Article 125 of comp.binaries.cbm:
Xref: watserv2.uwaterloo.ca comp.binaries.cbm:125
Path: watserv2.uwaterloo.ca!torn!spool.mu.edu!umn.edu!msc.edu!news.gac.edu!poblano!mmiller3
From: w.shrake@genie.geis.com
Newsgroups: comp.binaries.cbm
Subject: Aligning 1541 disks (Part 01/01) Long Text  1541(&1571?)
Followup-To: comp.sys.cbm
Date: 14 Sep 1994 20:46:15 GMT
Organization: Gustavus Adolphus College
Lines: 276
Approved: mmiller3@gac.edu (comp.binaries.cbm)
Message-ID: <357nenINNjm7@news.gac.edu>
Reply-To: w.shrake@genie.geis.com
NNTP-Posting-Host: poblano.gac.edu
Originator: mmiller3@poblano

[This is the 1541 Alignment file mentioned on comp.sys.cbm by Ward last
 week.  Note that I set Reply-To: to Ward's address and Followup-To: to
 comp.sys.cbm, not the normal settings.  Also note that working on your
 equipment is done at your own risk with no warranties whatsoever,
 expressed or implied, etc.-MJM]

Ward Shrake
 
A discussion regarding Commodore 1541 disk drive alignment procedures, with
suggestions.
 
Background information.
 
The best way I've ever seen to consistently and reliably get a 1541 disk drive
aligned perfectly, was caused by copy protection. It is sort of appropo that
copy protection, which usually causes the "head knock" problem that puts drives
out of alignment in the first place, should also be able to solve the problem
it created.
 
An older version of a disk utility program, ("Disector" v3.0, as I remember
it), had copy protection that would not let you load the disk up unless your
disk alignment was perfect. While initially loading itself, it would search and
search, never quitting, until it found what it was looking for, exactly where
it was looking for it. It would stay in an endless loop, searching forever,
never making it to so far as the first screen. This essentially "locked up" the
computer, if the program thought the disk it was on was an illegal copy.
 
This quickly became the most hassle-free, no-worry alignment program I've ever
seen. I have seen and used most of the others; this method beat them all, no
contest, in my opinion.
 
The other programs, the ones made for aligning your drive,  never consistently
worked acceptably well, in my experience. Other technical users apparently feel
the same way about them, as the "General FAQ, v2.1" on Commodores points out.
They would work OK part of the time, or on part of the drives you tried, but
not all, I found. Or they would say you now had a perfectly-aligned drive, but
some difficult copy protection schemes would still not load and run on the
newly tuned-up drive friend. A friend of mine, now deceased, once had a drive
no alignment program could fix. We tried everything we could find. After
aligning it with a given method or program, some programs would load that would
not load before, but others would now no longer work, that used to work before.
All in all, it was very frustrating, and the general feeling was that there has
to be a better, easier, more reliable way to do this.
 
All an alignment program has to do, is to make sure that when the disk drive
says it is precisely at a given track's physical location, that it is really
there, centered on that track.
 
There are other Commodore adjustments, but alignment seems to be, by far, the
most common problem. Disk drive rotational speed can be adjusted, but it
usually is not the problem. In fact, I've seen more than one drive, that when
adjusted to read a program-reported "perfect" 300 rpm rotation speed, they quit
reading disks; requiring speed to be set at a reported 310 rpm, to work again.
The end stop gap can also be adjusted, but I've never seen it be the real
culprit with a non-working disk drive. Your experience may vary, of course, but
I've always found that it is best to concentrate on alignment first, then fool
around with the other adjustments ONLY after alignment is truly corrected, and
only if it still refuses to work properly.
 
Once alignment is corrected, there are methods available to insure that it
stays that way. For instance, you can have the stepper motor's pulley
mechanically pinned to its shaft, instead of merely relying on the factory's
interference fit to hold it. Commodore 1541 drives were made to be self-
aligning, apparently, which would be fine if "head knocking" protection schemes
were not around. Since they are, the pulley should, ideally, not be allowed to
turn on its shaft, which is what causes misalignment problems.
 
How I used to align 1541 disk drives....
 
To precisely align a given 1541 disk drive, I used the old, unbroken copy I had
of Disector (v3.0, I think), and followed these steps.  With power to the drive
off an disconnected,  you first took off the upper and lower halves of the
outer plastic casing of the drive. This exposed the electronics inside. You
then found and loosened (but not removed!) the two stepper motor mounting
screws, which are on the underside of the disk drive's internal mechanisms.
After that, you hooked the power cable back up, and hooked the drive to the
computer like it normally is.
 
