Diskette Inserted Detection; Head Load Mechanism; Door Lock Mechanism; Circuit Operations - Fujitsu M255XK Customer Engineering Manual

3.1.9 Diskette Inserted Detection
The diskette inserted mechanism detects the presence or absence of a diskette in
the disk drive.
The diskette inserted detector is comprised of an LED and photo transistor
assembly (photo-interrupter). This photo-interrupter provides a signal to the
drive's circuitry whenever a diskette is inserted into the drive.
3.1.10 Head Load Mechanism
The head load mechanism extends the service life of the read/write heads and
diskettes by allowing them to come into uniform contact with each other, only
when necessary.
The head load mechanism is comprised of the head load solenoid, arm lifter
assembly, and associated parts.
3.1.11 Door Lock Mechanism
The door lock mechanism locks the front lever during all read or write operations
to prevent the door from being opened, and causing damage or the lost of data.
The door lock mechanism is comprised of the door lock solenoid, eject assembly,
and associated parts.
3.2 CIRCUIT CPERATIONS
The drive's electronic circuitry is comprised of three major sections:
Read/Write Circuits - explained in paragraph 3.2.1.
Control Circuits - explained in paragraph 3.2.2.
Spindle Motor Servo Circuits - explained in paragraph 3.2.3.
The Read/Write, and Control circuits are mounted on the main circuit board and
the Servo circuits are mounted on the spindle motor board.
3.2.1 Read/Write Circuits
The Read/Write circuits include read circuits, write circuits, low voltage detection
circuits, and associated sections. These various sections are accommodated in one
LSI control circuit. A partial diagram of this LSI control circuit is shown in
Figure 3-3.
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