Apple iMac DV Special Edition Service Manual

K

Service Source

iMac, iMac DV, iMac DV

Special Edition

Updated 11 July 2005

K

Service Source

Basics

iMac, iMac DV, iMac DV Special

Edition

Basics Overview - 1

Overview

Product Description

A completely new iMac,
redesigned from top to
bottom, inside and out—and
available in three new
models: iMac, iMac DV, and
iMac DV Special Edition.

The computer offers several
new, unique features,
including translucent
plastics, wireless-ready
networking technology, a
VGA port that provides

Basics Overview - 2

mirrored RGB out, FireWire ports, and digital video
technology to name a few

Basics New Technologies - 3

New Technologies

AirPort Wir eless Networking

The iMac, iMac DV, and iMac DV Special Edition computers
support wireless networking using the optional AirPort
wireless networking card. To participate in wireless
networking, the system must have the following:

• internal antenna - The antenna necessary for wireless
networking is already installed inside the iMac computer.

• AirPort Card - This small card (about the size and shape
of a credit card) can be installed in the wireless
networking slot inside the computer. Users can purchase
cards from an Apple-authorized dealer or from The Apple
Store.

Basics New Technologies - 4

In addition, to access another computer network or Internet
service provider, users need to connect a wireless access
device to their network. This access can be an AirPort Base
Station (a stand-alone hardware product with a wireless
antenna and network/modem connections) or an AirPort
Software Base Station (software running on a wireless­equipped computer).

FireWire

FireWire is a high-speed data system that lets you easily
connect and disconnect external devices—such as digital
video (DV) cameras, printers, scanners, and hard disks
without restarting your computer. The better and best iMac
configurations include two external FireWire ports on the
side panel.

Basics New Technologies - 5

VGA Output Port

The iMac DV and iMac DV Special Edition computer includes a
port for an external video monitor, so you can mirror, or
show, what’s on the computer display to a larger audience.
The external monitor supports only the display sizes that
are available on the internal monitor.

The connector for the video monitor is a three-row HD15
connector (DB9/15, also called mini sub D15) for use with
a VGA, SVGA, or XGA monitor.

Basics Features - 6

Features

Processor

There are three shipping configurations: iMac (good), iMac
DV (better), and iMac DV Special Edition (best).

• 350-MHz (good) or 400-MHz (better/best) Power PC
G3 processor

• 100-MHz system and memory bus

• 512K L2 cache

Basics Features - 7

Memory

• 64 MB SDRAM (good/better), 128 MB SDRAM (best) of
PC-100 SDRAM (168-pin, running at 100 MHz

• two DIMM slots support up to 512 MB of PC-100 SDRAM
DIMMS

Storage

• one of the following hard drives:

– 6 GB EIDE (good)
– 10 GB EIDE (better)
– 13 GB EIDE (best)

• one of the following optical drives:

– 24x-speed, slot-load ATAPI CD-ROM drive (good)
– 4x-speed, slot-load, ATAPI DVD-ROM drive

(better/best)

Basics Features - 8

Graphics Support

• ATI RAGE 128 VR 4x 2D and 3D acceleration

• 8 MB video
millions of colors

• 15-pin VGA connector for mirrored RGB out port
(better/best)

SGRAM, which supports 3D features and

Communication

• 11 MB wireless-ready (antenna in enclosure)
technology

• 56K V.90 modem and Group 3 Fax send/receive
compatible

Basics Features - 9

I/O

• one 10/100 Mbps Ethernet RJ-45 connector for
connection to either a 10Base-T or 100Base-TX hub
networks

• two external USB ports, 12 Mbps per port

• two FireWire ports, 6-pin 400 Mbps (better/best)

Sound

• two built-in stereo speakers, internal microphone, dual
headphone jacks, analog audio in/out line level jacks

• digital audio, spatializer N-2-2, AC-3 Playback, bass
enhancement

Basics Features - 1 0

iMac Models Comparison

CPU Speed

• Original iMac: 233 MHz

• Rev-B iMac:

• 5-color iMacs:

• iMac, iMac DV, iMac DV Special Edition: 350 MHz (good)
or 400 MHz (better and best models)

L2 Cache

• Original iMac: 117 MHz

• Rev-B iMac:

• 5-color iMacs:

• iMac, iMac DV, iMac DV Special Edition: 40 or 160 MHz

233 MHz

266 MHz or 333 MHz

133 MHz

133 MHz

Basics Features - 1 1

System Bus Speed

• Original iMac: 66 MHz

• Rev-B iMac:66 MHz

• 5-color iMacs:

