panasonic JU-475 5inch floppy diskette drive.pdf

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ORDER NO. MSD891122000
ervice Manual
Flexible Disk Storage Drive
JU-475-4
Panasonic
CONTENTS
PART I
Page
1
1
1
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1.
2.
INTRODUCTION .••..•..•••.•.•••..•..••••••.••••.•••••.••.••••..••••••••••••••••••••••••••••••••••
MODELS AND MODEL NUMBERS
2.1
5.25inch FDD Series
3.
4.
SPECIAL TOOLS •••.•••.••••••••••.•••.•••••••••••••.•••••.••••••••••••.•••••••••.•••••••••••.•••••
OUTLINE OF MAINTENANCE •.••.••••••.•••••••••••.•.•..••••••.•.•••••••••••••••...••.••.•.••.•••.•
1
2
2
4.1
4.2
Alignment Diskette
Exerciser
Error Symptom Recognition
Soft Error Detection and Correction
Write Error
Read Error
Seek Error
Interchangeability Error
Trouble Analysis Procedure
Troubleshooting Flow Chart
Trouble Analysis Table
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2
2
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2
5.
DIAGNOSTIC PROCEDURES .•••••••.••..••••••••••.••••••••.••.••.•••••••••••.••••••••••••••••.•••.•
5.1
5.2
5.3
5.4
5.5
5.6
2
6.
TROUBLE ANALYSIS •••.•••••.••••..•.•.•••••••••••..••.••.••.••...••••..••••••••••.•••••••••.•••••
6.1
6.2
6.3
3
3
3
3
3
4
5
6
6
7.
PREVENTIVE MAINTENANCE
SPECIFICATIONS
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8.
9.
ADJUSTMENTS AND VERIFICATIONS ••..••.•.•••.•••..•.••••.•••••••••.•...•••••••••.•••.•••••••••.•
7
7
9.1
9.2
9.3
9.4
9.5
9.6
9.7
9.8
9.9
9.10
Motor Speed Verification (Index Period)
Write Protect Verification
Head Output Verification
Output Modulation Verification
Resolution Verification
Radial Alignment Verification and Adjustment
Azimuth Verification
Track 0 Sensor Adjustment
Asymmetry Verification
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Index Burst Verification and Adjustment
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7
7
8
8
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9
10
10
11
10.
11.
TEST POINTS ••.••..••••••••..••••..•••.••.•.••••••••••..•.•.••••••••••••••••.•.••.•.••••••••.••••.
PANASONIC ALIGNMENT DISKETTE .••..••••••••••••••.••••..••••••.••.••..•.•.••.••.•••••••••••••••
12
13
PART"
12.
REMOVALS AND INSTALLATIONS ••.••..••••••••••••••••••.••••••.••••••••••••••••••.••..•••.•.•••••
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14
15
15
16
16
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18
18- 19
20
21
21
12.1
12.2
12.3
12.4
12.5
12.6
12.7
12.8
12.9
12.10
12.11
12.12
12.13
12.14
PCB Removal and Installation
Front Plate and Handle Removal and Installation
Track 0 Sensor Removal and Installation
Collet Assembly Removal, Installation, and Adjustment
Clamp Assembly Removal and Installation
Write Protect Sensor Assembly and Index Sensor Assembly Removal and Installation
Cartridge Guide Assembly Removal and Installation
Stepper Motor Assembly Removal and Installation
Head Carriage Assembly Removal and Installation
Drive Motor Removal and Installation
LED Assembly Removal and Installation
Lifter Unit Removal and Installation
Media Lifter Removal and InstaHation _
Media Sensor Assembly Removal and Installation
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13.
14.
15.
16.
EXPLODED VIEW •..•...................••..•..•.•••.•••.•.••••••.••••....••••••••••••••.••••.•••••
REPLACEMENT PARTS LIST .•.••••...••..••.•••••••••..••••.••.••••..•••••••••••••••••.•••••••.•••••
REPLACEMENT PARTS LIST FOR PCB •.•.•••••.••••...••.•••••••.••.••.•••••.•••.••.••.•••••••••••••.•
SCHEMATIC DIAGRAM
BLOCK DIAGRAM
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CIRCUIT BOARD .••.•..•..••••.•••..•.•.•.••.•••••.•.•.•••.•.••..•••••.••..••••••.•••••••••••.••••.
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17.
18.