Once you've done this, you set the drive up on one side, so that you can
(carefully!) reach into the mechanism, to physically rotate the stepper motor,
which would normally be on the bottom of the drive. You type in the program's
loading instructions on the computer, and you then wait until the screen went
black (copy protection searching for certain info on the diskette). This is
where  the program  "locks up," with the unaligned drive.
 
Once the program is loading, but stuck and unable to find what it wants, you
reach into the mechanism, very slowly and carefully, turning the stepper motor
a slight bit in either direction, and stopping. Tiny adjustments are a lot;
don't overdo it. Be patient; don't go too fast, or move it too much! You watch
the screen carefully, and listen to the drive's sounds.
 
When you have rotated the stepper motor to the proper place, the sounds and the
screen will act a little different, perhaps only slightly so. Wait a second,
not moving the stepper motor at all. When you are right on, alignment-wise, the
program will find what it is looking for, and the program's main menu will
appear.
 
Once the main menu has come onto the screen, you have a perfectly aligned
drive. Then you have to retighten the stepper mounting screws, being very
careful not to accidentally move the motor in the process. Hold the motor
firmly while retightening both screws in small steps, alternating back and
forth between them until they are both tight. The rotational force of the
screws turning, forces the motor to move some, so watch for it.
 
With this method, using a specially-prepared disk, I always got perfect
results; everything would load, every time, from then on. (Assuming that the
disk was formatted with a good drive to begin with; any disks you made
recently, on your badly-aligned drive, may not load after the alignment
procedure.  Transfer the info on these disks, to a second, known-good drive,
before you do this procedure. This is normal, however, no matter what method
you use to align a bad drive.)
 
Here's the problem with this method...
 
This procedure only works with a special disk, one that is no longer available.
With the special disk, alignment is quick, hassle-free, and it always gave
excellent, reliable results the first time around. Without the "perfect" disk,
this procedure is worthless. This is obviously a problem, since the method
relies on a disk that is no longer available to the public. You can't make your
own, because you don't know if the disk drives you are using, are truly perfect
to start with! Disks made by users, on Commodore equipment, never worked; they
just matched your drive's alignment to that of someone else's equipment, which
may be borderline bad to start with.
 
Here's what I suggest to solve this...
 
Your mission, should some hot programmer out there choose to accept it, is to
create a program that will create a "special" disk, and a Commodore-compatible
program to try to read that special disk.
 
Ideally, the Commodore-compatible reading program would be short and simple
enough to fit inside 8k of memory, so it could fit on a cartridge. This would
allow it to work, even if a user's disk drive would not load programs anymore.
It could still be stored on a diskette, too, with a little planning.
 
Theoretically, once you had the specially-formatted diskette, and the program
on cartridge, you would only need a screwdriver to take the drive apart, and a
Commodore microcomputer to run the program on. No other special tools would be
needed, and very little technical knowledge would be required; just some
general safety tips, because you are working around sensitive electronic parts,
with wall current coming into the drive itself, at least on older 1541's.
 
Why should a programmer go to all the trouble?
 
I'm sure there are a lot of people out there who could use this, if some hot
programmer should decide to write it, and make it available to the rest of us.
There are always programmers out there, somewhere, eager to show off their
computer skills, and their creativity. It is one of the things that makes the
computer community so great in the first place. (If people out there can write
IBM-to-Commodore disk file readers, this should be a breeze!)
 
Techies should appreciate it as a great, reliable and cheap way to align
troublesome disk drives, and those people with a C64 in a closet would sure
appreciate their technical buddies getting their dead systems going again!
 
Description of what I have in mind, as to how it should work.
 
You need a Commodore computer (the 64 is most popular), one 1541 disk drive
that needs alignment (or that you want to check), a screwdriver to open the
drive up, a specially-prepared disk used only for alignment purposes, and a
computer program that would run on the Commodore that would look at and analyze
the information that is on the specially-prepared diskette, as the computer
program tries to read it.
 
OK. Here's where it gets cute.
 
The problem with most disk alignment methods, as I see it, is that it relies
totally on technology that the Commodore has available; trying to create a
special disk on a 1541, I just don't see as being realistic, or the best way to
do it. The 1541 has many limitations, compared to some other disk drives which
operate on other computer platforms. Don't get me wrong; I love Commodore
computers, and have for years. But, realistically, the 5.25 inch drives found
in say an IBM machine, are just plain better in many ways than the 1541. They
are made to hold much more information, and to do that, they have to be much
more precise in doing so than the 1541 was ever designed to be.
 
If a person were to do this, I would suggest that they write an IBM program
that would use a high density, 1.2 megabyte capacity, 5.25-inch type of disk
drive to create the special diskettes, which the 1541 would later read.
 