• iMac, iMac DV, iMac DV Special Edition: 100 MHz

66 MHz

Main Memory

• Original iMac: 32 MB up to 128 MB

• Rev-B iMac: 32 MB up to 128 MB

• 5-color iMacs: 32 MB up to 128 MB

• iMac, iMac DV, iMac DV Special Edition: 64 MB up to 512
MB

Basics Features - 1 2

Graphics Controller Chip

• Original iMac: ATI RAGE IIc

• Rev-B iMac: ATI RAGE Pro

• 5-color iMacs: ATI RAGE Pro Turbo

• iMac, iMac DV, iMac DV Special Edition: ATI RAGE 128
Pro 4x

Graphics Memory

• Original iMac: 2 MB, expandable

• Rev-B iMac: 6 MB

• 5-color iMacs: 6 MB

• iMac, iMac DV, iMac DV Special Edition: 8 MB

Basics Features - 1 3

Hard Disk Drive

• Original iMac: 4 GB

• Rev-B iMac: 4 GB

• 5-color iMacs: 6 GB

• iMac, iMac DV, iMac DV Special Edition: 6 GB (iMac), 10
GB (iMac DV) or 13 GB (iMac DV Special Edition)

CD Drive

• Original iMac: Tray-loaded CD-ROM

• Rev-B iMac: Tray-loaded CD-ROM

• 5-color iMacs: Tray-loaded CD-ROM

• iMac, iMac DV, iMac DV Special Edition: Slot-loaded CD­ROM or DVD-ROM

Basics Features - 1 4

Data Ports

• Original iMac: USB

• Rev-B iMac: USB

• 5-color iMacs: USB

• iMac, iMac DV, iMac DV Special Edition: USB; optional
FireWire

Communication Features

• Original iMac: 56K modem, infrared port

• Rev-B iMac: 56K modem, infrared port

• 5-color iMacs: 56K modem

• iMac, iMac DV, iMac DV Special Edition: 56K modem;
optional wireless-ready AirPort Card

Video Mirroring

• iMac, iMac DV, iMac DV Special Edition: HD-15
connector for VGA output (iMac DV and iMac DV Special
Edition)

Basics Views - 1 5

Vi e w s

Front, Side, and Rear View

Basics Views - 1 6

I/O Panel with FireWire

Basics Views - 1 7

I/O Panel without FireWire

Basics Views - 1 8

iMac Logic Board

Basics Repair Strategy/Warranty - 19

Repair Strategy/Warranty

Strategy and Ordering

The iMac (350 MHz), iMac DV, and iMac DV Special Edition
includes a 1-year complimentary carry-in warranty.
Service the computer through module exchange and parts
replacement. Customers can request on-site service from an
Apple-Authorized Service Provider Plus (AASP+) Apple
Assurance (US only), or Apple Canada Technical Answerline
(Cananda only).

Apple-service providers planning to support the computer
systems covered in this manual may purchase Service
modules and parts to develop servicing capability. To order
parts, use the AppleOrder (U.S. only) or ARIS (Canada only)
system and refer to the iMac Slot Load CD/DVD Service
Price Pages.

Basics Repair Strategy/Warranty - 20

Large businesses, universities, and K-12 accounts must
provide a purchase order on all transactions, including
orders placed through the AppleOrder (U.S. only) or ARIS
(Canada only) system.

USA Ordering

U.S. Service providers not enrolled in AppleOrder may fax
their orders to Service Provider Support (512-908-

8125) or mail them to

Apple Computer, Inc.
Service Provider Support
MS 212-SPS
2323 Ridgepoint Drive
Austin, TX 78754

Basics Repair Strategy/Warranty - 21

For U.S. inquiries, please call Service Provider Support
(800-919-2775, option 1).

Canadian Ordering

Canadian service providers not enrolled in ARIS may fax
their orders to Service Provider Support in Canada (800­903-5284). For Canadian inquiries, please call Service
Provider Support (800-217-9517).

Warranty

US Only

The iMac, iMac DV, and iMac DV Special Edition computers
are covered under the Apple One-Year Limited Warranty.
The AppleCare Service Plan is also available for these
products. Service Providers are reimbursed for warranty

Basics Repair Strategy/Warranty - 22

and AppleCare repairs. For pricing information, refer to
Service Price Pages.

Canada Only

The iMac, iMac DV, and iMac DV Special Edition computers
are covered under AppleCare. The Extended AppleCare
Service Plan is also available for these products. Service
Providers are reimbursed for warranty and AppleCare
repairs. For pricing information, refer to Service Price
Pages.

K

Service Source

Specifications

iMac, iMac DV, iMac DV Special

Edition

Specifications Introduction - 1

Introduction

Specifications information for this product can be found in the Spec Database, which you can
access at Service Source Online (http://service.info.apple.com) or on Service Source CD.

Spec Database at Service Source Online

From the Service Source Online home page, click Troubleshoot and Repair to access the main
repair procedures page. Then click either Apple Spec in the navigation table in the upper
right corner of the page, or click Apple Spec Database from the list of reference tools below.

