Panasonic JU-314 User manual

ORDER NO. MSD860605900
erviceManual
Flexible Disk Storage Drive
3.5 Inch
JU-314/JU-324/JU-364
Panasonic

CONTENTS
Page
PART 1
1. INTRODUCTION ············································· ·· ···················· ·· ··············································· ·· ··
2. MODELS AND MODEL NUMBERS ·· ·· ·········· ···· ··· ····· ..... ·· ... ·· ... ·· ····· ..····· ··· ·· ··· ·· · .... ·· ... ········· .... · ..... ··
3. SPECIAL TOOLS ·········.. ·················································..·····.. ········································· ·····..· ··
4. OUTLINE OF MAINTENANCE ···..· .... ·····.. ············..·····..·..···..·····..·······..····················..········..·····..·· 2
5. DIAGNOSTIC PROCEDURES · ··· ·· ··· ····· ······· ··· ·· ··· .... · ......... ···...·· ..... ········ ..... ··· ··· ·· .............. · .... .. ... ..... 2
5.1 Error Symptom Recognition ·········· ······· ··· ····· · ···· ·· ··· ····· ... ··..·····..····· ··· ·· ....... ·········· ..... · ····· ··· 2
5.2 Soft Error Detection and Correction ..······ .... ··..····· .... ···..····· .... ··· .... ···..····..···..··..·············..····· 2
5.3 Write Error ···· ·· ··· ··.. ···· .... ··· .... · ....···· · ..... ··.. ··· ..... · ..... ···· ..·· ··· ... ·· ····· ·· ··· ···. ··. · ··· ··..·· ...... ...... 2
5.4 Read Error · ..... · ....... ·· ····. ·· .... · ····· ........ ····..·.. ····· ..... ·..··.. ··· ······· ····· .. ··· ·· ······..·· ····· .... ·· ...... 3
5.5 Seek Error..................................................................................................................... 3
5.6 Interchangeability Error ·· ···· ... ····· ······· ··· ·· .... ·.. ···... · ............... ·····..· ··· ··· ······ ···· .. ··· .......... ·· ··.. 3
6. TROUBLE ANALYSIS ···..···········..···············..···· .... ···.. ·····..······ ·· ···..·················..·····..········ ············ 3
6.1 TroubleAnalysis Procedure ... ····· .. ·· ..·..· ......... ······· ... ···· ... ······· ......... ····································· 3
6.2 Trouble Shooting ........ ... .. ... ........................................ .... .......................................... ... .. 4
6.3 Trouble Analysis Table······· .. ········.············· .. ········ .. ············· ..··..·.. ······································ 5
7. PREVENTIVE MAINTENANCE· .................................................. ······························ .. ········ .... ·········.. 6
8. MEASUREMENT ITEMS FOR EACH MODEL ......... ............................................... .......... ...................... 6
9. ADJUSTMENTS AND VE RI FICA TIONS ·..···· .... ··· · ·· ..··· ...... ····························..······················ .... ·.. ·...... 7
9.1 Motor Speed Adjustment and Verification (Index Period) ··..···.. ···..·········· ...... ·..···..··..·· ..... ··..·· ... .. 7
9.2 Write ProtectVerification .. ........ .... ..... ....... ..... ....... ..... .. ........ ... .... ..... ... .... ..... ..... .. .... .. .... .... 7
