The electrical and electronic components comprising the main chassis group, the
positioner assembly, and the power supply chassis
are
interconnected with the PCBAs
through use
of
interconnecting cable assemblies. The Read/Write
PCBA
is located
adjacent to the positioner assembly and the head cables connect directly
to
this board.
The
Read/Write PCBA is constrained
by
self-locking card guides. The Logic
PCBA
is
mounted on pivoting supports which
are
directly mounted to the
base
casting. Hinged
on
the face of the Logic
PCBA
is the Servo PCBA; these PCBAs are interconnected by
interboard flat cables.
4.2.5 TEMPERATURE
COMPENSATION PCBA
(200
TPI
MODELS)
The temperature compensation assembly, which is included
in
200
tpi models, is
comprised of a Temperature Compensation
PCBA
and a thermistor assembly. The
thermistor assembly is mounted
on
the positioner base plate.
4.3 FUNCTIONAL SUBSYSTEMS
The
major functional groups of the disk drive are illustrated in Figure 1-4; these major
groups, functionally discussed in the following paragraphs, are:
(1)
Positioner and Positioner Electronics
(2)
Read/Write Electronics
(3)
Disk Drive Function Control
(4)
Spindle Speed Control
(5)
Position Control Logic
(6)
Sector Electronics
(7)
Motor Control
(8)
Power Supply
(9)
Temperature Compensation
4.4 POSITIONER AND POSITIONER ELECTRONICS
An
essential function in a moving head disk drive is the positioning of the read/write
head
at the correct cylinder. This is accomplished in the· 03000 Disk Drive by
the·
Positioner
Servo ElectroniCS and the Positioner Assembly.
4.4.1
POSITIONER ASSEMBLY
The Positioner Coil and Moving Mass (linear motor), Velocity Transducer, and Position
Transducer are the three
mator functional entities which comprise the POSitioner
Assembly. Figure 4-2* shows the relationship
of
these subsystems to the Positioner Servo
Analog Circuits and the Positioner Control Logic.
The
linear motor consists
of
a stationary permanent magnet and a positioner coil attached
to the moving-mass, i.e., the carriage and magnetic
head
assembly. A description of the
physical arrangement of the Positioner is contained in Paragraph 4.2.2.
*Foldout drawing,
see
end
of
this section.
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