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 following the recovery procedure in
section 5.2.
5.5 Seek Error
Seek errors are caused by the following.
(1) Stepper motor or stepper motor drive circuit is faulty.
(2) 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) Head misalignment: Refer to Adjustments and Confirmation section 9.6.
(2) Head output too low: Refer to Confirmation section 9.3.
(3) Motor speed difference: Refer to Adjustments and Confirmation section 9.1.
(4) 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) Index detection failure
(2) I/O 34pin signal failure (Disk Change / Ready / Media In / Media Out)
(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 (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.
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