9.3 Head Output Venf1cat1on ·.·· ·• .... ··· ... ··· ............. · ...... · .... · ... ······.·· .... ···..· ............ ·····..···..·..···· 7
9.4 Output Modulation Verification ········· ········· .... ···········.······· ······················ ..... ···.. ··· .... ··..······ 8
9.5 Radial Alignment Adjustment····· .. ···... ······· .. ···· ..·· ..... ·..·· ...... ········· .... ············· .. ··· ..·.. ······· ..·· 8-9
9.6 Azimuth Verification ..................................................................................................... ·· 10
9.7 Index Burst Verification ............ ····· ..... ······ .. ······· .. ········· ...· .... ·· ....... ····· ..... ·· ..... ··················· 10
9.8 Track 00 Sensor Adjustment ....... · ................. ·· .... · ........ ·· ............ · ........ · .... ····..······ .... ··· ...... ·· 11
9.9 LimiterAdjustment........................................................................................................... 11
9.10 AsymmetryVerification··· .................................................................................................. 11-12
10. PANASONIC ALIGNMENT DISKETTE ·· .... · .... · .... · ........... · ......... ···.. ·· ..······ .... ········..··· ... ·· .... ··· .... ·· ...... ·· 12
PART2
11. REMOVALS AND INSTALLATIONS
11.1 Removing and Remounting the Front Panel····· .. ····· ..·.. ······· .. ·················· ..·· .... · .... · ...... ···· ..··..·· 13
11.2 Removing and Remounting the HolderAssembly ............ ····· ..... ·· ... ·· ..... ·········· .... ·..................... 13
11.3 Removing and Remounting the head Assembly and Step Motor ............ ···· ...... · .... ··· .... ·.................. 13
11.4 Disassembly and Reassembly of the head Assembly and Step MotOF····.................. .......................... 14
11.5 Removing and Remounting the PCB ............................................................ ··.··.··· ..; ..... · ..... ·.· 15
11.6 Removing and Remounting the Disk DetectorAssembly ...... ·· ........ ······ ..................... ·· ····· ··· .... ···· 16
11.7 Removal and Remounting of the Track 0Sensor Assembly ............ ········ ..... ·· ........... ···.................. 16
12. TEST POINTS···: ....................................................................................................................... .
13. EXPLODED VIEW····.. ········ ..·· .. ····· .. ··· .. ···· .. ···· ..·.. ··················· ... ··············· ...... ····· ..·.. ····.... ············
14. REPLACEMENT PARTS LIST···· ... ······ .. ···· .... ··.. ·· ........ ··..·· ... ····· .. ··· .. ····· ....... ···· ........... ··· .... ··· .. ···· .. ·····
15. SCHEMATIC DIAGRAM OF CONTROL BOARD .................................................................................. ..
16. CIRCUIT BOARD ...............................................•....................•..................................•................
17
18-19
20-25
26-27
'28-29

