Apple External Hard Drive Sc Service Manual

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Service Source

External Hard Drive SC

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Service Source

Exploded V ie w

External Hard Drive SC

Exploded View 1

Exploded View

Cover

HDA-to-Case Cable

LED Cable Assembly

Hard Drive Mechanism

Fan Frame

Fan

SCSI Select Switch

SCSI Select Switch Cable

Power Supply

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Service Source

T ak e Apart

External Hard Drive SC

Take Apart Cover - 1

Cover

No preliminary steps are
required before you begin
this procedure.

Cover

Note:

This Take Apart
chapter applies only to the
Apple external hard drive
series (20SC, 40SC, 80SC,
or 160SC). For Take Apart
procedures internal drives,
see the manual for the
computer that contains the
drive.

Take Apart Cover - 2

1 Locate the two holding

tabs on the rear of the
hard drive, inside the
ventilation slots.

2 Using a jeweler’s

screwdriver, press in
gently on the two
holding tabs as you push
the cover up slightly.

Take Apart Cover - 3

3 Locate the four tab holes,

two on each side of the
hard drive.

4 Starting with the rear

holes, insert the
jeweler’s screwdriver
straight into each of the
holes. Nudge the cover
upward as you release
each tab.

Note:

Prying is not
necessary and may damage
the case.

Take Apart Power Supply - 4

Power Supply

Before you begin, remove
the cover.

Power Supply

Caution:

precautions in Bulletins/
Safety.

Review the ESD

Take Apart Power Supply - 5

1 Press down on the back

of the power supply,
push back the power
supply tab, and lift the
power supply.

Take Apart Power Supply - 6

2 Disconnect the power

supply connector from
the hard drive
mechanism.

Power Supply

Note:

On some hard

Fan

Cable

drive mechanisms, the
power supply connector
is on the opposite side of
the hard drive.

3 Disconnect the fan cable.

4 Lift the power supply

free.

Power Supply

Connector

Take Apart Hard Drive Mechanism - 7

Hard Drive Mechanism

Before you begin, remove
the cover.

Hard Drive
Mechanism

Caution:

precautions in Bulletins/
Safety.

Review the ESD

Take Apart Hard Drive Mechanism - 8

1 Push back the large tab,

slide the hard drive
mechanism up, and rest
it on the edge of the case.

Tab

Hard Drive
Mechanism

Take Apart Hard Drive Mechanism - 9

2 Disconnect the power

supply.

Note:

SCSI Select
Switch Connector

On some hard
drive mechanisms, the
power supply connector
is located on the
opposite side of the hard
drive.

3 Open the end tabs (if

present) on the hard
drive data cable
connector and disconnect

Power
Supply

Connector

HDA-to-Case
Cable

Hard Drive Mechanism

the cable from the hard
drive mechanism.

Take Apart Hard Drive Mechanism - 10

4 Disconnect the SCSI

select switch connector
and lift the hard drive
mechanism out of the
case.

Note:

Skip the following
steps if you are replacing a
20 MB or a 160 MB
external hard drive. Return
these drives to Apple in
their original carriers.

Take Apart Hard Drive Mechanism - 11

Note:

Four screws hold the

5.25-inch hard drive along
the bottom edge of the

LED Cable

SCSI Select
Switch

carrier.

5 Turn the drive over and

remove the four screws
near the center of the
metal carrier. Use this
carrier to install the
service replacement
module.

6 Disconnect the LED

cable and SCSI select
switch from the hard
drive mechanism.

Edge of 3.5 Drive

Take Apart Hard Drive Mechanism - 12

Note:

Review “Carrier
Removal,” “Modifying 5.25
Drives,” or “Modifying 3.5
Drives” in Additional
Procedures before you
install the new service
replacement drive.

Take Apart SCSI Select Switch Cable - 13

SCSI Select Switch Cable

Before you begin, remove
the following:

SCSI Select
Switch

• Cover

• Hard drive mechanism

Caution:

precautions in Bulletins/
Safety.

Review the ESD

Take Apart SCSI Select Switch Cable - 14

Slide the cable out of the
holding clamps attached to
the carrier.

Holding Clamps

Take Apart LED Cable Assembly - 15

LED Cable Assembly

Before you begin, remove

LED Cable Assembly

the following:

• Cover

• Hard drive mechanism

Caution:

precautions in Bulletins/
Safety.

1 If you are repairing a

Review the ESD

hard drive160SC,
remove the four screws
and pull the end bracket
and the LED cable from
the hard drive.

Take Apart LED Cable Assembly - 16

2 Using a jeweler’s

screwdriver, pry the

Retaining Ring

small plastic retaining
ring from around the
LED holder. Slide the
ring up the wires and out
of the way.

3 Press the face of the LED

toward the inside of the
metal carrier until the
LED snaps free of the
plastic holder.

4 Remove the LED cable

assembly.

