Panasonic JU-455-5 User manual

•
erv1ce
Panasonic
ORDER NO. MSD850902900
anua
Flexible Disk Storage Drive
JU-455-5
Matsushita Communication
Industrial Co., Ltd.
Memory Systems Division
3-1, 4-chome, Tsunashima-Higashi
Kohoku-ku, Yokohama 223 JAPAN

1.
2.
3.
4.
s.
6.
7.
B.
9.
10.
CONTENTS
PARTI
INTRODUCTION ···..···..· ...... ······ .. ···..···· .... ··· .... ····•· ·..·· ..... · .. ·..···· .. · .... ····..·..·· .. ·..• .... ·..··..·..····•···
MODELS AND MDODEL NUMBERS ............ · .... · ........ • ........ · ........ · ............ · ............ · .... · ....... ·..···....
SPECIAL TOOLS' ................................. '..' ............. ' ...................................... '' ... ' ...... ' ............ '..
OUTLINE OF MAINTENANCE ...···· .... ··• .... ·..··· ... ·..·· .... ····..·..·····..·•· ... ··..· ................. · ..... ··· ··· ···· ... ···
DIAGNOSTIC PROCEDURES · ... ·····..··· ... ·· ..... ·•· ... ····· .......... · •· ·. · ·' ... · ................... ' .......................... .
5.1 Error Symptom Recognition ............................................................................................. .
5.2 Soft Error Detection and Correction ................................................................................. ..
5.3 Write Error·· .. · .... · ..... ·· ........................................... ··..·· ...... · ...... · ................................ ..
5.4 Read ErrOr····
00
••••••••
00
·•··
00
•••••
00
• ................................................................................... ..
5.5 Seek Error .............. ·•· ............ ·..·•· .............................................................................. ..
5.6 Compatibility Error ··· •· ··..····..· ...... ···· ........... · ..... ··· .............................. · .... · ..... · ........... ··..
TROUBLE ANALYSIS ·..· .... · ...... · .... ··· .... ·..· .... ·..· .... ·.. · .... · .............. · .... ·..·· .. ·..· ........ ·..· .......... · ...... ·
6.1 Trouble Analysis Procedure · .................... ··· ....... · .................... · ...... ···..· ..... ·· ..... ·..··· ...... · .. ·
6.2 Trouble Shooting ...... ··· ....... ··· ............ · ....... · ..... ··..·..·..· ........ ·· ...... ···· ....... · ........ ··..· .... ··..
6.3 Trouble Analysis Table .... ·· .......... · ......... ·..· .... ·.. · .... ·.. · ....... · ........... · .... ·..· .... · .... ·· .............. ..
PREVENTIVE MAINTENANCE .. ··..· .... ·•..·..· .... · .... ·..···· .. · .... · .... · ...... ·..· .... ··· .... ·· ...... ·..·..·..· ...... · .... ·..·
MEASUREMENT ITEMS FOR EACH MODEL ..· ...... ·· ........ ·..· ........ · ... ·· ... · ........................................... ..
ADJUSTMENTS AND VERIFICATIONS ..................................... ··· .... ·· ............ ·· ........ ··· ......... · .... ·····
9.1 Motor Speed Adjustment and Verification (Index Period) ........... ··· .......... ··· ..··· ..... ··· ... ··· ....... ··
9.2 Write Protect Verification ...................................... •· ............ ·..·..··..···..· .... ··· ... · ...... ··· ..... ..
9.3 Head Output Verification ............................................................................................. .
9.4 Output Modulation Verification ................................................ ·•· .... ···· .... ······ .... ····· ...... ··
9.5 Radial Alignment Adjustment ·..····..·····..· .... ········..···..······ ..... ···• · .... ·······..·· ... ·· ... ···..···..··..··
9.6 Azimuth Verification ·.···..· ....... ··..··· ..... ·•···· ....... ····· ... ····· ....... · .... ·· ......... · .... · ...... ·..···..· .. ·
9.7 Index Burst Verifications ................................................................................................ .
9.8 Track 00 Sensor Adjustment· ............ ·•· ................. ····· ...... ·· ........ ·· .................................... ··
9.9 Limiter Verifications (5.25·inch)·· ... ·· ··· ............ ·· .......... ··· ....... · ..... ·· .................................... .
9.1 O limiter Adjustment(3.5-inch) · ..... · ......... · .... · ........... ·..·····..· ... ··· .............. · .. ·· ............... ····....
9.11 Asymmetry Verifications ...... ·..· ..... ··· .. · •· ... ·· .................... · .... · .... · ....... ··· ......... · ...... ·..··· · .... .
PANASONIC ALIGNMENT DISKETTE ... ·· .... ·..· .... ···· ....... · ........... · .... · ..... ··..···· .... ·····..···..· ... ··..···..···..·
PARTll
Page
1
1
2
2
2
2
3
3
3
3
3
3
4
5
5
6
7
7
7
7
8
8
10
10
11
11
11
11
12
11. REMOVALSANDINSTALLATIONS
00
•
00
............................................................................................ 13
11.1 PCB Removal and Installation............................................................................................. 13
11.2 FrontPlate Removal and Installation................................................................................... 13
11.3 Track 00 Assembly Removal and Installation· ..................................... • .............. •..• .............. · .. • 13
11.4 CollectAssembly Removal, Installation and Adjustment............................................................. 14
11.5 Clamp Assembly Removal and Installation............................................................................. 14
11.6 Write Protect Sensor/Index DetectorAssembly Removal and Installation......................................... 15
11.7 CartridgeGuideAssembly Removal and Installation.................................................................. 15
11.8 Stepper Motor Assembly Removal and Installation................................................................... 16
11.9 CarriageArm Assembly Removal and Installation.................................................................... 16
11.10 Drive Motor Removal and Installation ................................................................................ • 17
11.11 LED Assembly Removal and Installation .......................................................... ·.. .......... ........ 17
12. TEST POINTS ............................................................................................ ·•· ..... •· ..·..·..··· ..... ··• 18
13. EXPLODEDVIEw..................................................................................................................... 19
14. REPLACEMENT PARTS LIST ........................ •..·•·.. ·•··· ................... ·· ... •· .......... · ....... ···... ·•• .... ·.. ···... ·• 20
1 S. REPLACEMENT PARTS LIST OF PCB ................................................... ·.· .. ···· .. · .... • .... · ..... ········ .... ·..·•· 21
16. SCHEMATIC DIAGRAM.............................................................................................................. 22
17. CIRCUIT BOARD ..................................................................................................................... 23
18. BLOCK DIAGRAM ·..·•· •· ..... · .................................... •·••·· ............. ····· ........ ·• ........ ••· ....... · .... ··· ..... · 24

