Shugart SA800 User manual

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© Copyright 1977 Shugart Associates

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TABLE OF CONTENTS
Section
Maintenance Features
Page
2
3
4
5
6
7
8
9
Diagnostic Techniques
Preventive Maintenance.
Removals Adjustments .
Physical
Locations . .
SA809 Exerciser Connections
SA800/801 PCB Component Locations
SA800/801 Logic Manual. . .
SA800/801 Schematic Diagrams
3
5
7
17
21
22
23
31

1.0 MAINTENANCE FEATURES
1.1 Alignment Diskette
The SA120 Alignment Diskette is used for align-
ment of the SA800/80l. The following adjust-
ments can be made using the SA120.
1. R/W Head radial alignment using track 38.
2. R/W Head azimuth alignment using track 76.
3. Index Photo-Detector Adjustment using tracks
01 and 76.
4. Track 00
is recorded with standard IBM 3740
format.
5.
TK 75 has If + 2f signal for load pad adjustment.
Caution should be exercised in using the SA120
Alignment Diskette. Tracks
00, 01,36,37,38,39,
40, 75, and 76 should not be written on. To do so
will destroy pre-recorded tracks.
1.2 SA809 Exerciser
The SA809 Exerciser is built on a PCB whose
dimensions are
8" x 8". The Exerciser PCB can be
used in astand alone mode or it can be built into
atest station or used in atester for field service.
The Exerciser is designed
to enable the user to
make all adjustments and check outs required on
the
SA800/80l drives, when used with the SA120
alignment diskette.
The exerciser has no intelligent data handling
capabilities
but can write both If and 2f frequen-
cies. The exerciser can enable read in the drive
to
allow checking of read back signals.
Refer
to Section 6for illustration.
1.3 Special Tools
The following special tools are available for
performing maintenance on the SA800/80
1.
Description
AlignmentDiskette
Cartridge Guide Adj. Tool
Head Penetration Gauge
Load Bail Gauge
Exerciser
Spanner Wrench
Part Number
SA120-1
50377-1
50380-0
50391-0
50619-0
50752-0

3
2.0 DIAGNOSTIC TECHNIQUES
2.1 Introduction
Incorrect operating procedures, faulty program-
ming, damaged diskettes, and
"soft errors" created
by airborne contaminants, random electrical noise,
and other external causes can produce errors
falsely
attributed to drive failure or misadjustment.
Unless visual inspection
of the drive discloses an
obvious misalignment or broken part, attempt to
repeat the fault with the original diskette, then
attempt to duplicate fault on second diskette.
2.2 "Soft Error" Detection and Correction
Soft errors are usually caused by:
1. Airborne contaminants that pass between the
read/write
head and the disk. Usually these
contaminants can be removed
by the cartridge
self-cleaning wiper.
2. Random electrical noise
that usually lasts for a
few
f.1 sec.
3. Small defects in the written data
and/or track
not detected during the write operation that
may cause asoft error during aread.
4. Worn or defective load pad.
The following procedures are recommended
to
recover from the above mentioned soft errors:
1. Reread the track ten (10) times or until such
time
as the data is recovered.
2.
If data is not recovered after using step 1, access
the head
to the adjacent track in the same
direction previously moved,
then return to the
desired track.
3. Repeat step
1.
4. If data is not recovered, the error is not
recoverable.
2.3 Write Error
If an error occurs during awrite operation, it will
be detected on the next revolution
by doing aread
operation, commonly called a"write check." To
correct the error, another write and write check
operation must be done.
If the write operation is
not successful after ten (10) attempts have been
made, aread operation should be
attempted on
another track
to determine if the media or the
drive
is failing. If the error still persists the diskette

2.6 Test Points--800/801
should be replaced and the above procedure
repeated. If the failure still exists, consider the
drive defective. If the failure disappears, consider
the original diskette defective and discard it.
2.4 Read Error
Most errors that occur will be "soft" errors.
In these cases, performing an error recovery
procedure will recover the data.
2.5 Seek Error
1. Stepper malfunction.
2. Improper carriage torque.
To recover from aseek error recalibrate to track
00 and perform another seek to the original track.
TP 1
2
3
4
5
6
7
10
11
12
16
21
24
25
26
27
Read
Data Signal
Read Data Signal
Read Data (Differentiated)
Read Data (Differentiated)
Signal
Ground
Signal Ground
Signal Ground
- Index
+ Head Load
- Index and 801 Sector Pulses
+Read Data
-Data Separator Time +1
-
Data Separator Time +2
+Write Protect
+ Detect Track 00.
