Apple Hard Drives Service Manual
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Service Source
Hard Drives
SCSI Drives
IDE Drives
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Service Source
Basics
Hard Drive
Basics IDE Drives - 1
IDE Drives
Intelligent drive electronics, IDE, incorporates controller
hardware into the drive. IDE is offered in 8- and 16-bit
interface types. Eight-bit drives are sometimes referred to
as XT interface drives, and 16-bit drives are sometimes
referred to as AT interface drives.
IDE drives do
to use an external SCSI chain, which is supported by a SCSI
chip on the logic board.
Also, Apple’s HD SC Setup works with IDE drives.
not
use a SCSI bus. Apple computers continue
Basics WIDE and FAST SCSI Protocols - 2
WIDE and FAST SCSI Protocols
SCSI chains that use SCSI-2 protocols are faster than SCSI
chains using the original SCSI protocols. Two terms used in
the SCSI-2 protocol are “WIDE” and “FAST.”
The term “WIDE” defines the 2-byte or 4-byte wide data
interface where each data byte uses its corresponding parity
bit. The traditional SCSI-1 interface protocol is 1 byte
wide. “FAST” SCSI is defined as data transfer rates between
5 MHz and 10 MHz.
Check these protocols against individual drives for
comparative data.
Devices using the SCSI-2 WIDE and FAST protocols are
compatible with existing SCSI-1 devices.
K
Service Source
Troubleshooting
Hard Drive
Troubleshooting General/ - 1
General
The Symptom Charts included in this chapter will help you
diagnose specific symptoms related to your product. Because cures
are listed on the charts in the order of most likely solution, try
the first cure first. Verify whether or not the product continues to
exhibit the symptom. If the symptom persists, try the next cure.
(Note: If you have replaced a module, reinstall the original module
before you proceed to the next cure.)
If you are not sure what the problem is, or if the Symptom Charts
do not resolve the problem, refer to the Flowchart for the product
family.
For additional assistance, contact Apple Technical Support.
Troubleshooting HD SC Setup/ - 2
HD SC Setup
Before you replace any drive hardware, run HD SC Setup to
update the driver on the drive.
HD SC Setup works with SCSI and IDE drives.
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Service Source
Upgrades
Hard Drives
Upgrades Drives in Quadra 900/950 - 1
Drives in Quadra
Hard Drive Carrier
Hard Drive Mechanism
900/950
SCSI Select
Cable
Termination
Resistors
SCSI Select
Switch
There are three general
procedures for preparing
hard drives for Quadra 900/
950 computers:
• Removing the hard drive
mechanism from the
carrier.
• Removing resistors
from the replacement
drives.
• Connecting the SCSI
select cable.
Upgrades Drives in Quadra 900/950 - 2
Removing the Hard Drive
1 Disconnect the SCSI
SCSI
Select
Cable
Drive Carrier
Hard Drive
select cable from the
hard drive.
2 Remove the four Phillips
screws.
3 Slide the drive out of the
carrier.
Upgrades Drives in Quadra 900/950 - 3
SCSI
Select
Cable
Tab
Terminator
Resistors
Tab
Removing Resistors from the 160 MB Hard Drive
Caution
the terminator resistors can
damage the logic board.
1 Pull up on the tab and
2 Insert the drive in the
3 Attach the SCSI select
: Failure to remove
remove the resistors
from a replacement
160 MB hard drive.
customer’s carrier and
install four screws.
cable tab-up as shown.
Upgrades Drives in Quadra 900/950 - 4
Hard Drive
Terminator
Resistors
SCSI Select
Cable
Tab
Removing Resistors from the 230 MB Hard Drive
Caution:
the terminator resistors can
damage the logic board.
1 Using needlenose pliers,
2 Insert the drive in the
3 Attach the SCSI select
Failure to remove
remove the resistors
from a replacement
230 MB drive.
customer’s carrier and
install four screws.
cable as shown.
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