This file describes the alignment
problems common to 1541's.  The align-
ment procedure described should NOT be
attempted by someone that does not have
either the proper fix-it skills or
attitude.
The early 1541's (white cased) also 
have a heat-related alignment problem.
If the drive is on for a few hours,
heat buildup inside affects the thin
metal drive band that moves the r/w
head.  If you have problems saving or
reading a file on a disk that was
written to during a recent session, 
then this is probably the cause.
Either shut your 1541 off when not 
using it, or place a very low CFM fan
to blow air through the drive (you
should filter the air going through the
drive, but if air enters from the top,
and it is moving slow, dust will
settle on the board before getting in
the drive machanism.
The other alignment problem comes from
extensive NEWing of disks, or from the
errors generated by copy-protected
software.  The alignment slowly changes
due to wear.
The following process describes how
to align your 1541 using the TEST/
DEMO disk shipped with the drive:
Enter the following prg & save it-
100 OPEN1,8,15:OPEN4,8,4,"#"
110 FT=1:FT$=STR$(1):LT=35
120 LT$=STR$(LT)
130 PRINT#1,"U1:";4;0;LT;0
140 T$=LT$:GOSUB500
150 PRINT#1,"U1:";4;0;FT;0
160 T$=FT$:GOSUB500
170 LT=LT-1:IFLT>0THEN120
180 CLOSE4:CLOSE1:END
500 PRINT"READING TRACK:";T$
510 INPUT#1,EN,EM$,ET,ES
520 PRINTTAB(12)EN;EM$;ET;ES
530 IFEN<2 THEN RETURN
540 PRINT:PRINT"DRIVE HAS FAILED"
550 GOTO 180
(The above routine has been extracted
from a 1541 test by Steven Niers)
Once you have the above prg saved on
a disk and ready to run in memory,
unplug the 41, remove the cover (four
screws on bottom), and remove the
metal shield covering the circuit
board. Next, remove the circuit board
leaving all wires and cables attached
(be careful of the small cable from
the read/write heads). Set the board
over to the LEFT side of the drive,
placing cardboard between it and the
metal frame of the drive - MAKE SURE
NO part of the circuit board touches
any metal parts of the drive!
Look at the drive itself - There are
two metal pulleys, with a thin metal
drive band around them. This is the
drive mechanism for the read/write
heads. The rear pulley is the one
drvien by the motor. You'll see two
fat metal 'pegs' or bumps on top of
it with a metal 'stop' protruding
from a post behind the pulley.
WITHOUT moving the stop, loosen the
screw on the stop until you think the
stop can be moved WITH A LITTLE FORCE
(Try moving the stop to the left very
slightly by tapping on a large flat-
bladed screwdriver or so pressed
against the stop)  Now plug in the 41
and turn on power (make sure the 
circuit board is isolated from any
metal parts!!!!). 
(1541 align cont.)   Put in the 1541
TEST/DEMO disk shipped with the drive
and run the program you just
entered. It reads track 35, then 1,
then 34, then 1, then 33, etc....
If alignment is OK, this will go thru
all 35 tracks without an error.
Notice that when going to track 1
sometimes the drive 'backs-up' and
'flicks' the drive pulley until it
hits the stop.  On a properly
aligned drive, there is only a 16th
of an inch, give or take, of space
between the position of the pulley
bump and the metal stop to 
successfully read track 1.
If the program fails before completing
move the stop VERY slightly to the
left by tapping it again.  Run the
program again.  Keep doing this until
the program runs error free.  A
properly aligned disk is also a little
quieter during disk-errors or NEWing
a disk.  By moving the stop a little
one way or the other, you'll get the
feel of where it should be.  ONLY
move it as little as possible each
time!
Do not use a copy-protected disk for
this alignment procedure!  WordPro
especially will screw you up since it
is copy-protected by corrupting track
#1!  The 1541 test/demo disk is the
closest you'll find to a standard.
When alignment is OK, DON'T try to
tighten the screw on the stop! It'll
only change the position of the stop-
that's why I said to loosen it ONLY
until the stop can be moved with
force. Now apply some Elmer's glue or
similar onto the screw and edges of
the stop to keep it from moving.
Check alignment again. Unplug the
drive, put the circuit bd. back in
place, turn on the drive, check align
ment again, and so forth until you
have the drive all back together.
If you had trouble reading disks like
WordPro, then before you put it back
together, try loading one of them. If
they don't load at least 80% of the
time, move the stop slightly either
way and try again. When it works, try
the alignment program again, etc.
Note: do NOT use epoxy to hold the
stop in position. You may need to do
the procedure more than once.
