Shugart SA800 User manual

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© Copyright 1977 Shugart Associates

TABLE OF CONTENTS
Section
Maintenance Features
Page
2
3
4
5
6
7
8
9
Diagnostic Techniques
Preventive Maintenance.
Removals Adjustments .
Physical Locations . .
SAS09Exerciser Connections
SASOO/SOl PCB Component Locations
SASOO/SOl L.ogic Manual. . .
SASOO/SOl Schematic Diagrams
3
5
7
17
21
22
23
31

1.0 MAINTENANCE FEATURES
1.1 Alignment Diskette
The SA 120 Alignment Diskette is used for align-
ment of the SA800/80I. The following adjust-
ments can be made using the SA120.
1. RjW 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 1f + 2f signal for load pad adjustment.
Caution should be exercised in using the
SA 120
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 aPCB 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 SA800/80 1drives, when used with the SA 120
alignment diskette.
The exerciser has
no intelligent data handling
capabilities
but can write both 1fand 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
I.
Description
AlignmentDiskette
Cartridge Guide Adj. Tool
Head Penetration Gauge
Load
Bail Gauge
Exerciser
Spanner Wrench
Part
Numher
SA120-1
50377-1
50380-0
50391-0
SOC) 19-0
50752-0

3
2.0 DIAGNOSTIC TECHNIOUES
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 11 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:
I. Reread the track ten (10) times or until such
time as the data is recovered.
2. If data is not recovered after using step] ,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
I. Stepper malfunction.
2. Improper carriage torque.
To recover from aseek error recalibratc to track
00 and perform another seek
to the original track.
TP
2
3
4
5
6
7
10
II
12
16
21
24
25
26
27
Read Data Signal
Read
Da ta Signal
Read Data (Differentiated)
Read Data (Differentiated)!
Signal Ground
Signal Ground
Signal Ground
-Index
+Head Load
-Index and 80 ISector Pulses
+Read Data
-Data Separator Time +I
-Data Separator Time +2
+Write Protect
+Detect Track 00.
+Gated Step Pulses
2.7 Test Point Locations
1 • •
••
J5
10
••
11
0
7J2
P2
025
26 0
012 A
20
P1
J1
•
~
J6.
27 •
49
0
V
21
10
0 0 16
0
0
24
21
0010
~
0
6
J3i
04350
000P3
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 satisfactorily.
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.
uns
ment
reas
ws,
es
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 b
Lead Screw
12
and dirt
Belt
12
Frayed or weakened a
Base
12 Clean base Inspect for loose scre
connectors, and switch
Read/Write Head
12
Check for proper align
*Assumes normal usage Figure 1PM 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/Index LED Assembly: Removal and
Installatlion
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
Installatiion
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' (IA), Black to 'E' (R5) and White
to
'J' (R8).
4.5.1 Write Protect Detector Adjustment
a. Insert SA 101 diskette in to 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
L.oad 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.
4.61.2 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 thatthe 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.
l. Energize Head Load Coil and step carriage
between track
00 and 76. Insure that there is a
clearance
of a minimum of .010" between Head
Load Bail
and Head Load Arm.
j. Replace side cover.
UP STOP
ADJUSTMENT
ISCREW
FLUSH WITHIN ±.005
~~--\~b=T=~=O=--L~1
R/W HEAD ..-----.' "\
FIGURE 2 HEAD LOAD ACTUATOR UPSTOP
ADJUSTMENT
ADJUSTMENT
==-~ -~~- SCR EW
~,-=E=~=:=·~~=~:I~~ D~i~{~:~05
BASE CASTING PLATEN---.
FIGURE 3 HEAD LOAD ACTUATOR DOWN STOP
ADJUSTMENT

4.6.3 Head Load Actuator Timing
a. Insert Alignment Diskette (SA 120).
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 input
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 J~ssembly:
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 (SA120).
b. Using oscilloscope monitor TP-I2 (-Index),
sync internal negative, DC coupled, set vertical
scale
to 2V/cm.
c. Adjust the potentiometer on the Sector/Index
Phototransistor
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 (SA 120).
b. Step carriage to track 01.
c. Sync oscilloscope, external negative, on TP 12
(- Index). Set time base to 50 Ilsec/ division.
d. Connect one probe to TP 1and 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 J1sec. Insure that
the transducer assembly is against the registra-
ltion 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 ±1 00 J1sec.
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.flbs. If spring washers are
used, insure they are compressed. Add a drop
of LOCTITE® #290 to threads.
4.8.1 Clamp Hub Removal
a. Remove hub clamp plate. Reference Figure 6.
b. Remove damp hub and spring.
c. To install, reverse the procedure. No adjustment
necessary.
CARTRIDGE
GUIDE
ADJ. TOOL
MOUNTING
SCREW
ADJUSTING
SCREW
FIGURE 6 CARTRIDGE GUIDE ADJUSTMENT
10
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
'----,-L.--:J-------::J
~~ ~=c
FIGURE 7 CARTRIDGE GUIDE REMOVAL
4.9.2 Cartridge Guide Adjustment
a. Insert the shoulder screw (tool PfN 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.
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.
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-12 (-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 output 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 (Section 4.2).
c. Extract stepper cable contacts from P2 connec-
tor. Black 10 (LI 0), Red 2(L2), Brown 5(L5),
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 GL YPTOL.
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
procedurc. Notc steps "h" and "i".
h. If installing a new 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.
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 un til the flag is clear of the
detector.
c. Insert the SA 120 alignment diskette and load
the head. Set the scope as explained in Section
4.11.3 steps c and 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
ht~ad radial adjustments. Refer to Section4.11.3.
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 (SAI20).
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 Iand 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 cl ockwise 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 Alignment has 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 prevent possible damage to
the torsion spring.
4.11.4 Read/Write Head Load Button
Adjustment
a. Insert Alignment Diskette (SAl20).
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, +2 MI 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.
c. [f 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" be tween 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, con tinue
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 a pair 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
un til 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 alignment and adj ust if
necessary before making this adjustment.
c. Connect oscilloscope probe to TP 26. Set
vertical deflection to 1v/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 nag 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 0I and 00.
h. Replace side cover.