PART. I
1. INTRODUCTION
This service manual consists of two parts, Part I covering maintenance description, adjustment procedures, and trouble
analysis and Part II disassembly and reassembly procedures parts list, and PCB circuits.
Part I encompasses maintenance instructions for all FDD models. Refer to the applicable items, and perform maintenance
work on the FDD.
2. MODELS AND MODEL NUMBERS
2.1 5.2S:·fnch FOO
2.2 3.5-inch FOO
3. SPECIAL TOOLS
s;.zs0inmF00:1--..--- 48TPt --...-L-- JA-55X
JlJ.455
LJA-550
JA-551
3.5-inch FOO
JU-58X ----- JU-581
l__JU-585
JU-59X --~-- JU-591
l__JU-595
JU-465
JU-475
67,5TPI----- JU-31X 1=JU-312
JU-313
JU-314
135TPI LJU·32X --~-- JU-322
LJU-323
JU-324
JU-36X 1=JU-362
JU-363
JU-364
The following special tools are used for FOO maintenance.
TABLE 3.1
Tool
Exerciser
Alignment diskette
Work ... ~i<ette
CMOSmL adaptor
Lim miter Adfust Tool
(S.25-inch)
Oscilloscope (SO MHz)
Probe(10:1)
Frequency counter
Note: ;::-:Stand for the same as left.
Part No.
5.2S-incn(96TPI)
JA·S6x/JU-465
817-560 817-581
: DAD (Dynamic Alignment Diskette) - 1 -
3.5-inch
JU-01AA
(DAD only)
2DD
YTFDD-CN3S
Quantity
1-2
1-2
3