PART. 1
1.INTRODUCTION
This service manual consists of two parts. Part 1 covers maintenance description,
adjustment procedures, and trouble analysis and Part 2 covers disassembly and
reassembly procedures, parts list, and PCB circuits.
Part 1 encompasses maintenance instructions for all FDD. Refer to the highlighted
applicable items, and perform maintenance work on the Floppy Disk Drive (FDD).
2. MODELS AND MODEL NUMBERS
2.1 3.5-inch FDD Series
3. SPECIAL TOOLS
The following special tools are used for FDD maintenance.
TABLE 3.1
Tool
Exerciser
Factry Alignment
Diskette
Data Diskette
CMOSfTTL Adaptor
Step Motor and Head
Assy Mounting Jig
Oscilloscope (SOMHz)
Probe (10: 1)
Frequency Counter
Note: *+-- : Standforthesameasleft.
- 1 -
Quantity
1-2
1-2

4. OUTLINE OF MAINTENANCE
• The following tools are required for maintenance of a Floppy Disk Drive.
4.1 Alignment Diskette
Alignment diskette is used for head actuator alignment and index sensor adjustment. Use the
right diskette as shown in Table 3. 1.
4.2 Exerciser
The exerciser enables you to make all adjustments and inspections necessary for an FDD. Its
functions include the following:
(1) Seek increment or alternate tracks
(2) Read (but no data compare)
(3) Write 1For2F(All O's or 1 's)
(4) 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 adrive failure.
Unless a visual inspection of the drive reveals an evident assembly fault or a defect, always
confirm errors with 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/write heads and diskette. This kind of contamination can be
easily eliminated by the liner in the diskette. Contaminated heads can be cleaned by a general
purpose non-abrasive head cleaning diskette. Please follow the suitable procedure provided
with the cleaning diskette.
(2) Random electrical noise, normallya few microseconds or less.
(3) Small defects in written data and/or track not detected during write operation may cause soft
errors during read.
(4) Faulty grounding of the drive or host system can also cause a soft error.
(5) Wrong motor speed is another cause of soft errors.
Take the following steps on the controllerside 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 track. 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.
5.3 Write Error
If an error occurs during write operation, it is usually detected during the next revolution by
performing a read operation called write check. To correct an error, write again and repeat a
write check operation. If the result is unsatisfactory after ten or more write operations, perform a
-2-

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 is faulty.
(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, check the track number on which the head
is located, and move the head away from it. And read it again.
5.6 Interchangeability Error
Data which is written by one drive may not be read by another. This error is called a Interchange-
ability error,which can be caused mostly by the following reason,which should be checked as
follows.
(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
(4) Format difference
6. TROUBLE ANALYSIS
6.1 Trouble Analysis Procedure
FDD trouble may occur in any of the following nine 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
Check with the troubleshooting flowchart in 6.2
CAUTION:
Be sure to switch power off before removing an FDD 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 and sectors
as far as the program permits.
Install Exerciser on FDD
Power SW
DC SW ON MOT SW ON
Drive Select SW
ON
YES
Media
Defective
Controller
Defective
Check Item 1,
Table 6.1.
Check Item 2,
Table 6.1.
Check Item 3,
Table 6.1.
- 4...,.
Write SW OFF
END
Check Item 4,
Table 6.1.
Check Item 5,
Table 6.1.
Check Item 6,
Table 6.1.
Check Item 7,
Table 6.1.
Check Item 8,
Table 6.1.
Check Item 9,
Table 6.1.

6.3 Trouble Analysis Table Table
6.1
Item Trouble No Cause
JU-3X2
Index detection
DD motor control PCB
Replace DD motor
failure
2
DD motor fault
assembly
3 Index LED fault
Replace
4 Index
detector fault
5 PCB motor ON circuit *
E-
6 PCB index detection circuit *
E-
2 Not ready
See Item 1.
2
PCB read circuit * E-
3 Track 0 1 Track 00 assembl *
E-
detection failure
2 PCB track 0 detection failure *
E-
4 No seek 1 Ste er
motor
* E-
2 Guide shaft contamination or dama *
E-
3 PCB ste er driver circuit *
.E-
5 No
WRITE
See Item 1.
2 Head disconnected *
E-
3 Head shorted *
E-
4 PCB write circuit *
E-
6 No
READ
See Item 1.
2
See Item 5.
3 PCB read circuit *
E-
7 READ ERROR
See Item 1.
2 See Item 6.
3 Ali nment
* E-
4
Azimuth
* E-
5 Burst Unad·ustable
6 As mmetr
7
Limiter
Ad-_
8
Fla
0 *
E-
9 Index period Replace
10 PCB read circuit *
E-
8
IN USE LED
1 LED art
* E-
won't light. 2
PCB IN USE circuit *
E-
9 Write protect
Write protect part
Replace
failure
2 Write rotect circuit *
E-
Note: * E-: Stand for the same as left.
-5 -

