Product manual

Spinpoint M9TU-USB 3.0 Product Manual REV 1.0
14
INSTALLATION
CHAPTER 5 DISK DRIVE OPERATION
This chapter describes the operation of the Spinpoint M9TU-USB 3.0 hard disk drive functional subsystems.
It is intended as a guide to the operation of the drive, rather than a detailed theory of operation.
5.1 Head / Disk Assembly (HDA)
The Spinpoint M9TU-USB 3.0 hard disk drive consists of a mechanical sub-assembly and a printed circuit
board assembly (PCBA), as shown in Figure 5-1. This section describes the mechanism of the drive.
The head / disk assembly (HDA) contains the mechanical sub-assemblies of the drive, which are sealed
between the aluminum-alloy base and cover. The HDA consists of the base casting assembly (which
includes the DC spindle motor assembly), the disk stack assembly, the head
stack assembly, and the rotary
voice coil motor assembly (which includes the actuator latch assembly). The HDA is assembled in a clean
room. These subassemblies cannot be adjusted or field repaired.
CAUTION: To avoid contamination in the HDA, never remove or adjust its cover
and seals. Disassembling the HDA voids your warranty.
The Spinpoint M9TU-USB 3.0 hard disk drive models and capacities are distinguished by the number of
heads and disks. The ST750LM023 have three (3) disks and six (6) read/write heads. The ST1000LM025 has
two (2) disks and four (4) read/write heads.
5.1.1 Base Casting Assembly
A one piece, aluminum-alloy base casting provides a mounting surface for the drive mechanism and PCBA.
The base casting also serves as the flange for the DC spindle motor assembly. A gasket provides a seal
between the base and cover that enclose the drive mechanism.
5.1.2 DC Spindle Motor Assembly
The DC spindle motor assembly consists of the brush-less three-phase motor, spindle bearing (FDB)
assembly, disk mounting hub, and a labyrinth seal. The entire spindle motor assembly is completely
enclosed in the HDA and integrated to the base casting. The labyrinth seal prevents bearing lubricant from
coming out into the HDA.
5.1.3 Disk Stack Assembly
The disk stack assembly in the Spinpoint M9TU-USB 3.0 hard disk drive consists of 3 disks and disk spacers
secured on the hub of the spindle motor assembly by a disk clamp. The glass disks have a sputtered thin-film
magnetic coat
ing.
5.1.4 Head Stack Assembly
The head stack assembly consists of an E-block/coil sub-assembly, read/write heads, a flexible circuit, and
bearings. The E-block/coil sub-assembly is assembled with an E-block and bonded coil. Read/write heads
are mounted to spring-stainless steel flexures that are then swage mounted onto the E-block arms.
The flexible circuit connects the read/write heads with the PCBA via a connector through the base casting.
The flexible circuit contains a read/write Preamplifier IC.