4. OUTLINE OF MAINTENANCE
• The following tools are required for maintenance of aFloppy Disk Drive. (FOO)
4.1 Alignment Diskette
Alignment diskette 1s used for head actuator alignment and index sensor adjustment.
• Adjustments (Refer to table 8.1)
(1) Specify an applicable model from Tabel 8.1, and make a read/write head radial adjustment at a specified track.
(Sides 0, 1)
(2) Make an index timing adjustment at aspecified track. (Sides o, 1)
(3) Make an azimuth measurement at aspecified track. (Sides O. 1)
CAUTION
Do not write when using alignment diskette. Check that write protect sensor is properly operating.
4.2 Exerciser
The exerciser enables you to make all adjustments and inspections necessary for an FOO. Its functions include the
following:
( 1) Seek increment or alternate tracks
(2) Read (but no data compare)
(3) Write 1F or 2F (AllO'sor1's)
(4) Head load ( 5.25-inch FOO with optional head loader)
(5) Recalibration to track 00
The exerciser has switches and indicators to execute a specified function.
5. DIAGNOSTIC PROCEDURES
5.1 Error Symptom Recognition
Errors that occur because of the wrong operating procedure, wrong programming, or use of a defective diskette, or soft
errors due to external causes, such as contaminated air and random electrical noise, are often attributed to a drive
failure or maladjustment. .
Unless a visual inspection of the drive reveals an evident assembly fault or adefect, always confirm errorswith another good
diskette, and another known good drive.
5.2 Soft Error Detection and Correction
Soft errors are normally caused by the following:
(1) Contamination between read I write heads and diskette. This kind of contamination can be easily eliminated by the liner in
the diskette.
(2) Random electrical noise, normally a few microseconds or less.
(3) Small defects in written data and I or track not detected during write operation may cause soft errors during read.
(4) Faulty grounding of the drive o~ · st system can also cause a soft error.
(5) Wrong motor speed is another cause of soft errors.
Take the following steps on the controller side to recover from the soft errors mentioned above.
(1) Read the track again ten times or until the data is recovered.
(2) If Step (1) above fails to recover the data, access the adjacent. Then return the head to the original track.
(3) Repeat Step (1 ).
(4) Any error that cannot be corrected by the above procedure is irrecoverable.
- 2 -

5.3 Write Error
If an error occurs during write operation, it is usually detected during the next revolution by performing a read opera-
tion called write check. To correct an error, write again and repeat a write check operation. If the result is unsatis-
factory after ten or more write operations, perform a read operation on another track to determine whether it is the
diskette or the drive that is wrong. If an error persists, replace the diskette and repeat the above procedure.
If the error still persists, consider the drive defective. If the error is corrected, dispose of the diskette as defective.
5.4 Read Error
Most read errors are soft errors. Data can be recovered by following the recovery procedure mentioned in 5.2.
5.5 Seek Error
(1) Stepper motor or stepper motor drive circuit fS fault',1.
(2) Faulty carriage
There are two ways of seek error recovery. One is to recalibrate to track 00, and seek back to the original track.
The other is to read the ID field, cbeck the track number on which the head is located, and move the head away
from 1t. And read it again.
5.6 Compatibility Error
The data which is written by one drive may not be read by another. This error is called a compatibility error, which
can be caused mostly by the following. The check points are also mentioned below:
(1) Head misalignment: Refer to (Adjustments and Confirmation Item 9.5)
(2) Head output too low: Refer to (Adjustments and Confirmation Item 9.3)
(3) Motor speed difference: Refer to (Adjustments and Confirmation Item 9. 1)
6. TROUBLE ANALYSIS
To determine the cause of trouble whether it lies in the FOO, diskette, or controller, replace the disk and FOO with
good ones. If the FDD is assumed faulty as a result, follow the procedure below.
6. 1 Trouble Analysis Procedure
FDD trouble may occur in any of the following ten forms.
(1) Index detection failure
(2) Not ready
(3) Track 0 undetectable
(4) No seek
(5) No write
(6) No read
(7) Read error
(8) IN USE LED won't light.
(9) Write protect undetectable
(10) No head load 15.25 ·inch FOO with optional head loader)
Check with the troubleshooting flowchart in 6.2.
CAUTION:
Be su•e to switch power off before removing an i:oo or PCB from the operating system.
- 3 -

6.2 Trouble Shooting Flow Chart
START
Run the operating system
and check. Record all
diagnostic information on
tracks ana sectors as far as
the ram rmits.
Install Exerciser on FOO
Power SW
DC SW ON
Drive Select SN
head load SN
ON
RECAL SW
ON
NO Media Defective
Controller
Defective
Check Item 1.
Table 6.1.
Check Item 2,
Table6.1.
Check Item J.
Table6.1.
Check Item 4,
Table 6.1.
-4-
Set Address SW
to Track
Write SWON
Write SW OFF
FOO online test
ENO
NO
NO
Check Item 5,
Table 6.1.
Check Item 6,
Table 6.1.
Check Item 7,
TableJ.1.
Check Item 8.
Table 6.1.
Check Item 9.
Table 6.1.
Check Item 1 O.
Table 6.1.