7. PREVENTIVE MAINTENANCE
8.
No preventive maintenance is necessary for any type of FDDs under normal conditions of use.
However if it is determined that adjustments are necessary, the following must be done.
• Adjustments (Refer to table 8.1)
(1) Specifyan applicable model from Table 8.1, and make a read/write head radial adjustment
at a specified track.
(Sides 0, 1)
(2) Make an index timing adjustment at a specified track. (Sides 0, 1)
(3) Make an azimuth measurement at a specified track. (Sides 0, 1)
CAUTION
Do not write when using alignment diskette. Check that write protect sensor is properly
operating with a data diskette.
Note :Section 9 describes the adjustment procedures in detail.
MEASUREMENT ITEMS FOR EACH MODEL
Table 8.1
JU-384
Item Parameter
TRK Value
Index period 40 166.6
ms
± 1%
2 Output level
79 160mV
more than
3 Radial 40
50%,
Alignment
±25µm
4
Azimuth
40 ± 18'
5 Index burst 40
2.5 ±
0.85 ms
6 Flag 0 From track 1:1
1 to track 2
and back
7 Limiter - 1 Recalibrate
and return
too
8 Asymmetry
79 <350 ns
* Value
of Item 3, 4, 5: only DAD (Dynamic Alignment Diskette) typ.
-6-

9. ADJUSTMENTS AND VERIFICATIONS
9.1 Motor Speed Adjustment and Confirmation (Index Period)
(1) Inserta 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.
IX (INDEX)
(4) Check that the frequency counter readings meet the specifications in the table.
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 hole open ON
Media with write protect hole closed : OFF
9.3 Head Output Verification
Use a new diskette if possible to identify head failure for this check
(1) Inserta 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.
CH1 Tl
CH2 T2
EXT IX (Index)
Invert channel 2 and select the Add mode.
Setvertical 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 FDD, 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.
M(%) =Vmax - Vm~n x 100 using the value obtained in 9.3, and check that the calculated
Vmax + Vmm value is 20% or less. .
---------rr- .... E:;;:::~== .. ~-::::z---=:--- Maximum vo1tage vaiue: vmax
Average Voltage
Minimum Voltage Value: Vmin
__________ ___,1---1--1-~
----------~~---
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) below 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) Insertan alignment diskette.
CAUTION:
Be sure to leave the alignment diskette underroom conditions for 20 minutes before
adjustment.
(2) Step to the track specified in the Radial alignmentcolumn of Table 8. 1.
(3) Leave the oscilloscope in the same condition as mentioned in section 9.3.
• Cats Eye System
(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 RIA 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 amplitude, 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 B
Ax 100
B>A A
8 x 100
Fig. 9.2 Radial Alignment Waveforms (CATS EYE)
Note: Alignments on sides 0 and 1 are adjusted at the factory. If they are misaligned, adjust them to
meet the specifications of Table 8.1.
• DAD (Dynamic Alignment Diskette)
(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 B4 in Fig. 9.3, and calculate the lobe ratio from
the following formulas.
~A> ~B: x 100% ~A< ~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 completed.
(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 on the instrument.
Index
burst
waveform
Azimuth
waveforms
L~
r
A,
8,
j
-
r-H
In
u
20ms
Radial alignment waveforms '
e,
B,
A.
A, s.
A,
70msJ
._,_,
-
120m.J
170ms
Fig. 9.3 Alignment Waveform (DAD)
-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.
A
..
..
..
..
..
..
..
..
..
..
B C
Azimuth O' waveforms
9.7 Index Burst Verification
B
c D
A
Case of B>C
Azimuth =: = ~ x (A)
(A) : CE-30'
DAD-15'
Fig. 9.4 Azimuth Waveforms
c
A B
D
CaseofC>B
Azimuth = ~ =! x (A)
(1) Insert an alignment diskette. Seek to the track specified in the l/B column of Table 8.1.
(2) Set the oscilloscope time base as follows:
1ms/division
(3) Check that the time from oscilloscope start to the first data pulse meets the l/B specifications
of Table 8. 1. (DAD system)
(4) If the specifications are not met, No adjustment necessary for 3.5-inch models.
~I
I
Index Burst
Fig. 9.5 Index Timing
- 10 -