+ Gated Step Pulses
2.7Test Point Locations
1 II
•
CD
•J5 10
•
CD
11
0
7J2
P2
0
25
26 0
012 A
20
P1
J1
CD
~
J6CD
27
•
49 0
21
10
0 0
16
0
0
24 2 1
0010
~
0
6J3
ii
04350
000
P3
4

3.0 PREVENTIVE MAINTENANCE
3.1 Introduction
The prime objective of any preventive maintenance
activity
is to provide maximum machine avail-
ability to the user. Every preventive maintenance
operation should assist in realizing this objective.
Unless apreventive
maintenance operation cuts
machine downtime, it
is unnecessary.
Visual inspection
is the first step in every sched-
uled maintenance operation. Always
look for
corrosion, dirt, wear, binds,
and loose connections.
Noticing these items during
PM may save down-
time later.
Remember, do
not do more than recommended
preventive maintenance on
equipment that is
operating sa tisfactorily.
3.2 Preventive Maintenance Procedures
Details of preventive maintenance operations are
listed in Figure
1. During normal preventive
maintenance,
perform only those operations listed
on the chart for
that preventive maintenance
period. Details on adjustments
and service checks
can be found
in the maintenance manuaL Observe
all safety procedures.
3.3 Cleanliness
Cleanliness cannot be overemphasized in maintain-
ing the SA800/80
1. Do not lubricate the SA800/
801; oil will allow dust and dirt to accumulate.
The read/write
head should be cleaned only when
signs
of oxide build up are present.
FREQ
UNIT MONTHS CLEAN OBSERVE
Read/Write Head 12 Clean Read/Write Head Oxide build up
ONLY
IF NECESSARY
R/W Head
Load
12* Replace
Button
Stepper Motor and
12
Clean off all oil, dust, Inspect for nicks and burrs
Lead Screw 12 and dirt
Belt
12
Frayed or weakened areas
Base 12 Clean base Inspect for loose screws,
connectors, and switches
Read/Write Head 12 Check for
proper alignment
*Assumes normal usage Figure 1
PM Procedures
5

7
4.0 REMOVALS, ADJUSTMENTS
For parts location, see Section 5.
4.1 Motor Drive
4.1.1 Drive
Motor Assembly: Removal and
Installation
a. Extract 3contacts to disconnect motor from
AC connector.
b. Loosen
two screws holding capacitor clamp to
the base. Remove rubber
boot and disconnect
motor leads from capactior.
c. Remove connectors from PCB and remove PCB.
d. Remove belt from drive pulley.
e. Remove 4screws holding the motor to the base
casting and remove
motor.
f. Reverse the procedure for installation.
Note: Insure ground lead
is installed between
capacitor clamp and base.
4.1.2 Motor Drive Pulley
a. Loosen set screw and remove pulley.
b. Reverse procedure for installation.
Note: When installing anew pulley, the drive
pulley
must be aligned with the spindle
pulley so
that the belt tracks correctly.
4.2 Side Cover: Removal
a. Retract screw from upper casting wall suffi-
ciently
to allow the side cover to be rocked out.
b.
Lift cover off screw in lower casting wall.
4.3 Cartridge Guide Access
a. Remove side cover (Section 4.2).
b. Position
head to approximate center of head
load bail
(to prevent load arm damage).
c. Loosen 2screws holding cartridge gUide to door
latch plate.
d. Swing cartridge guide
out.
e. When the guide is swung in, it must be adjusted
as per Section 4.9.2.

4.4 Sector/lndex LED Assembly: Removal and
Installation
a. Remove side cover (Section 4.2).
b. Disconnect the wires to the LED terminals
(solder joints).
c. Remove the screw holding the LED assembly to
the cartridge guide.
d. Reverse the procedure for installation.
e. Check index timing and readjust
if necessary.
4.5 Write Protect Detector: Removal and
Installation
a. Remove connectors from PCB and remove PCB.
b.
Extract wires from P2 connector, pins L3, L4,
R5 (E), and R8 (S).
c. Remove cable clamps.
d. Remove side cover (Section 4.2).
e. Remove screw holding the detector bracket and
remove assembly.
f. Reverse procedure for reinstalling. Connect the
wires
to P2 by the folloWing: Red to '3' (L3),
Grey
to '4' (LA), Black to 'E' (R5) and White
to
'J' (R8).
