HP 7942 Service Manual page 9

Recording Medium . . . . . . . . . . . . .
Read/Wri te Heads . . . . . . . . . . . . .
Read Preamplifier/Write Driver IC
Servo Head ........ .
Servo Preamplifier IC .
Spindle Moto r ...... .
Air Filtration Components
Actuator Lock Driver .
Spindle Speed Control
Spindle Speed Checker
Spindle Motor Brake Relay and Relay Driver
Actuator Servo Control
Demodu la to r ..... .
Mode Select Switch
Seek
~Iode
Velocity DAC
Tachometer .,
Slclpe Selector
Current Inverter
On-Peak Detector
Power Amplifier
Inverter ..... .
Track--Follow Mode .
Off-Track Detector
Seek Operation
Restore to Track 0 Operation
Read/Wri t.e Data Channel .....
Head SelE!ct and Control Logic .
Read Chain . . . . . . . . . . . . .
Ampli f ier/Signal Condi tioner ..
Differential Line Driver
Wri te Chain ........ .
Line Receiver .... .
Transition Generator
Write Current Source
Write Fault Detector
Sel f test ...... .
Power Supph' A4
AC Input Circuits
Swi tch-Mc)de Supply
Power-On Reset ....
Section IV
SERVICE INI4'ORMATION
Introduction
Service Tools
FRA Locations
CONTENTS (continued)
3-15
3-16
3-16
3-16
3-17
3-17
3-17
3-17
3-17
3-17
3-17
3-17
3-18
3-18
3-18
3-18
3-18
3-19
3-19
3-19
3~19
3-19
3-19
3-19
3-19
3-19
3-20
3-20
3-20
3-20
3-20
3-20
3-20
3-20
3-21
3-21
3-21
3-21
3-21
3-22
3-22
Page
4-1
4-1
4-2
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