9.8 Track 00 Sensor Adjustment
(1) Set the oscilloscope as follows.
Set horizontal deflection to 1ms/division.
CH1 ZP
EXT SP
(1) Step between specified tracks at in the FLAG 0 item of Table 8.1 (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. 9.9.
t
A
5V
----------{----------
B
----------=----! GND
ADJUST A:B TO 1:1
Fig. 9.86 Track 0 Waveform
9.9 limiter Adjustment
( 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 - 1track, and retighten the limiter
mounting screw securely.
(5) Check that, when the RECAL switch on the exerciser is pushed ON, the head returns to track
Oand that the 2F output level is the same as that measured in Step (2).
9.10 Asymmetry Verification
(1) lnsertadatadiskette.
(2) Step to the trackspecified in the symmetry item of Table 8.1.
(3) Set the oscilloscope as follows:
CH1 RD
CH2 T1
(4) Write 1 F.
(5) A read wave form is displayed on the oscilloscope as shown in Fig. 9.7.
(6) Confirm ifit satisfies the value as shown in Table 8.1.
- 11 -

Fig. 9.7 Asymmetry Waveform
10. PANASONIC ALIGNMENT DISKETTE
Table 10.1
TPI
PIN
135 817-384
3.5 inch Alignment Diskette
Index
Burst
40TRK
-12 -
Azimuth
40TRK
Radial
Alignment
40TRK
MODEL
JU-38X

PART. 2
11. DISASSEMBLY AND REASSEMBLY
11.1 Removing and Remounting the Front
Panel
(1) Remove the two cover fastening screws
and remove the cover.
(2) Remove the two front-panel fastening
screws and remove the front panel.
(3) Remount them in the reverse order of the
above.
Cover
Front Panel
Fig.11.1 Removing the Front Panel
11.2 Removing and Remounting the Holder
Assembly
(1) Remove the front panel following the
procedure in paragraph 11. 1.
(2) Remove each lever fastening screw and
remove the two levers.
(3) Lift the holder assembly by hand so that
the edge of the holder assembly does not
touch the lever assembly as shown in
figure 11-2 and remove it by sliding it
toward the front side. In this case, lift the
side 1 of the head assembly by the thumb,
otherwise it strikes side 0 due to the head
retaining spring on the side 1 when it
drops from the holder.
(4) Remount it in the reverse order of the
above.
(5) Check the operation of the holder
assembly after it has been remounted.
(6) Operation check of the holder assembly
a) When mounting the two levers,
temporarily fasten the fastening
screws.
b) Slide in and out the media several
times and confirm that the movement
is smooth.
c) After properly tightening the two
screws, reconfirm that the movement
is smooth.
Head Assemb~ly (Side 1) Lever
~ Lever Assembly
. "
~. Lever
~
HolderAssembly
Fig. 11.2 Removing the HolderAssembly
11.3 Removing and Remounting the head
Assembly and Step Motor
- 13 -
{1} Remove the holder assembly following the
procedure in paragraph 11.2.
(2) Push up and remove the FPC clamp using
such as tweezers.
(3) Pull up the FPC contact part inserted into
the head connector J3 by picking it up with
such as flat pens so as not to damage it.
(4) Remove the step motor cable connector
from the J4 connector on the PCB.
Fig.11.3
~FPCCl•mp
I
FPC Contact Part
Removing the Head Assembly and
Step Moter
(5) Remove the set screw on the right-side
clamp and remove the right-side clamp.