6.3 Trouble Analysis Table Table
6.1
Item
Trouble No.
Cause
5.25-inch
JU-3x3, 3x4
JU-3x2
1
Index detection
1
Collet part fau.!.!Y_
I
R~ace
:..:----:-----
----
failure 2 DD
motor control PCB
Replace Replace
DD motor,
Replace DD motor
assembly
3
DD motor faulty
! Replace Base
assembly
4 Index LED faulty Replace Replace
DD motor,
Replace
5
Index detector faulty Replace Base assembly
6
Index LED/index detector installation faulty
Adj.
~
---
:
7 PCB motor ON circuit Repair lii -
'"'
-
8
PCB index detection circuit
Repair
~:;
-
,.,
-
2
Not ready 1 See Item 1.
2 PCB ready circuit Repair
?i~
-
...
-
3
Track 0 detection 1 Track
00 assembly
Replaa
?.:
-
'"'
-
farlure 2
PCB track 0 detection failure Repair
;?~
-
,..
-
4 No head loading 1 See Item 1.
2 See Item 2.
3
HDL solenoid Replace
---- ---
4
PCB HDL circuit Repair
...
-,
..
-
5
No seek
1 Stepper
motor
Replace
,..
-
/•'·
-
2
Guide shaft contamination or damaged
Replace ,
..
-
'"·
-
3
PCB stepper driver circuit
Repair
...
-
..
-
6
No WRITE 1 See Item 1.
2 See Item 4.
3 Head disconnected Replace·
...
-,
..
-
4 Head shorted Replace·
/••
-
...
-
5
HDL bail height wrong
Adj.
-----------
---
6
PCB write circuit
Repair
,.,
-,
•..
-
7
No READ
1 See Item 1.
2 See Item 4.
3 See Item 6.
4 PCB read circurt
Repair ...
-,. -
8 READ ERROR 1 See Item 1.
2 See Item 4.
3 See Item 17.
4 Alignment
Adi.
...
-
...
-
5 Azimuth
Unadjustable
...
-.
..
-
6 Burst Adj,
Unadjustable Unadjustable
7 Asymmetry
Adj. Adj.
---
8
Limiter
Unadjustable
Adj.
Adj.
9 FlagO
Adj.
::~
-
,.,
-
10
HDL time
Adj.
~
-----
11 Index period
Adi.
Replace DD motor,
Replace
Base assembly
12 PCB read circuit
Repair
...
-
?:~
-
9
IN USE LED 1
LED part
Replace
'"'
-
'"'
-
won't light.
2 PCB IN USE circuit
R&pair
'"'
-
10
Write protect
1
Write protect part
Replace Aeol•c•
DO motor. ea ..
Replace
failure H
.. fft~
2 Write protect circuit
...
-,., -
Note: ;;: ~: Stand for the same as left.
7. PREVENTIVE MAINTENANCE
No preventive maintenance is necessary for any type of FOOs under normal conditions of use.
- 5 -

8. MEASUREMENT ITEMS FOR EACH MODEL
Table 8.1
Item Parameter JU-312, 313, 314 JU-32X,36X JU-581, 585
TRK Value TRK Value TRK Value
1 Index period
20
200±3ms 40 200±3ms 32 166.7:!:
0.2 ms
2
Output level
39
160 mVor 79
180mV or
76
120 mVor
more more more
3 Radial Alignment
20
75% 40 50%
32
70%
4 AZIMUTH
20
:!: 18' 40 :!: 18' 68 ± 18'
5 Index burst
20
3±1.Sms 40 3± 1.Sms 68 200:!:
200µs
6
FLAGO From track 1 1: 1 From track 1
1:1
From track 2 1:1
to track 2
to track 2 to track 3
and back and back and back
7 Limiter -1
Recalibrate -1 Recalibrate -1 Recalibrate
and return to and return to and return to
0 0 0
8 Asymmetry 39
<600ns
79
<600ns 76 <350 ns
9 Head load
time <SO ms
Item Parameter JU-591, 595,475 JU-455/465 I JU"455·5
TRK VALUE
TRK
Value
I::
TRK
Value
1 Index period
32
166.7± 16132 200±0.2 ms
1::
t6
200±.0:2ms
0.2ms
200±
(High)
•••••
0.2ms
·.·
(Low) ..
2
Output level 76 120 mVor
39ng
140/120 mV
39
--C·.
140/mVor
more
or more more
3 Radial Alignment
32
70% 16132 70%
"..:;.
T6
70%
4 AZIMUTH
68 ±18' 34/68 ±18'
I>
3:4 ±18'
5 Index burst 68 200±
34/68
200± 34
200±
200µs 200µs
200µs
6
FLAGO
From track 2 1: 1 From track 1 1: 1
Fromtrack2 1:1
to track 3
to track totrack3.
I
-and back 2/track 2
to
and: back·
track 3and
back
7 Limiter
-1 Recalibrate -1 Recalibrate
-·l . Recalibrate
and return to
and return to
I··
and return to
0 0 0
8 Asymmetry 76
<350 ns 39n9 <600 ns
39
<600ns
9 Head load
time
<SO ms
<SO ms
-6-

