Dysan 224 User manual

5440 Patrick Henry Drive
Santa Clara, California 95050
[phone]
DYSAN 224 ALIGNMENT INSTRUCTIONS
The Dysan 224 Alignment Diskette is used for alignment
operations on 5.25" flexible disc drive units. The media
itself is
physically compatible with the Dysan 104/1 Disk-
ette (described in Dysan Engineering Specification
810150). The Dysan 224 Diskette has been recorded with
special purpose data in order to accomplish alignment
operations associated with most 5.25" flexible disc drives.
Note: Care
should be exercised not to record on
the diskette. To do so will destroy its use-
fulness
as an alignment tool. The write
enable notch has been deleted from the
diskette jacket to minimize the possibility
of inadvertent recording on the diskette.
This protective feature, however, is only
functional on those drives that incorporate
a write protect feature.
A
description of the alignment operations that can be per-
formed
with the Dysan 224 Alignment Diskette is as
follows:
Recommended Operation
Track 00 Detector
Adjustment
Index/Sector Photo
Transducer Alignment
Read/Write Head Radial
Alignment
Read/Write Head Load
Pad
Adjustment
Track Number
00
01
16
34

I. Read/Write Head Radial Alignment
A. Insert Dysan 224.
Note: Before using the Dysan
Alignment Diskette,
it
should be allowed to acclimate to the en-
vironment in which you intend to use it for
as long as it was removed from that environ-
ment or up to 24 hours, whichever occurs
first.
B. Step the Head Carriage to track 16.
C. Sync an oscilloscope on "Index". Set time base
to 20 msec/division. This should display one
revolution.
D. Connect two probes and set the vertical deflec-
tion in such a fashion as to display the read sig-
nal at the output of the differential amplifier.
Ground the probes to the drive Printed Circuit
Board (PCB). Set the inputs to AC, Add and in-
vert one channel.
E. The lobes displayed should be within 70% am-
plitude of each other. (See Figure 1) If the lobes
do not fall within this specification, continue to
Step F.
F.
Loosen the screws which will allow radial ad-
justment of the Head Carriage. (It is recom-
mended that the stepper motor or servo system
be
electrically detented while making this
adjustment.)
G. Adjust the Head Carriage in or out as necessary
to get the lobes to be equal in amplitude.

EQUAL AMPLITUDE
(ON TRACK 16)
LEFT 80% OF
RIGHT
(-1 MIL OFF TRACK,
TOWARD 15)
LEFT 60% OF RIGHT
(-2 MIL OFF TRACK,
TOWARD 15)
-I
LEF I" 40% OF RIGHT
(-3 MIL OFF TRACK,
TOWARD 15)
RIGHT 80% OF LEFT
(+1 MIL OFF TRACK,
TOWARD 17)
RIGHT 60% OF LEFT
(+2
MIL OFF TRACK,
TOWARD 17)
RIGHT 40% OF LEFT
(+3
MIL OFF TRACK,
TOWARD 1·7)
Figure 1

H. Tighten the screws which were loosened in
Step
F.
I. Check the adjustment by stepping off track and
returning. Check in both directions.
J. Whenever Radial Head Alignment has been ad-
justed,
the Track 00 Detector Adjustment and
Track 00 Stop must be checked.
II. Track 00 Detector Adjustment
A. Insert Dysan 224.
B. Step Carriage to track 00.
C. Connect oscilloscope in such a fashion as to
display the read signal at the output of the dif-
ferential amplifier. Add differentially and sync
on "Index". Set time base to 20 msec/division.
D. The signal displayed should be a full revolution
all "1 's" data pattern. This data is written only on
track 00 in this area of the diskette, thus by
observing this signal track 00 may be easily
identified.
E. Referring to the drive manufacturer's instruc-
tions, and observing the track 00 detection
signal adjust the Track 00 Detector.

111. Index/Sector Photo Transducer Alignment
A. Insert Dysan 224.
B. Step Carriage to track 01.
C. With oscilloscope triggered on the leading edge
of "Index", set the time base to 50 usec/division.
D. Connect probes and set vertical deflection in
such a fashion
as to display the read signal at
the output of the differential amplifier. Ground
probes to the PCB. Set the inputs to AC, Add
and invert one channel.
E. Observe the timing between the start of the
sweep and the first data pulse. This time should
be 200 usec +100 usec. If the timing is not within
this tolerance, continue to Step F.
F. Observing the timing, adjust the Transducer in
accordance with the manufacturer's instruc-
tions until a 200 usec + 50 usec time incre-
ment is obtained.
IV. Read/Write Head Load Pad Adjustment
Note:
This procedure only applies to those flex-
ible
disc drives that have adjustable Head
Load Pads.
A. Insert Dysan 224.
B. Step Carriage to track 34.

C. Connect an oscilloscope in such a fashion as to
display the read signal at the output of the differ-
ential amplifier. Add differentially, and sync on
"Index". Set the time base to 20 msec/division.
D. While observing read signal on the oscillo-
scope, rotate the Load Button counterclockwise
in small increments (10°) until a maximum am-
plitude is obtained.

DYS079-3 ( 11 '79)