(6) Remove the set screw on the left-side
clamp and remove the left-side clamp.
(7) Remove the set screw on the clamp end
and remove the clamp end.
(8) Draw out the long and short shafts.
Left Side Clamp
~i
~
Short Shaft
Right Side Clamp
i
'1--Clamp End
,' ~
/LoogSh•ft
Fig. 11.4 Removing the Head Assembly
(9) Remove the two fastening on the step
motor and remove the step motor by
holding it by hand together with the head
assembly.
Step Motor
Cable Connector
Fig. 11.5 Removing the Step Motor
(lO)Remount them following the reverse
procedure of the above steps (1) to (9).
When remounting the right-side clamp in
step (5). remount it while pushing it in the
arrow direction shown in figure 11-6.
When remounting the right-side left-side
clamps, replace them with new ones.
Right Side Clamp
0
When remounting the right side clamp push it
toward the right by the width of the play.
Fig. 11.6 Remounting the Right-Side Clamp
(1 l)After mounting the above, adjust the head
alignment according to paragraph 9.5,
adjust the track 00 sensor according to
paragraph 9.8, and adjust the limiter
according to paragraph 9. 10.
11.4 Disassembly and Reassembly of the head
Assembly and Step Motor
- 14 -
Disassembly
(1) Mount the head assembly and step motor
on a fitting jig as shown in figure 11-7 and
remove the steel-belt fastening screw on
the step-motor capstan and the same on
the carriage section.
Fig. 11.7 Removing the Steel Belt
Reassembly
(1) Mount the step motor and head on the jig
as shown in figure 11-8 and 11-9.
(2) Wind a new steel belt in the shape of alpha
as shown in figure 11-9.

I
~
Fig. 11.8 Remounting the Step Motor
(3) Set the hook A of the steel belt to the
carriage tab.
(4) Set the ring of the steel belt wound in the
shape of alpha to the capstan.
(5) Insert the guide rod into the head
carriage.
(6) Puli out the hook B of the steei belt with
tweezers and set it to the tab on the jig.
Set the tension handle in the arrow
direction.
Hooked Portions
Fig. 11.9 Mounting the Steel Belt
(7) Retighten the capstan fastening screws
and carriage section fastening screws. In
this case check if the steel belt is bent or
distorted and also alignment.
(8) Return the tension handle to the original
position and unhook the steel belt.
(9) Check the smooth operation of the
carriage by moving it back and forth.
(10) Pull out the guide rod.
Fig. 11.10 Operation of the Tension Handle
(1 l)Cut the hook B with a nipper.
11.5 Removing and Remounting the PCB
- 15 -
(1) Remove each two screws on the right-side
and left-side brackets and remove the
right-side and left-side brackets.
(2) Remove connectors J3, J4, and JS, J6 from
the PCB.
(3) Remove the two fastening screws on the
PCB and remove the PCB.
~ I
i i
I I
' i
Fig. 11.11 Removing the PCB

(4) Remount it following the reverse order of
steps ( 1) to (3).
Treat the JS cable as shown in figure 11-12
when remounting the PCB. Set the PCB
beneath the base as shown in the figure.
JS Cable
lower the control
package side
Fig.11.12 Mountingg the PCB
11.6 Removing and Remounting the Disk
DetectorAssembly
(1) Remove the holderassembly following the
procedure in paragraph 2.
(2) Remove the right-side and left-side
brackets.
(3) Remove the disk detectorcable connector
from the J3 terminal.
(4) Remove the disk detector fastening screws
and remove disk detector.
(5) Remount it following the reverse order of
steps (1) to (4).
Fig. 11.13 Removing the Disk Detector
Assembly
11.7 Removal and Remounting of the Track 0
Sensor Assembly
(1) Remove the cover
-16 -
(2) Remove the cable connector from the J6
terminal.
(3) Remove the track sensor assembly
fastening screws and remove the track
sensor assembly.
(4) Remount it following the reverse order of
steps (1) to (3).
(5) Adjust the track 00 sensor according to the
procedure in paragraph 9.8 after
remounting it.
Fig.11.14 Removing the Track OSensor
Assembly

V out(+)
T1
V out(-)
T2
TRKO
ZP
(Sensor out for adjustment)
READY
......
RY
I
SIDE SELECT
SS
+INDEX .
IX
STEP
SP
WO
WRITE
DATA
0
+READ DATA GROUND
AG
WRITE
WG
WP
DIRECTION
10
MOTORON
MO
DRIVE SELECT
OS
NC
...ai
N
•
---1
m
V\
---1
-a
0
·-
z
---1

,13. EXPLODED VIEW-1
'-·~.1
8
·8
-18 -