4.5.1 Write Protect Detector Adjustment
a. Insert SA101 diskette into drive. Write protect
hole must be open.
b. Set oscilloscope to AUTO sweep, 2V/div. and
monitor TP25.
c. Loosen screw
on detector assembly and adjust
until maximum amplitude
is achieved. Tighten
screw.
4.6 Head Load Actuator
4.6.1 Head Load Actuator: Removal and
Installation
a. Remove side cover (Section 4.2).
b. Disconnect the wires to the actuator terminals
(solder joints).
c. Swing
out the cartridge to guide assembly
(Section 4.3).
8
d. Remove screw holding the actuator to the
cartridge guide.
CAUTION: Restrain the head load arm to pre-
vent its impact with the head.
e. Reverse the procedure for installation.
4.6.2 Head Load Actuator Adjustment
a. Remove side cover.
b. Energize Head Load Coil.
c. Place Head Load Actuator adjustment tool,
PIN 50391, on platen.
d. Adjust down stop so that the top of Head Load
Bail
is flush with top of tool within ± .005" at
track 76. Reference Figure
3.
e. Step carriage to track 38.
f. De-energize Head Load Coil.
g. Place adjustment tool onto R/W Head and place
load
button in cup of tool.
h. Adjust up stop on actuator
so that bail just
touches Head Load Arm or has .005" clearance
or lifts Load Arm .005". Reference Figure
2.
1. Energize Head Load Coil and step carriage
between track 00 and 76. Insure
that there is a
clearance
of aminimum of .010" between Head
Load Bail and Head Load Arm.
j. Replace side cover.
UP STOP
ADJUSTMENT
ISCREW
FLUSH WITHIN ±.005
~
UP STOP
FIGURE 2 HEAD LOAD ACTUATOR UPSTOP
ADJUSTMENT
ADJUSTMENT
======='=i~--- SCR EW
DOWN STOP
BAIL TOOL
(FLUSH)
WITHIN ±.005
~~~ '-C.-~~-l:::L.1
BASE CASTI NG PLATEN ___
FIGURE 3 HEAD LOAD ACTUATOR DOWN STOP
ADJUSTMENT

4.6.3 Head load Actuator Timing
a. Insert Alignment Diskette (SA120).
b.
Step carriage to track 00.
c. Sync oscilloscope on TP 11 (+ Head Load). Set
time base to 10MSEC/division.
d. Connect one
probe to TPI and the other to
TP2. Ground probes to the PCB. Set the
inputs to add and invert one inpu t
e. Energize the Head Load solonoid
and observe
the read signal on the oscilloscope. The signal
must be
at 50% of full amplitude by 35Msec.
Reference Figure
4.
f. If this is not met, continue on with the
procedure.
g. Check adjustments outlined in paragraph
4.6.2.
h.
If item 'g' is ok, adjust down stop screw
(Figure
6) clockwise until timing is met.
Note: Not to exceed ~ turn.
FIGURE 4 HEAD LOAD ACTUATOR TIMING
4.7 Index/Sector Photo Transistor Assembly
4.7.1 Index/Sector Photo Transistor Assembly:
Removal and Installation
a. Disconnect P2 connector from PCB.
b. Remove wires from
Door Closed switch and
extract wires from P2 connector pin 9 (L9)
Black, H (R7) Brown, 6 (L6) Red and B (R2)
Orange.
c. Remove cable clamp holding wires
from
detector.
9
d. Remove screw holding detector to the base
plate and remove assembly.
e.
To install reverse procedure.
4.7.2 Index/Sector Photo Transistor
Potentiometer Adjustment
a. Insert Alignment Diskette (SAI20).
b. Using oscilloscope monitor TP-12 (- Index),
sync internal negative,
DC coupled, set vertical
scale
to 2 V/cm.
c. Adjust the potentiometer on the Sector/Index
Photo transistor to obtain apulse of 1.7 msec.
±.5 msec. duration.
d. Continue
adjustment in Section 4.7.3.
4.7.3 Index/Sector Adjustment
a. Insert Alignment Diskette (SA120).
b.
Step carriage to track 01.
c. Sync oscilloscope, external negative, on TP 12
(- Index). Set time base to 50 psec/division.
d. Connect one probe to TP 1 and the other to
TP 2. Ground probes to the PCB. Set the inputs
to AC, Add and invert one channel. Set vertical
deflection
to 500 MV /division.
e. Observe the timing between the start of the
sweep and
the first data pUlse. This should be
200 ±100 jJ.sec. If the timing is not within
tolerence,
continue on with the adjustment.
Reference Figure
5.
