Read Error; Seek Error; Interchangeability Error; Trouble Analysis - Panasonic JU-475-4 Service Manual

5.4

Read Error

Most read errors are soft errors. Data can be recovered by fo llo w in g the recovery procedure in
section 5.2.
5.5

Seek Error

Seek errors are caused by the follow ing.
(1) Stepper m otor or stepper m otor drive circuit is faulty.
(2) Faulty Carriage
There are tw o 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 w hich is w ritte n by one FDD may n ot be read by a n o th e r.
interchangeability error, which can be caused mostly by the follo w in g reasons, which should be
checked as follows.
(1) Head misalignment: Refer to Adjustments and Confirm ation section 9.6.
(2) Head o utp ut too low: Refer to Confirm ation section 9.3.
(3) M otor speed difference: Refer to Adjustments and Confirm ation section 9.1.
(4) Format incom patibility.

6. TROUBLE ANALYSIS

To determine the cause o f trouble w hether it lies in the FDD, diskette, or controller, replace the
diskette and the FDD w ith good ones.
procedure below.
6.1

Trouble Analysis Procedure

FDD trouble may occur in any o f the fo llo w in g ten forms.
(1) Index detection failure
(2) I/O 34pin signal failure (Disk Change/R eady/M edia In /M e d ia Out)
(3) Track 0 undetectable
(4) No seek
(5) No w rite
(6) No read
(7) Read error
(8) IN USE LED w o n 't light.
(9) W rite protect undetectable
(10) No head load (5.25inch FDD w ith optional head loader)
Check w ith the troubleshooting flo w ch art in section 6.2.
CAUTION:
Be sure to switch the power o ff before removing an FDD or PCB from the operating system.
If the FDD is assumed fa u lty as a result, fo llo w the
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This e rro r is called a