Take Apart Fan Frame - 17

Fan Frame

Before you begin, remove
the cover.

Fan Frame

Caution:

precautions in Bulletins/
Safety.

Note:

disconnect the power supply
when you remove the hard
drive mechanism for this
procedure.

Review the ESD

It is not necessary to

Take Apart Fan Frame - 18

Using a flat-blade
screwdriver, push back the
plastic tab and lift out the
metal fan frame (with fan,
HDA-to-case cable, fan
cable, and SCSI select switch
attached).

Plastic Tab

Take Apart HDA-to-Case Cable - 19

HDA-to-Case Cable

Before you begin, remove

HDA-to-Case
Cable

the following:

• Cover

• Fan frame

Caution:

precautions in Bulletins/
Safety.

Review the ESD

Take Apart HDA-to-Case Cable - 20

1 Remove the four screws

that hold the HDA-to­case cable to the frame.

2 Lift the cable free.

Fan Frame

Take Apart Fan - 21

Fan

Before you begin, remove
the following:

• Cover

• Fan frame

• HDA-to-case cable

Fan

Caution:

precautions in Bulletins/
Safety.

Review the ESD

Take Apart Fan - 22

1 Remove the two screws

that hold the fan to the
frame.

2 Lift the fan free.

Fan Frame

Take Apart SCSI Select Switch - 23

SCSI Select Switch

Before you begin, remove
the following:

SCSI Select
Switch

• Cover

• Fan frame

Caution:

precautions in Bulletins/
Safety.

Review the ESD

Take Apart SCSI Select Switch - 24

Push the switch through the
fan frame. Depress the two
plastic tabs—first on one
side and then the other.

Fan Frame

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Service Source

Additional Procedures

External Hard Drive SC

Additional Procedures Carrier Removal - 1

Carrier Removal

No preliminary steps are
required before you begin
this procedure.

Note:

This procedure
applies to hard drive
mechanisms that have been
removed from a computer or
an external hard drive, or to
replacement drive
mechanisms that have not
yet been installed in the
computer.

Additional Procedures Carrier Removal - 2

Drive
Carrier

Hard
Drive

Caution:

Review the ESD
precautions in Bulletins/
Safety.

Remove the four screws and
lift the carrier from the
hard drive.

Replacement Caution:

Be
sure to properly torque the
replacement drive to its
carrier. Failure to do so
could damage the drive. See
“Torque Sequence” in this
chapter.

Additional Procedures Carrier Removal - 3

Note:

For return
information on defective
drives, see “General Return
Info” in this chapter and
refer to the Service Source
parts database Note of the
drive you are returning.

Additional Procedures Torque Sequence - 4

Torque Sequence

No preliminary steps are
required before you begin
this procedure.

Note:

This procedure
applies to hard drive
mechanisms that have been
removed from a computer or
an external hard drive, or to
replacement drive
mechanisms that have not
yet been installed in the
computer.

Additional Procedures Torque Sequence - 5

Using a torque driver,
tighten the screws in the
order shown. Torque the
screws to 8.0-inch pounds.

Torque Driver

Drive Carrier

Note:

The torque sequence is
the same for all types of
drives and carriers.

Hard Drive

Additional Procedures Modifying 5.25 Drives - 6

External Hard Drives Only

Modifying 5.25 Drives

No preliminary steps are
required before you begin
this procedure.

Note:

This section describes
procedures for modifying

5.25-inch replacement
hard drives that are
qualified for external hard
drives. To learn whether a
replacement drive is a
qualified external drive,
refer to compatibility
information in the Service

Additional Procedures Modifying 5.25 Drives - 7

Source parts database Note
for the drive.

Note:

The 20 MB and160
MB external 5.25-inch
replacement hard drives

Customer’s
External
Carrier

ship prepared for external
drives. You must modify
other replacement hard
drives for use in external
hard drives.

1 Remove the four

mounting screws and
carrier from the 5.25­inch service
replacement hard drive.

Power Cable

Additional Procedures Modifying 5.25 Drives - 8

2 Disconnect the power

cable (if attached) from

Termination

Resistors

the replacement drive.

3 Disconnect the

termination resistors
from the component side
of the service
replacement drive. Use
needlenose pliers and

SCSI Select Cable

Jumpers

pull the resistors
straight up.

Replacement Note:

Be
sure that the tab on the
SCSI select cable
connector points toward
the hard drive data cable.

Additional Procedures Modifying 5.25 Drives - 9

4 Connect the SCSI select

cable to the three pairs

Customer’s

External Carrier

of pins on the component
side of the replacement
drive. Leave the black
jumpers on the other
pins.

5 Connect the LED cable

connector from the

LED

customer’s external
carrier to the component
side of the replacement
drive.

Additional Procedures Modifying 5.25 Drives - 10

6 Attach the reconfigured

replacement hard drive
in the customer’s
external carrier with
the four screws.

