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From: wtm@neoucom.UUCP (Bill Mayhew)
Newsgroups: comp.sys.cbm
Subject: Re: CBM 1541 alignment info requested
Message-ID: <341@neoucom.UUCP>
Date: Wed, 24-Dec-86 11:00:12 EST
Article-I.D.: neoucom.341
Posted: Wed Dec 24 11:00:12 1986
Date-Received: Sat, 27-Dec-86 00:38:41 EST
References: <1750@homxc.UUCP> <60006@ui3.UUCP> <229@uwslh.UUCP>
Organization: Northeastern Ohio Universities College of Medicine
Lines: 48
Summary: The pulley on the stepper motor is the culprit


Hi,

There is a steel band that moves the head carriage back and forth
in a 1541 disk drive.  The band is attached to a small pulley on
the shaft of a stepper motor located near the rear of the drive.
On the older dirves (I don't know about the newer ones), the pulley
was pressed on the shaft and NOT secured by set screws or the like.

One or more commonly available books contian descriptions on how to
drill a hole through the pulley and shaft, then insert a pin to
prevent the pulley from slipping on the shaft.

The usual problem that causes misalignment is stupid software
(usually copy-proofed) that forgets how many tracks it has moved
the head and keeps trying to turn the stepper motor, eventhough the
head is upagainst the stop after track 35.  In one case the
pirating (er... backing up) program, Disector, tried to step to
track 36 on my Parent's machine, thus causing a minor alignment
gaffe.

I think that the book, _Inside the 1541 DOS_, is one that contains
the information on how to realign your drive.  It has a short basic
program for the purpose.  It is possible to do so without special
tools, as the c64 itself can tell you if it is reading the diskette
correctly.  It will take patience though, as it is an iterative
process to get the alignment correct.  You'll also need to have a
diskette that was formatted on a machine whose alignment you trust
(or at least you want to be compatible with).

If you don't feel pretty self-confident and know at least a little
about how a drive works, it is probably best to let a shop do the
job for you, as $39-49 is a lot less than ~$200 if you screw up
your drive.

If anybody is worried about the exact title of the book, send me an
email, and I'll get it for you.  It's readily available since I got
a copy at Walden Books.

  --Bill

Bill Mayhew
Division of Basic Medical Sciences
Northeastern Ohio Universities' College of Medicine
Rootstown (really!), OH  44272  USA    phone:  216-325-2511
(wtm@neoucom.UUCP    ...!cbatt!neoucom!wtm)

By the way, Happy Holidays  (nondenominational message).