Doing this would allow the creation of very thin tracks on the diskette's
surface, spaced closely together. This would, within the limitations of the
1541's read head, allow the Commodore to "see" precisely where it currently
was, to one side or the other of some "centered" position. The advantage of
thin tracks, widthwise, is that the read head won't see them at all, reliably,
unless you are exactly, perfectly right on top of them. Another advantage to
this, again within the limitations of the 1541's read head (whatever that may
be), is that left or right of center, the head would likely pick up the next
track over, letting you know you were off by a certain amount automatically.
 
I hope I'm making myself clear, in my explanation of this. If I am not, Email
me with your questions, and I'll try to answer them better, and/or update this
file, to entice someone else to work on this. I really would like to see it
done. (Current Email address, as of Sep 94: wardshrake@aol.com on the Internet,
or just WardShrake on AOL. Will soon have a Compuserve Email address, too: I'll
be user 75207,1005 there, or 75207.1005@compuserve.com on the Internet.)
 
Anyway, let's continue. With the IBM creating a specially-made disk just for
this one purpose, you would not even have to worry about following any standard
formatting procedures. No user-stored data would ever be written to the
diskette, so standard sectoring could be safely ignored. You could create any
signal or sectoring scheme you like, as long as the IBM could create it, and
the Commodore could read it; and you'd be writing both programs, anyway, making
this easier to insure, right?
 
I can hear some die-hard Commodore users saying, "I hate IBM's" or "I don't
even have an IBM" or some such. Fine. Not a problem. If all the IBM-compatible
program did was to create a special floppy disk, once, then quit, you would not
even need to OWN an IBM, you'd just need to be able to USE one for a few
minutes.
 
Even if you don't have access to one at work, and don't know of anyone who has
one to lend you, I will stick with this suggestion, because I know that some
businesses that make photocopies often also rent IBM's and Mac's on an hourly
basis, for very little money. My local Kinko's copy center rents them both at
$10.00 an hour. You would only need it for a few minutes or so.
 
The diskette-creation program would only need a few minutes to run, to make up
a special disk, so you'd only be paying for a good quality, blank high density
floppy, and ten or fifteen minutes of rental time, tops. The copy center person
may even be able to start up the floppy-based IBM program for you, if you don't
know how to do it yourself. That should come to $5.00 or less, even if you
don't own or normally have access to an IBM compatible computer! You can't beat
that, for a utility to align equipment!
 
OK. In overview, you'd need to use an IBM-compatible computer, just long enough
to load an IBM-compatible program which would create one special, 5.25"
diskette, perhaps on a high density floppy. You would then open up your
Commodore drive's case, and start up a special program on your Commodore 64, to
read the created diskette. (Again, an 8k Commodore program would fit very
easily on a cartridge, for easiest loading and running.)
 
While the computer and drive were running, you would (very carefully, and
observing safety precautions) loosen the stepper motor's screws, and slowly
turn the motor clockwise and counter-clockwise, until the Commodore program's
screen info told you that you were exactly where you should be, right over the
proper track. Not to the left or right of it, but in perfect alignment.
 
Because the Commodore disk-reading program would be "on" constantly, and
reporting any small changes to you via information on your screen, you would
only have to take a few minutes of fiddling, doing a simple, non-technical
turning of the stepper motor, to get the drive aligned. The two computer
programs that would make up this package would be doing most of the work.
 
I imagine a drive could be perfectly aligned, and back in running order, in
fifteen minutes or less. Five, if you paid attention to the process, and had
some practice before. Remember, this is based on an alignment procedure I
really used to do, using a heavily-protected diskette, so I am extrapolating
from my personal experiences, even though I'm talking about a theory here.
 
I don't see where there would be any easier, simpler method of doing a disk
alignment. The user wouldn't even have to know a thing about tracks and
sectors; they would just loosen two screws, following some instructions, and
turn the motor. What could be any easier?
 
The program could, if it was really creative and well-done, tell them to rotate
the motor clockwise or counter-clockwise (as they face it), to dial the motor
precisely in. Tracks to either side of an arbitrary (track 18?) center position
would say to go one way, tracks on the other would say the reverse. When you
turn it too far one way, it would reverse its instructions to you; you would
know you were very close then. When you were "right on," the program would tell
you so. You'd lock the screws down, carefully, and as long as you hadn't
jiggled the motor when you tightened it back down, you would be all done!
 
How much easier could it be, right? (On the final user, that is!)
 
If anyone is interested in doing this, or goes out and does it, please let me
know via Email. I'd like to hear about it. Again, it would be something
possible, useful, and a really neat trick. I know there are people out there
that program on both the IBM and the Commodore; the various cross-reading
programs attest to that, well enough!
 
Ward Shrake
Covina, California