9. ADJUSTMENTS AND VERIFICATIONS
9.1 Motor Speed Adjustment and Verification (Index Period)
( 1) Insert a diskette, run the motor, and clamp. Refer to the index period column of Table 8.1 for the applicable
model.
(2) Step to the specified track.
(3) Connect a frequency counter to the INDEX signal.
5.25-inch: TP7
3.5-inch: IX
(4) Check that the frequency counter readings meet the specifications in the table.
(5) Adjustment
5.25-inch: Turn the speed control potentiometer on the motor control circuit board until the specificatisons are satisiied.
3.5-inch: No adjustment
9.2 Write Protect Verification
(1) Check that the exerciser's write protect lamp goes on and off as a media is inserted and removed as specified in the
table below.
Media with write protect Media with write protect
hole open hole closed
5:25-inch OFF ON
3.5-inch ON
OFF
9.3 Head Output Verification
Use anew diskette if possible to identify head failure forthis check.
( 1) Insert a good diskette.
(2) Run the motor.
(3) Step to the track specified in the output level column of Table 8.1.
(4) Connect the oscilloscope probe as specified below.
CHl
CH2 EXT
S:.25·inch TP1 TP2 TP7
3.S·inch T1
T2
IX
(INDEX)
Invert channel 2 and select the Add mode.
Set vertical deflection to 10 mV /division and horizontal deflection to 20 ms/division.
(5) Write 2F (all ones) on the entire circumference.
(In case of a double-sided FOO, repeat it on sides 0 and 1 using SIDE SELECT.)
(6) Check that the average output level meets the specifications of Table 8.1. If it does not meet the specifications,
refer to Item 7 of the Trouble Analysis Table.
- 7 -

9.4 Output Modulation Verification
Modulation: M is calculated by the following formula.
Vmax-Vmin
M(%)= x100 using the value obtained in 9.3, and check that the
Vmax+ Vmin
calculated value is 20% or less.
-----=--- ---~l!!'lm'------?'-r--- Maximum Voltage Valve : Vmax
-------------------- --.._"<- ... 7--,c_----Average Voltage
Minimum Voltage Valve : Vmax
Fig. 9.1 Modulation
9.5 Radial Alignment Adjustment
Introduction
This adjustment is normally not necessary.
If the mounting screws for the stepper motor loosen, or if parts become defective, or if a compatibility error occurs, check and readjust
according to the following procedure.
Steps (4) to (9) should be performed regardless of the type, CE or DAD alignment diskette used. Use an alignment diskette suitable to
the type of FDD to be adjusted according to table 3.1.
(1) Insert an alignment diskette.
CAUTION:
Be sure to leave the alignment diskette under room conditions for 20 minutes before adjustment.
(2) Step to the track specified in the Radial alignment column of Table 8.1.
(3) Leave the oscilloscope in the same condition as mentioned in section 9.3.
• Cats Eye System S.25-inch
(4) Check the output waveforms for sides 0 and 1. They should appear as in Fig. 9.2.
(5) The two waveforms should appear in the amplitude ratio in the R/A column of Table 8.1 or better.
(6) If the specified ratio is not satisfied, loosen the two mounting screws for the stepper motor.
(7) Move the stepper motor along the base by hand until the two waveforms assume approximately the same ampli-
tude, and retighten the mounting screws. (See Fig. 9.2.)
(8) Step the head outward (track 0) and inward (track 40 or 79), and confirm that the adjustment has been completed.
(9) After the radial adjustment, be sure to confirm track 00 sensor adjustment 9.8 and carriage limiter 9.9.
-8-