FIGURE 5 INDEX TIMING

f. Loosen the holding screw in the Index Trans-
ducer until the transducer
is just able to be
moved.
g. Observing the timing, adjust the transducer
until the timing
is 200 ±100 f.1sec. Insure that
the transducer assembly is against the registra-
tion surface on the base casting.
h. Tighten the holding screw.
i. Recheck the timing.
j. Seek
to track 76 and reverify that the timing is
200 ±100 f.1sec.
4.8 Spindle Assembly
a. Remove side cover (Section 4.2).
b. Swing
out cartridge guide (Section 4.3).
c. Remove the nut and washer or 2spring washers
holding the spindle pulley. On late level drives,
Spanner Wrench 50752 may be used to hold
spindle.
CAUTION: The pre-loaded rear bearing may fly
out when spindle pulley is removed.
d. Withdraw spindle hub from opposite side
of
baseplate.
e. Reverse the procedure for installation.
f. Tighten nut to 20 in./lbs. If spring washers are
used, insure they are compressed. Add adrop
of LOCTITE® #290 to threads.
4.8.1 Clamp Hub Removal
a. Remove hub clamp plate. Reference Figure 6.
b. Remove clamp hub and spring.
c. To install, reverse the procedure. No adjustment
necessary.
4.9.1 Cartridge Guide Removal
a. Perform steps 4.3 through 4.6.1.
b. Remove C-clip form pivot shaft.
Reference Figure7.
c. Remove pivot shaft.
d. Tilt the cartridge gUide slightly, and remove it
from the upper pivot.
e. To install the cartridge guide, reverse the
procedure.
PIVOT SHAFT
\ /REMOVE C CLIP
FIGURE 7 CARTRIDGE GUIDE REMOVAL
4.9.2 Cartridge Guide Adjustment
a. Insert the shoulder screw (tool PIN 50377-1)
through the adjustment hole in the cartridge
gUide and screw completely into the base cast-
ing (hand tight). Reference Figure
6.
b. Move the handle into the latched position and
hold it lightly against the latch.
c. Tighten two screws holding the cartridge guide
to the latch plate.
CARTRIDGE
GUIDE
ADJ. TOOL
HUB CLAMP PLATE
J
o
d. Remove the tool and check to determine the
flange on the clamp hub clears the cartridge
guide when the spindle
is rotating. If the clamp
hub rubs on the cartridge guide, repeat the
adjustment procedure.
e. Check index alignment per Section 4.7.3.
f. Insert diskette, close and open door, then check
for proper operation.
MOUNTING
SCREW
ADJUSTING
SCREW
FIGURE 6 CARTRIDGE GUIDE ADJUSTMENT
10
4.10 Front Plate Assembly: Removal
a. Remove side cover (Section 3.4.2).
b. Swing out the cartridge guide assembly (Section
4.3).

c. Remove 4screws holding the front plate
assembly to the base casting.
d. To install, reverse the procedure.
e. Check Index adjustment Section 4.7.3.
4.11 Head Amplitude Check
These checks are only valid when writing and
reading back
as described below. If this amplitude
is below the minimum specified, the load pad
should be replaced and the head should be cleaned
if necessary before re-writing and re-checking.
Insure the diskette used for this check
is not
"worn" or otherwise shows evidence of damage on
either the load pad or head side.
a. Install good media.
b. Select the drive and step to TK 76.
c. Sync the oscilloscope on
TP-I2 (- Index) con-
nect one probe on TP-2 and one
on TP-I, on
the drive PCB.
Ground the probes to the PCB
add and invert one input. Set volts per division
to 50mv and time base to 20 Msec. per diVision.
d. Write the entire track with 2F signal (all one's).
e. The average minimum read back amplitude,
peak
to peak, should be 110 millivolts.
If the outpu t is below minimum and anew load
pad and different media
is tried and the output is
still low, it will be necessary to install anew head
and carriage assembly.
4.11.1 Stepper/Carriage Assembly; Removal and
Installation
a. Remove cable clamp holding R!W head cable
on PCB side of drive.
b. Remove side cover (Section4.2).
c. Extract stepper cable contacts from P2 connec-
tor. Black 10 (L10),
Red 2(L2), Brown 5 (1.,5),
and Orange 8(8).
Note: This step is only necessary if the stepper
motor is to be replaced.
d. Loosen (2) screws and swing clamp down to
allow withdrawl of motor.
CAUTION: DO NOT LOOSEN
THREE
SCREWS COATED WITH GLYPTOL.
