM (Steve J. Jordan) writes:

>wonder if it's trashing disks when I power-up & power-down my system with a 
>disk in the drive.  Do all 5.25 drives properly handle powerup/down?  (ie. the
>write-head should not be skipping around.)

This I can answer right away. If the drive motor isn't spinning, the disk
can't be modified -- IF the drive electronics are working properly. The
light should also only be on when the motor is actually running.

It is possible for the drive electronics to experience an age problem in
which they accidentally kick into write mode about 1/3 of the time they
are stepped to a new track. One of my friends had this problem in a cheap
mail-order drive he got five years ago; we had to replace the MC3470 to
fix it. (We swapped chips between drives to figure that out.)

Todd Whitesel
toddpw @ tybalt.caltech.edu