A>B
:! x 100
B >A
: ~ x 100
Fig. 9.2 Radial Alignment Waveforms (CATS EYE)
Note: Sides O and 1 are adjusted to agree at the factory, If they diugree, adjust them to meet the specifications of Table 8.1
• DAD (Dynamic Alignment Diskettel 3.5-inch
(4) Watch the output waveforms for sides 0 and 1. They should appear as shown in Fig. 9.3.
(5) Measure the timing levels A1 to A4 and B1 to 84 in Fig. 9.3, and calculate the lobe ratio from the followi
formulas.
~B
~A >~B : ~A x 100%
~A
~ A <~B : ~B x 100%
(6) The lobe ratio calculated by the above formulas should meet the specifications on item 3 of Table 8.1.
(7) If the above requirement is not met, loosen the two mounting screws for the stepper motor. adjust.
(8) Seek from track 0 to track 40 and from track 79 to track 40, and confirm that the adjustment has been complete
(9) After the radial adjustment, be sure to confirm track 00 sensor adjustment 9.8 and head carriage limiter 9.9.
Note: An alignment instrument for 3.5-inch FDDs permits accurate and easy adjustment because the lobe ratio is displayed c
the instrument.
Index
burst
'NllYeform
Azimuth
~veforms
:j
i~
A,
e,
Radial alignment W9Wforms
s,
A,
e,
r
A
A,
e.
Fig. 9.3 Alignment Waveform (DADI
-9-

9.6 Azimuth Verification
(1) Insert an alignment diskette. Seek to the track specified in the azimuth column of Table 8.1.
(2) Set the oscilloscope in the same conditions as in 8.3, and set horizontal deflection to 0.5 ms/division.
(3) Measure as shown below.
(4) Confirm that the measured value meets the specifications in the azimuth column of Table 8.1.
B c
B c c D A B
A D A
Azimuth 0 waveforms
D
CaseofB>C
B-C
Azimuth ,. B=o x (A)
CasaofB<C
Azimuth .. CC -8 x (A)
-A
9.7 Index Burst Verification
3.S·inch (A) : CE - 30'
OAD-15'
Fig. 9.4 Azimuth Waveforms
s:2s~fricn (AL: 12'
(1) Insert an alignment diskette. Seek to the track specified in the 1/8 column of Table 8.1.
(2) Set the oscilloscope time base as follows:
s:;is;inch: 50µs/division
3.5-inch: 1 ms/division
(3) Check that the time from oscilloscope start to the first data pulse meets the 1/8 specifications of Table 8.1. (DAD
system)
(4) If the specifications are not met, adjust as follows. (No adjustment necessary for 3.5-inch models)
• Loosen the index detector mounting screws enough to free the assembly.
• Adjust the timing to 200 ± 200 µsec.
• Retighten the screw.
• Check the timing again.
I• Index. Burst .,
1
Fig. 9.5 Index Timing
- 10 -

9.8 Track 00 Sensor Adjustment
( 1) Set the oscilloscope as follows.
Set horizontal deflection to 1 ms/division.
CH1 EXT
5.25-inch
TP~S
T?•12
3.5-inch
ZP SP
(2) Step between specified tracks at in the FLAG 0 item ofTable S.1 (Turn the seek delay switch on the exerciser to adjust 12
ms seek.)
(3) Loosen the track 0 sensor screw and adjust until the waveform on the oscilloscope appears as shown in Fig. 9.6.
A.DJ UST A.: B TO 1:1
Fig. 9.6 Track 0 Waveform
9.9 Limiter Verification (S~ts;;tnch)
(a.) Seek to track 00.
(b.) Push the carriage outward until it contacts the limiter, and r.ecalibrate.
Make sure that the carriage moves inward and returns to track 00.
(c.) If the carriage does not return to track 00 in Step (b), or if it contacts the limiter of the stepper motor, the stepper motor
assembly must be replaced because adjustment is useless.
9.10 Limiter Adjustment (3.5-inch)
(1) Seek to track 0.
(2) Write 2F data on track 0, and measure read level.
(3) Loosen the limiter mounting screw to free the limiter.
(4) Move the limiter until it just touches the head carriage on -1 track, and retighten the limiter mounting screw
securely.
(5) Check that, when the RE CAL switch on the exerciser is pushed ON, the head returns to track 0 and that the 2F
output level is the same as that measured in Step (2).
9.11 Asymmetry Verification
(1) Insert a work diskette.
(2) Step to the trac'- ~pecified in the symmetry item of Table 8.1.
(3) Set the oscilloscope as follows:
CH1
CH2
S.25·inch I TP•S
TP1
3.5-inch RD
T1
- 11 -