11
e. Remove the grommet on the cable that is
inserted into aslot on the Track 00 Detector
bracket.
f. Turn stepper shaft until the carriage runs
off
the end of the lead screw.
g. To install stepper!carriage assembly, reverse
procedure. Note steps
"h" and "i".
h. If installing anew carriage, set the pre-load nut
in the #2 notch. Reference Figure 8.
i. When threading lead screw into carriage
assembly, press the pre-load
nut slightly against
spring in order
to start thread. After threading,
insure there
is agap between pre-load nut and
rear
of carriage.
-SPRING
rO··-
I'.0 PRE-LOAD
,--
I. ;:"}. NUT
I C>
If '~~NOTCH #4
O~i ~~:-
, \1-- NOTCH #3
o NOTCH #2
NOTCH #1
FIGURE 8 CARRIAGE ASSEMBLY
4.11.2 Carriage Assembly Readjustment After
Replacement
a. Loosen Track 00 stop collar and manually move
the carriage towards the stepper
by rotating the
lead screw until the carriage load arm tab
is near
the edge
of the load bail. Tighten the collar set
screw.
b. Position the Track
00 flag approximately in
the center
of its slot and tighten the screw.
Move the carriage towards the spindle by rotat-
ing the lead screw until the flag
is clear of the
detector.
c. Insert the
SAI20 alignment diskette and load
the head. Set the scope
as explained in Section
4.11.3 steps cand
d.
d. Step the carriage towards track 00 until the
track 00 signal is
detected on the interface pin
42.

e. Loosen the 2stepper motor mounting screws
slightly and slowly rotate the stepper
motor
case until aread data signal off of track 00
appears. Continue
rotation until maximum
amplitude
is obtained. This is only arough
adjustment.
CAUTION: DO NOT LOOSEN THREE
SCREWS COATED WITH GLYPTOL.
f. Step the carriage to TK 38 and proceed with
head radial adjustments. Refer to Section 4.11.3.
g. Adjust Track 00 stop (Section 4.11.7).
h. Adjust Track
00 flag (Section 4.11.8).
i. Adjust index (Section 4.7.3).
j. Adjust Azimuth (Section
4.11.9 ).
4.11.3 Head Radial Alignment
Note: Head radial alignment should be checked
prior to adjusting index/sector, Track
00
flag or carriage stop.
a. Load alignment diskette (SA120).
Note: Alignment diskette should be at room
conditions for at least twenty minutes
before alignment.)
b. Step the carriage
to track 38.
c. Sync the oscilloscope, external negative,
on
TP 12 (- CE Index). Set the time base to 20
Msec per division. This will display over one
revolution.
d. Connect one probe
to TP 1and the other to
TP
2. Ground the probes on the PCB. Set the
inputs
to AC, Add and invert one channel. Set
the vertical deflection to 100
MV /dev.
e. The two lobes must be within 70% amplitude
of each other. If the lobes do not fall within the
specification, continue
on with the procedure.
Reference Figure
9.
f. Loosen the two mounting screws which hold
the
motor clamp to the mounting plate.
CAUTION: DO NOT LOOSEN THREE
SCREWS COATED WITH GLYPTOL.
g. Rotate the stepper motor to radially move the
head in or
out. If the left lobe is less than 70%
of the right, turn the stepper motor counter-
clockwise
as viewed from the rear. If the right
lobe
is less than 70% of the left lobe, turn the
stepper
motor clockwise as viewed from the
rear.
12
FIGURE 9 HEAD RADIAL ALIGNMENT
h. When the lobes are of equal amplitude, tighten
the
motor clamp mounting screws. Reference
Figure
9.
i. Check the adjustment by stepping off track and
returning. Check in
both directions and readjust
as required.
j. Whenever the Head Radial Alignmenthas been
adjusted, the Track
00 flag adjustment (Section
4.11.8), Track 00 stop (Section 4.11.7) and R/W
head azimuth (Section 4.11. 9 )
must be checked.
4.11.3 ReadlWrite Head load Button: Removal
and Installation
a. Remove side cover if installed.
b. To remove the old
button, hold the arm out
away from head, squeeze the locking tabs
together with apair
of needle nose pliers and
press forward.
c. To install load
button, press the button into
the arm, from the head side, and it will snap in
place. Reference Figure 10.
FIGURE 10

d. Adjust according to Section 4.11.4.
Note: The load arm should never be opened
over 90° from carriage assembly or while
at track
00 to preventpossible damage to
the torsion spring.