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-1-
PART. I
1. INTRODUCTION
This service manual consists of two parts, Part I covers maintenance description, adjustment
procedures, and trouble analysis and Part II covers disassembly and reassembly procedures, parts
list, and PCB circuits.
Part I encompasses maintenance instructions for all Floppy Disk Drive (FOO) models. Refer to the
highlighted applicable items, and perform maintenance work on the FOD.
Note:
This service manuals is prepared for maintenance of the FOO.
Do not use this manual for judging pass or fail criteria in inspections.
2.
2.1
MODELS AND MODEL NUMBERS
5.25inch FDD Series
Itlill
48TPI
-c
JA-551
JU-455
96TPI
JA-56X
JU-58X
.
JU-595
JU-465
-c
-c
JA-560
JA-561
JU-581
JU-585
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3.
SPECIAL TOOLS
The following special tools are used for FDO maintenance.
Table
3 - 1
Special Tools
Part No.
Tool
5.25 inch (48TPI)
JA-551/ JU-455
Exerciser
Alignment diskette
Data diskette
Oscilloscope (50 MHz)
Probe(10: 1)
Frequency counter
Note:
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JA-561/ JU-465
817-560
2DO
Quantity
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1-2
1-2
FOD-EXT-35
817-128
2D
3
Stand for the same as left.
-1 -
4.
•
OUTLINE OF MAINTENANCE
The following tools are required for maintenance of an FDD.
4.1
Alignment Diskette
Alignment diskette is used for head actuator alignment and index sensor adjustment.
Use the right diskette as shown in Table 8.1.
4.2
Exerciser
The exerciser enables you to make all adjustments and inspections necessary for an FDD.
functions include the following.
(1) Seek increment or alternate tracks
(2) Read (but no data compare)
(3) Write 1For2F(AII "O"sor"1"s)
(4) Head load (5.25inch FDD with optional head loader)
(5) Recalibration to track 0
The exerciser has switches and indicators to execute a specified function.
Its
5.
5.1
DIAGNOSTIC PROCEDURES
Error Symptom Recognition
Errors that occur because of the wrong operating procedure, wrong programming, the use of a
defective diskette, or soft errors due to external causes, such as contaminated air and random
electrical noise, are often attributed to an FDD failure.
Unless a visual inspection of the FDD reveals an evident assembly fault or a defect, always confirm
errors with another good diskette, and another known good FDD.
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. Please follow the appropriate procedures
provided with the cleaning diskette.
Random electrical noise, normally a few microseconds or less.
Small defects in written data and/or track not detected during write operation may cause
soft errors during read.
Faulty grounding of the FDD or host system can also cause soft errors.
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.
Read the track again ten times or until the data is recovered.
If step (1) above fails to recover the data, access the adjacent track. Then return the head to
the original track.
Repeat step (1).
Any error that cannot be corrected by the above procedure is irrecoverable.
(2)
(3)
(4)
(5)
(1)
(2)
(3)
(4)
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
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, assume the FDD defective. If the error is corrected, the diskette is
defective. It can be thrown away.
- 2-
5.4
Read Error
Most read errors are soft errors. Data can be recovered by following the recovery procedure in
section 5.2.
5.5
Seek Error
Seek errors are caused by the following.
(1)
(2)
Stepper motor or stepper motor drive circuit is faulty.
Faulty Carriage
There are two ways to recover from a seek error. One is to recalibrate to track 0, 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. Read it again.
5.6
Interchangeability Error
Data which is written by one FDD may not be read by another. This error is called a
interchangeability error, which can be caused mostly by the following reasons, which should be
checked as follows.
(1)
(2)
(3)
(4)
Head misalignment: Refer to Adjustments and Confirmation section 9.6.
Head output too low: Refer to Confirmation section 9.3.
Motor speed difference: Refer to Adjustments and Confirmation section 9.1.
Format incompatibility.
6. TROUBLE ANALYSIS
To determine the cause of trouble whether it lies in the FDD, diskette, or controller, replace the
diskette and the FDD 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)
(2)
(3)
(4)
(5)
(6)
(7)
(8)
(9)
(10)
Index detection failure
I/O 34pin signal failure (Disk Change / Ready / Media In / Media Out)
Track 0 undetectable
No seek
No write
No read
Read error
IN USE LED won't light.
Write protect undetectable
No head load (S.2Sinch FDD with optional head loader)
Check with the troubleshooting flowchart in section 6.2.
CAUTION:
Be sure to switch the power off before removing an FDD or PCB from the operating system.
- 3-

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