(4) Write 1 F.
(5) A read wave form is displayed on the oscilloscope as shown in Fig. 9.7.
(6) Confirm if it satisfies the value as shown in Fig. 8.1.
Fig. 9.7 Asymmetry Waveform
10. PANASONIC ALJGNMENT DISKETTE
Table 10.1. S.2.S.ihcfrAligl1mentDiske.tte
TPI
P/N
Index
Azimuth
Burst
34TRK 34TRK
48
8J7~l28
, ___
I
.....
-"-
68TRK 68TRK
96 817-560
68TRK 68RTRK
96 817-581
61TRK 61TRK
100 817-570
Table 10.2.
3.5 inch Alignment Diskette
TPI
PIN
Index
Azimuth
lurst
67.5 JU-01AA
20 20
40 40
135 JU-01AA
-12 -
Radial MODEL
16TRK JA-55X
JU-455
32TRK JA-56X
JU-465
32TRK JU-475
JU-58X
JU-59X
36TRK JU-570
Radial MODEL
20 JU-31 X
40 JU-32X
JU-36X

PART.II
11. REMOVALS AND INSTALLATIONS
11.1 PCB Removal and Installation (See Fig.11.1}
(1) Remove the two printed circuit board
mounting screws.
(2) Disconnect the connectors (J3 CON, J4 CON,
J6 CON, JS CON,J8CON) from the printed
circuit board.
(3) Remove the printed circuit board by sliding it
aslant.
(4) To reinstall, reverse the above procedure.
(5) Readjustment is not necessary after printed
circuit board replacement.
Fig.11.1 Printed Circuit Board Removal
White Line
I
~--
J3CON
Fig.11.1-1
Fig.11.1-2
Note:
Reverse connection prevention pin is not provided in J3 and J6.
When installing the P.C.B. board, connect them so that the white
line on the J3 connector is facing upwards and J6 connector pin
No. matches the P.C.B. side pin No.
- 13 -
11.2 Front Plate Removal and Installation
(See Fig.11.2)
(1) Operate the lock cam of the clamp assembly,
and turn the clamp handle in the direction of
clamping.
(2) Remove the clamp handle.
(3) Remove the two front plate mounting screws
and take off the front plate.
(4) Reverse the above procedure to reinstall.
Front Plate
Clamp Handle
Lock Cam
(Clamp Ass'y)
Fig. 11 .2 Front Plate Removal
11.3 Track 00 Assembly Removal and Installation
(See Fig. 11 .3)
( 1) Remove the track 00 assembly mounting
screw and take out the track 00 assembly.
(2) Pull out the white, yellow, and green wires
from J6 CON (1 OP).
(3) Reverse the above procedure to reinstall.
(4) After reinstallation, adjust the track 00 sensor
as described in 9.8.
Track '+'<il Assembly
Fig. 11.3 Track 00 Assemb!y Removal

11.4 Collet Assembly Removal, Installation, and
Adjustment (See Fig.11.4)
(1) Remove the Cartridge GuideAssembly as
described in 11.7
(2) Remove the lifter spring from the lifter.
(3) Remove the E-ring from the lifter shaft.
(4) Remove the lifter from the Cartridge Guide.
(5) Remove the Collet Assembly from the Guide
shaft.
(6) Reverse the above procedure to reinstall.
{7) After reinstallation, perform collet assembly
center adjustment.
(8) Collet assembly center adjustment.
a) Temporarily fasten the Cartridge Guide
Assembly.
b) Inserta diskette or dummy diskette and
clamp it.
c) Clamp repeatedly a few times to find a
good fit between the collet and the
inside diameter of the DD motor.
d) Bind the screw of the Cartridge Guide.
e) Check step c) again, if not good repeat
steps a) through d) until the correct
center adjustment is achieved.
ColletAssembly ---_ • ..
•
Fig. 11.4 ColletAssembly Removal
11.5 Clamp Assembly Removal and Installation
- 14 -
( 1) Remove the front plate as described in 11.2.
(2) Remove the two clamp assembly mounting
screws.
(3) Remove the clamp assembly.
(4) Reverse the above procedure to reinstall.
Clamp Assembly
Fig. 11.5 Clamp Assembly Removal