Note:

For return
information on defective
drives, see “General Return
Info” in this chapter and
refer to the Service Source
parts database Note of the
drive you are returning.

Additional Procedures Modifying 3.5 Drives - 11

External Drives Only

Modifying 3.5 Drives

No preliminary steps are
required before you begin
this procedure.

Note:

This section describes
procedures for modifying

3.5-inch replacement hard
drives that are qualified for
external hard drives. To
learn whether a replacement
drive is a qualified external
drive, refer to compatibility
information in the Service
Source parts database Note
for the drive.

Additional Procedures Modifying 3.5 Drives - 12

Note:

The External 20MB
SCSI, Rev A replacement
hard drive ships prepared

Power Cable

Termination Resistors

for use in external hard
drives. You must modify
other replacement hard
drives for use in external
hard drives.

1 Remove the 3.5-inch

replacement hard drive
from its carrier.

2 Disconnect the power

cable (if attached) from
the replacement drive.

Note:

The location of the
termination resistors
may differ.

Additional Procedures Modifying 3.5 Drives - 13

3 Disconnect the three

termination resistors
from the component side
of the replacement drive.
Use needlenose pliers, if
necessary.

Important:

the customer’s SCSI select
cable to six unkeyed pins on
the controller board. Be
aware that SCSI select cable
connectors differ in both
design and location among
drives.

You must connect

Additional Procedures Modifying 3.5 Drives - 14

4 For SCSI select cable

connectors located on
the edge of the drive

Tab

SCSI
Select Cable

controller board:

• Remove any black

jumpers that may be
installed on the
outside pins.

• Face the tab up and

attach the SCSI cable
connector.

Additional Procedures Modifying 3.5 Drives - 15

5 For SCSI select cable

SCSI
Select
Cable

Tab

connectors located on
the surface of the
controller board:

• Face the SCSI cable

connector tab toward
the center of the drive.

• Attach the connector

to the six pins closest
to the 50-pin SCSI
connector.

Additional Procedures Modifying 3.5 Drives - 16

Important:

SCSI select connectors and
cables vary. To verify the
proper position of the SCSI
select cable connector,
connect the drive to a
known-good Macintosh and
choose Get Info from the
Finder’s File menu. If Get
Info displays the wrong
SCSI ID or drive name,
reverse the tab of the SCSI
select cable connector.

Combinations of

Additional Procedures Modifying 3.5 Drives - 17

Customer's
External Carrier

LED

6 Connect the LED cable

connector from the
customer’s external
carrier to the component
side of the replacement
drive.

7 Install the reconfigured

replacement hard drive
in the customer’s
external carrier.

Note:

For return
information on defective
drives, see “General Return
Info” in this chapter and
refer to the Service Source
Parts database Note of the
drive you are returning.

Additional Procedures General Return Info - 18

General Return Info

No preliminary steps are
required before you begin
this procedure.

Note:

You must return a
defective hard drive to Apple
with the correct
combination of carrier and
cables.

Additional Procedures General Return Info - 19

Return defective hard drives
in one of three carrier
combinations:

• Switch the hard drive

carriers.

• Return the drive without

a carrier.

• Return the drive with the

carrier from the
customer’s unit.

Note:

For specific return
requirements, refer to the
Service Source Parts
database Note of the drive
you are returning.

Additional Procedures General Return Info - 20

Each drive has four cables
that may or may not need to
be returned:

LED Cable

SCSI Select Cable

• Power cable

• Hard drive data cable

Hard Drive

Data Cable

• SCSI select switch cable

• LED cable

Note:

For specific return
requirements, refer to the
Service Source parts
database Note of the drive
you are returning.

Power Cable

Additional Procedures Setting SCSI ID - 21

Setting SCSI ID

No preliminary steps are

SCSI Select Pins

required before you begin
this procedure.

To set the SCSI ID, locate the
drive’s six SCSI select pins.

Note:

If you are installing
the drive in a docking
station, such as the
DuoDock, Apple
recommends you change the
SCSI ID to 1. If you are
installing the drive
mechanism in an external
drive case, Apple

Additional Procedures Setting SCSI ID - 22

recommends you change the
SCSI ID to any number from
2 to 6.

Note:

The location of the
SCSI select pins varies
among drives. Generally, the
group of six (occasionally
eight) pins is on the top or
side of the printed circuit
board.

Place jumpers on the pairs
of pins as shown in the table
below.

Additional Procedures Setting SCSI ID - 23

Note:

In the following table, the SCSI ID numbers are
labeled across the top and the pin numbers are labeled on the
side. (The pin pairs may be labeled using either the A0-A1­A2 pin number convention or the E1-E2-E3 convention.
Some pin pairs may not be labeled.) The letter “J” indicates
a jumper.

01234567

A0/E1 - J - J - J - J

A0/E2 - - J J - - J J

A0/E3 ----JJJJ