This manual explains the service procedures for the FUJITSU M255XK Family of
51" Mini Flexible Disk Drives.
This Section gives an overview of the Disk Drives.
Section 2 provides specifications.
Section 3 explains the drive's operations
Section 4 details maintenance procedures
Section 5 contains parts lists and mechanical and schematic drawings.
1.2 GEI\ERAL DESCRIPTION
M255XK disk drives offer superior performance, reliability and construction in
Flexible Disk Drive technology.
Industry standard 51" (130mm) diskettes are used as the storage medium.
drives have an independently addressed Read/Write head for each side of the
FM (Frequency Modulation) or MFM (Modified Frequency Modulation) recording
methods are acceptable.
There are three Models in the M255XK Family:
M2552K - This model records 5,922 flux transitions per il1ch and has a per disk
unformatted storage capacity of 1 Mbyte with MFM Encoding or 500
Kbytes with FM Encoding.
With a 16 sector format (256 bytes per sector), the M2552K emulates a
double density/double sided, 96 track per inch 51" industry standard
M255JK - This model records 9,646 flux transitions per inch and has a per disk
unformatted storage capacity of 1.604 Mbytes with MFM Encording or
802 Kbytes with FM'Encording.
With a 15 sector format (512 bytes per sector) the M2553K emulates a
double density/double sided, 96 track per inch (1.2 MByte) industry
standard 51" disk drive.
M2554K - This model has a host system controlled interface line (pin-2) that
allows operation at either 300 RPM, or 360 RPM.
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