Panasonic JB-3300 Technical Manual page 360

4.1
4.2
OUTLINE OF MAINTENANCE
© The following tools are required for maintenance of a Floppy Disk Drive. (FDD)
Alignment Diskette
® Adjustments (Refer to table 8.1)
(1) Specify an applicable model from Tabel 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
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 1F or 2F (AII0's or 1's)
(4) Head load (5.25-inch FDD with optional head loader)
(5) Recalibration to track 00
The exerciser has switches and indicators to execute a specified function.
5. DIAGNOSTIC PROCEDURES
3.7
5.2
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 a drive
failure or maladjustment.
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 gooddrive.
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.
(2) Random electrical noise, normally a 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 controller side 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. Then return the head to the original track.
(3) Repeat Step (1).
(4) Any error that cannot be corrected by the above procedureis irrecoverable.