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C141-E045-02EN 4 - 1
CHAPTER 4 THEORY OF DEVICE OPERATION
4.1 Outline
4.2 Subassemblies
4.3 Circuit Configuration
4.4 Power-on sequence
4.5 Self-calibration
4.6 Read/Write Circuit
4.7 Servo Control
This chapter explains basic design concepts of the disk drive. Also, this chapter explains
subassemblies of the disk drive, each sequence, servo control, and electrical circuit blocks.
4.1 Outline
This chapter consists of two parts. First part (Section 4.2) explains mechanical assemblies of
the disk drive. Second part (Sections 4.3 through 4.7) explains a servo information recorded
in the disk drive and drive control method.
4.2 Subassemblies
The disk drive consists of a disk enclosure (DE) and printed circuit assembly (PCA).
The DE contains all movable parts in the disk drive, including the disk, spindle, actuator,
read/write head, and air filter. For details, see Subsections 4.2.1 to 4.2.5.
The PCA contains the control circuits for the disk drive. The disk drive has one PCA. For
details, see Sections 4.3.
4.2.1 Disk
The DE contains the disks with an outer diameter of 95 mm. The MPB3021AT has 1 disk, the
MPB3032AT and MPB3043AT have 2 disks. MPB3052AT and MPB3064AT have 3 disks.
The head contacts the disk each time the disk rotation stops; the life of the disk is 40,000
contacts or more.
Servo data is recorded on each cylinder (total 60). Servo data written at factory is read out by
the read/write head. For servo data, see Section 4.7.