11.6 Write Protect Sensor/Index DetectorAssembly
Removal and Installation (See Fig. 11.6)
(1) Remove the front plate as described in 11 .2.
(2) Remove the write protectsensor mounting g
screw and index detector mounting screw
respectively.
(3) Remove the write protectsensor/index
detectorassembly.
(4)
Reverse the above procedure to reinstall.
(S) When reinstalling
the write protect sensor,
exercise care so that the leads and write
protectsensor will not projectfrom the
bottom and side of the base.
(6}
After indexdetector installation, adjust the
index timing as described in 9.7.
Fig. 11.6 Write Protect Sensor/Index Detector
Assembly Removal
11.7 Cartridge Guide Assembly Removal and
Installation (See Fig. 11.7)
- 15 -
(1)
(2)
(3)
(4)
(5)
(6)
(7)
Remove the printed circuit board as described
in 11.1.
Remove the front plate as described in 11.2.
Remove the shield plate mounting screw and
take the shield plate off.
Remove the write protectsensor as described
in 11 .6. It is not necessary to remove the
index detector.
Remove the four cartridge guide mounting
screws and take out the cartridge guide
assembly.
After reinstallation, adjust the collet assembly
as in 11.4step (6) and adjust the index timing
as in 9.7.
When removing or reinstalling, be careful not
to damage the carriage arm with the lifter.
Insulating Paper
~
ShieldPloto ~
~i
~
CartridgeGuide
Assembly
Fig. 11.7 Cartridge Guide Assembly Removal

11.8 Stepper Motor Assembly Removal and
Installation (See Fig. 11.8)
(1) Remove the insulating paper and shield
plate.
(2) Remove the track 00 sensor as described in
11.3.
(3) Remove the two (M2 x4) actuatorscrews that
fasten the actuator to the carriage arm
assembly.
(4) Remove the two (M3 x 6) stepper motor
assembly mounting screws and then the
stepper'motor.
(5) Reverse the above procedure to reinstall.
(6) After reinstallation, perfoim limiter check as
in 9.10 and radial alignment adjustment as in
9.5.
(7) Adjust the track 00 sensor according to the
instruction in 9.8.
Fig. 11.8 Stepper Motor Assembly Removal
- 16 -
11.9 carriage Arm Assembly Removal and
Installation (See Fig. 11.9)
(1) Remove the printed circuit board as described
in11.1.
(2) Remove the insulating paper and shield plate.
(3) Remove the track 00 assembly as described in
11.3.
(4) Remove the stepper motor assembly as
described in 11.8.
(5) Remove the two guide rod clamp mounting
screws.
(6) Remove the carriage arm assembly, guide
rod damp, and guide rod.
(7) Pull out the guide rod from the carriage arm
assembly.
(8) Reverse the above procedure to reinstall.
(9) After replacement, perform limiter
adjustment as described in 9.10, track 00
sensor adjustment as described in' 9.8, and
radial alignment adjustment as described in
9.5.
Fig. 11.9 Carriage Arm Assembly Removal

11.10 Drive Motor Removal and Installation
(See Fig. 11 .10)
(1) Remove the printed circuit board as
described in 11.1.
(2) Remove the insulating paper and shield
plate.
(3) Remove the front plate as described in 11.2.
(4) Remove the write protect sensor as described
in 11.6.
(5) Remove the cartridge guide assembly as
described in 11.7.
(6) Remove the three drive motor mounting
screws and take off the drive motor from the
base.
{7) Disconnect the drive motor connector pins
from the connector.
(8) Reverse the above procedure to reinstall.
(9) When reinstalling, make sure that the drive
motor connector is connected in the correct
direction.
(1 O)After reinstallation, perform motor speed
adjustment as described in 9.1 and also the
adjustments necessary upon reinstallation of
the cartridge guide as described in 11.7.
Drive Motor
Fig. 11.10 Drive Motor Removal
-17 -
11.11 LED Assembly Removal and Installation
(1) Remove the clamp handle and front plate.
(2) Disconnect the connectors J8 CON from the
printed circuit board.
(3) Remove the LED Assembly by sliding it aslant
from the Cartridge Guide Assembly.
(4) Reverse the above procedure to reinstall.
Fig.11.11 L~D Assembly Removal

12. TEST POINTS
Printed Circuit Board
(Top view)
GNO
TPS
V out (- ) V out ( +)
INTTRKes
TPS
TP6
+READ DATA
STEP
TP12
-18 -
TP7
+INDEX
TP10
GND