4.11.9 R/W Head Azimuth Alignment
This adjustment can only be made on SA800/801's
at
MLC 3or higher with anew style stepper plate
which has 50112-4 stamped
on it. This adjustment
is only necessary when the stepper or carriage
assembly has been replaced or
if the stepper plate
has been loosened.
a.
If stepper plate has been loosened or replaced
adjust head penetration, Section 4.11.5.
b. Align R/W head, 4.11.3.
c. Install C.E. alignment diskette
SA 120-1. Select
the drive and step to track 76.
d. Sync the scope external negative on TP 12, set
time base
to .5 MSec per DIY.
e. Connect one probe to TP 1and the other to
'IP 2. Invert one channel and ground the probes
to TP 5&6. Set
the inputs to AC, ADD and
50
MY per division.
f. Compare the wave form to Figure 13. If not
within the range shown the head Azimuth will
require adjustment.
If required, proceed to
next step.
g. Slightly loosen the 2R.H. stepper plate mount-
ing screws only. Reference Figure 12. Do not
loosen the L.H. screw as this will effect the
head penetration adjustment.
FIGURE 13
h. Push the stepper down towards the A.C. drive
motor until the 1st sector is larger than the 2nd
sector.
i. Pry the R.H. side of the stepper plate up with a
medium screw driver until the 1st and
4th
sectors have equal to or less amplitude than the
middle 2sectors. Reference Figure 13.
15
I, C:LI~I MOTOR CAPACITOR
STEPPER PLATE
(P/N50112-41 1'f
'
00~111 R.H.STEPPERPLATE
M
MOUNTING SCREWS
L.H. MOUNTING ~0
SCREW (DO NOT I ~
LOOSEN) ~
[]
~""" &i!~'~:ATTH",mNT
AC DRIVE MOTOR~ TO OBTAIN THE PROPER
ADJUSTMENT
DRIVE REAR VIEW
FIGURE 12
j. Re-tighten the 2R.H. screws. If either of the
outside 2sectors increase in amplitude greater
than the inside 2after re-tightening the screws,
perform the adjustment again.
k. Check and re-adjust the index timing and head
radial adjustment
if required.
4.11.10 Stepper Plate Removal and Adjustment
a. Remove PCB.
b. Remove head and carriage assembly from
stepper lead screw, section 4.11.1 .
c. Pull the stepper
motor out thru the stepper
plate until the lead screw
is completely clear of
the plate.
d. Remove the 3stepper plate mounting screws.
e. Reinstall the stepper plate.
NOTE:
If the stepper plate is P/N 50112-4,
there must be anylon bushing in the L.H. hole
and all 3screws must have aflat washer and a
black spring washer.
f. Reinstall head and carriage and stepper motor
assemblies.
g. Adjust penetration, Section 4.11.5. If the
stepper plate
is P/N 50112-4, there will remain
agap between the
bottom of the stepper plate
and
the machined surface on the casting. All
other style stepper plates must remain flush
with machined surface.
h. Readjust carriage assembly, Section 4.] 1.2.
i. Check and adjust Azimuth alignment, Section
4.11.10.

4.12 Activity Light Removal and Installation
(Standard)
a. Remove P6 connector from PCB.
c. Remove
front plate (Section 4.10).
b. Remove two screws holding assembly to front
plate.
b. Remove cable clamp holding
the cable and
remove cable from clamp.
c. Remove two allen head screws holding assembly
to push
button.
c. Remove the 2screws holding the push button.
d. Remove push button and activity light from
the front
as an entire assembly.
d. Grasp
both ends of push bu tton and bow
outwards to remove LED.
c. Reverse procedure to assemble.
e. Install the light and push button assembly
by reversing the removal procedure.
f. No special orientation is required when
installing P6
onto the PCB. No adjustments
are required
to the push button assembly.
f. Adjustment
of the door lock should not be
necessary. If it has to be. the gap between the
armature tab
and the latch should be .015
±.010. This adjustment can be made by
loosening the two screws on the armature.
4.13 Door Lock
a. Disconnect P6 connector.
4.14 Activity Light (with Door Lock Option)
b. Disconnect red wire near IC 2G.
a. Follow procedure for door lock (4.13).
LED
,,---*"" (l3LK)
L.-- ~tI_ SOLENOID (2)
(BRN)
GROUND
(B LK) "*"---------1
+5 VOLTS SOLENOID(1)
(RED) *-------4~------~ (FlED)
INUSELED
(BRN)
DOCK 25058·- II
~rJ$$@
t;J RED BRN BLK
FIGURE 14 DOOR LOCK SCHEMATIC
16