4.11.4 Read/Write Head Load Button
Adjustment
a. Insert Alignment Diskette (SA120).
b. Connect oscilloscope to TP 1and 2, added
differentially and sync negative external on
TP 12
(- INDEX).
c. Step carriage to.track 75.
d. Observing read signal on oscilloscope, rotate
the load
button counter-clockwise in small
increments (10°) until maximum amplitude is
obtained.
4.11.5 Head Penetration Adjustment
Note: This adjustment is not normally done in the
field. The only time that this adjustment
need be done
is when the stepper mounting
plate has been loosened or removed.
a. Place the penetration tool (PIN 50380) on the
gauge block and insure that the gauge reads
.030 (3 on the small hand) and zero the dial
for the large hand. This results in areading
of
.030".
EVEN AMPLITUDE (100%), ON TRACK
LEFT 80% OF RIGHT, +1 MIL OFF TRACK TOWARD TK 0
LEFT 60% OF RIGHT, +2MI L OFF TRACK TOWARD TK 0
LEFT 40% OF RIGHT +3 MIL OFF TRACK TOWARD TK 0
RIGHT 80% OF LEFT, .. 1 MIL OFF TRACK TOWARD 76
RIGHT 60% OF LEFT, - 2 MIL OFF TRACK TOWARD 76
RIGHT 40% OF LEFT, - 3 MIL OFF TRACK TOWARD 76
Figure 11 R/W Head Radial Alignment
13

b. Swing open the cartridge as per Section 4.3.
c. Place the
penetration tool on the base assembly
with the short leg
on the platen, the long leg
on the carriage guide bar, and the plastic tip in
the
center of the R/W head.
d. The head penetration should be .030" ± .003"
read on the gauge.
e. If the head does not meet this adjustment,
move the stepper plate laterally
until the gauge
reads
.030".
f. Tighten the screws and recheck the adjustment.
g. Return cartridge guide and adjust as per Section
4.9.2.
h. Adjust Azimuth (Section 4.11. 9).
4.11.6 Track 00 Detector: Removal and
Installation
a. Remove side cover (Section 4.2).
b. Swing cartridge guide
open (Section 4.3).
c. Manually rotate stepper shaft and move carriage
all the way
in.
d. Remove 2screws holding bracket to base cast-
ing and remove bracket and detector.
e. Remove PCB connector and remove PCB.
f. Extract cable from P2 connector; Brown, A
(Rl); Black, C(R3); Red, F (R6); and Orange
K(R9).
g. Remove cable clamps and remove Detector
assembly.
h. To install, reverse the procedure.
i. Adjust according to Section 4.11.8.
4.11.7 Track
00 Stop Adjustment
a. Remove side cover (Section 4.2).
b. Step carriage
to track 00. Verify that carriage is
at 00 by checking PI pin 42 is minus (ground).
c. Check that stop is .040" ± .020" between collar
and carriage.
Turn DC power OFF, and
manually
rotate lead screw clockwise until
carriage stops. Check
that stop is .020" ± .010"
between collar and carriage.
14
d. If clearances are not within tolerance, continue
on with adjustment procedure.
e. Turn DC power ON.
f. Step carriage to track 02.
g. Loosen Track 00 stop collar.
h. Grasp
end of lead screw, in back of stepper
motor, with apair of pliers and manually turn
lead screw clockwise to the track -01 position.
(Next
detent position on stepper motor.)
i. Position the stop collar axially along the lead
screw
so there is .020" ± .010" between collar
and carriage.
Rotate the collar toward inside
until the stop
on the collar contacts the carriage
stop surface. Tighten screw.
j.
Turn DC Power OFF and back ON. Carriage
should move to track
00. Verify that there is
data at track 00.
k. Step carriage between track 00 and 76 and
check for any binding or interference between
the carriage, lead screw, stop and head cable.
4.11.8 Track 00 Flag Adjustment
a. Remove side cover (Section 4.2).
b. Check head radial align'ment and adjust if
necessary before making this adjustment.
c. Connect oscilloscope probe to TP 26. Set
vertical def1ection to 1 v/division and sweep
to continuous.
d. Step carriage to track 01. TP 26 should be high
(+5 volts).
e.
If TP 26 is not high, loosen screw holding Track
00 flag and move flag towards stepper until
TP 26
just goes high.
f. Step carriage to track 2. TP 26 should go low.
Adjust flag towards spindle
if not low.
g. Check adjustment by stepping carriage between
tracks
00 and 02, observing that TP 26 is low
at track 02 and high at tracks 01 and 00.
h. Replace side cover.