Originally posted by: mrr@rayssd.UUCP
Message-ID: <535@rayssd.UUCP>
Date: Thu, 11-Oct-84 12:49:50 EDT
Article-I.D.: rayssd.535
Posted: Thu Oct 11 12:49:50 1984
Date-Received: Sat, 13-Oct-84 06:00:48 EDT
Organization: Raytheon Co., Portsmouth RI
Lines: 76
Before I begin...I recently submitted a review of the MAE assembler/devel-
opment system, but I think I screwed up on distribution. If you didn't see
it and are interested, let me know.
Last night I realigned my secondary 1541 disk drive (sigh of relief) with
the help of a software package I recently purchased from C.S.M. software
of Indiana. Anyone who has owned a 1541 for more than a year (sometimes less)
has probably encountered alignment problems by now, even if it is not
recognized as such. The problem is especially noticable when loading
programs - much clanging (head reset) and flashing of the busy light.
Well, my older drive got so bad that it couldn't read disks created by the
newer one (and vice versa) so I decided to do it myself. The alignment kit
comes with two diskettes - a program diskette and a calibration disk.
Operating instructions come in a very thin (but complete) 8 x 11 stapled
booklet. My first attempt to load the software resulted in a dismal failure.
after about a minute, my screen went blank and the disk continued to spin.
After trying several resets, I called the company (Friday afternoon) and
talked to someone technically competent who stated that the software protection
scheme was preventing the load, probably because my drive was out of alignment -
quite a catch-22! He asked if I had access to another 1541. I explained that
I did not and that the problem was on my good 1541 which had no problems
with other commercial software. That established, he agreed to mail a new
set of diskettes. They arrived a week later with a return authorization for
the original pair. I guess that establishes a certain amount of respectability
though the additional wait was aggravating.
The alignment procedure starts out with the dismantling of your drive,
removing the chassis from the plastic housing, removing the metal shield and
(moan!) removing the printed circuit board from the chassis. The alignment
must be done with power applied to the drive in its nude condition with the
pc board floating (I protected its bottom with a taped-on double sheet of
paper). The first operation consists of a speed adjustment which is quite
easy. You adjust a potentiometer while a speed percentage is displayed on
the monitor - 100.00 % is the goal, though allowable tolerances are given.
You next execute the 'Bump and Alignment' procedure which I found to be
quite painful. According to the instructions, the busy light (red indicator)
will stay on continuously when you have a good alignment. I never did
reach that condition, so I settled for the least amount of flicker I could
achieve. Also, the stepper motor cam, after a 'bump', should be pretty
close to .010 inch from the cam stop.
The 'Check Alignment' test actually steps through a series of tracks and
sectors, using the calibration diskette, and timing the operation. After
each cycle, a "T.N." number is reported which should be close to 100.
Again, tolerances are given. My final result was 100.05 which I assume is
pretty good.
By repeating these two procedures, it appears that you can achieve a good
alignment. I created a new calibration disk (on both drives) and tested
them on my newly aligned drive with very consistent good results. I also
made a backup copy of a large assembler application on the secondary disk,
then ran the assembly on the primary using the backup with no sign of a
stutter - impossible before I started.
Also included in the instructions is a method for pinning the cam to its
shaft (for the very brave) since it is the cam that apparently slips,
causing misalignment. I may try this a few alignments down the road, but
not now.
This package does not have a polished, "professional" appearance. No fancy
labels and documentation could be proof-read and enhanced, but I am well
pleased with the results. If you have common sense, fair mechanical ability
and some patience, this package will save you a trip to the repair shop and
at 39.95, will probably pay for itself the first time you use it.
I am very interested in others opinions and experiences with commercially
available software and hardware for the Commodore 64. It's hard to get
past the hype (and sometimes understatement) in advertising to determine
the usefulness of a product. If you've purchased a product that you
consider noteworthy (good or bad), please share it with all of us.
Mark Rinfret
SofTech, Inc.