3. TROUBLE ANALYSIS

3.1 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

CAUTION:
Be sure to switch power off before removing an FDD or PCB from the operating system.


3.1 TROUBLE ANALYSIS TABLE

Item 

Trouble 

No.

Cause 

JU-3X2, 252A, 253A

Index Detection Failure 1

 

1

DD motor control PCB

Replace DD motor assembly

2

DD motor faulty

Replace DD motor assembly

3

Index LED faulty

Replace
4 Index detector faulty Replace
5 PCB motor ON circuit Repair
6 PCB index detection circuit Repair
2 Not ready 1 See Item 1 Repair
2 PCB ready circuit  Repair
3 Track 0 detection failure 1 Track 00 assembly  Replace
2 PCB track 0 detection failure Repair
4 No seek 1 Stepper motor Replace
2 Guide shaft contamination or damaged Replace
3 PCB stepper driver circuit Repair
5 No WRITE 1 See Item 1  
2 Head disconnected  Replace
3 Head shorted  Replace
4 PCB write circuit  Repair
6 No READ  1 See Item 1  
2 See Item 5  
3 PCB read circuit Repair
7 READ ERROR 1 See Item 1   
2 See Item 6  
3 Alignment Adjust
4 Azimuth  Unadjustable
5 Burst Unadjustable
6 Asymmetry  
7 Limiter Adjust
8 Flag 0 Adjust
9 Index period Replace DD motor assembly
10 PCB read circuit Repair
8 IN USE LED won't light 1 LED part Replace
2 PCB IN USE circuit Repair
9 Write protect failure 1 Write protect part  Replace
    2 Write protect circuit Repair

 

4

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