Spec Database on Service Source CD

Open the CD and double-click the Apple Spec Database alias located at the top level of the CD.

K

Service Source

Troubleshooting

iMac, iMac DV, iMac DV

Special Edition

Troubleshooting Introduction - 1

Introduction

This chapter contains basic theory of operations information as
well as detailed Symptom/Cure tables, both of which should help
you troubleshoot and repair the iMac, iMac DV and iMac DV
Special Edition systems.

The Symptom/Cure tables are broken down into two sections:
problems that can occur at startup time-before the Finder
appears on the screen; and problems that can occur after a
successful startup. Each major symptom has its own symptom/
cure table.

In the left-hand column of each table are the possible causes of the
symptom, with the corresponding cures in the right-hand column.
You should also follow the tables in the order presented as they
represent the most logical order for cause and cure. Verify
whether or not the product continues to exhibit the symptom. If
the symptom persists, try the next cure. (
replaced a module, reinstall the original module before you
proceed to the next fix.)

: If you have

Note

For additional assistance, contact Apple Technical Support.

Troubleshooting Block Diagram - 2

Block Diagram

The following illustration provides an overview of the iMac inter­nal components and shows how they are connected.

System Block Diagram

Hard

Drive

CD-ROM

Drive

Modem

AirPort/

Adapter

Card

EMI Cover

Digital Electronics

Main

Logic

Board

Power Supply

Down Converter

Analog Electronics

Video

Neck

Board

Power Supply and

Video Deflection Board

Speakers,

Headphone Jacks,

Microphone,

Power/Led Board

Yo k e

CRT

Troubleshooting Power Flow/ - 3

Power Flow

Power is controlled in the iMac system by the power/analog
board. Once the unit is plugged in, power flows from the AC outlet
at the wall to the AC inlet on the power/analog board. From there,
the power flows through the main cable on the power/analog
board, to the video neck board, down converter board, logic board,
and all its attached components.

Troubleshooting Testing for Power - 4

Testing for Power

The iMac requires trickle voltage (+5 TRKL) in order to power­on. If you are experiencing power problems in the iMac unit, you
will want to test for trickle power to pinpoint the location of the
problem and to determine whether or not the power supply/analog
board is functioning normally. If you have trickle power in the
system, the odds are your power/analog board is OK.

In general, you should test for power at the AC outlet first. Next, it
is best to check the logic board. In this way, you will be able to
immediately pinpoint which module is failing.

The following procedures will explain how to test for power at the
AC outlet and at the logic board.

At the AC Outlet

If the unit will not power up from the keyboard, first, unplug the
keyboard from the computer. Then, using a known-good power
cord, power-on the system using the power button on the front of
the computer. If the system powers on, you can assume the AC out­let is good and the problem is with the keyboard. If the system still
won’t power on, try connecting to a different AC outlet. If the unit
powers on this time, you most likely have a problem with the AC
outlet. If you still have no power, you may need to reset the PMU
chip (power manager) on the logic board (refer to “Resetting the
Logic Board” in this chapter).

Troubleshooting Testing for Power - 5

At the Logic Board

With the iMac placed with the CRT face down on a soft surface,
remove the bottom housing and the EMI cover to access the logic
board.

Testing J9 for +5 V Trickle Power on the Logic Board

You will need a volt meter to test for power on the logic board.
Refer to the picture on the next page to locate the necessary test
point referenced in the following procedure.

Plug in the computer, but leave the iMac powered OFF. Ground the
black probe on the volt meter to the logic board screw, as shown in
the photograph below. With one hand behind your back, touch the
red probe on the volt meter to the top pad (pin 1) at J9 (see the
photograph below) on the logic board, to see if you have +5V on
the logic board. A +5V reading on the logic board means the power
supply is providing the necessary trickle voltage to the logic
board.

Testing for +5 V Trickle Power at J9 on the Logic Board

Troubleshooting Testing for Power - 6

Testing DCO (Down Converter On) Voltage at C10 on the Logic
Board

In a No Power situation, first check for +5 V trickle power at J9
(refer to “Testing J9 for +5 V Trickle Power on the Logic
Board”), then check the DCO (Down Converter On) voltage on the
logic board at capacitor C10 (see figure below).

The DCO voltage should be present as soon as the power cord is
plugged into the computer. Ground the black probe on the volt
meter to the logic board screw, as shown in the photograph below.
Touch the red probe to C10 (see the photograph below.) The DCO
voltage should measure approximately -1.2 volts with the power
cord plug plugged in. The voltage will jump to 21 volts after pow­ering on the system. A reading of -1.2 volts up to +1 volt indi­cates the logic board is OK. Without a reading of -1.2 volts, verify
the fuse at F901 is OK (refer to “Testing the Power/Analog Board
Fuse” in this section). If the fuse is OK replace the power/analog/
video board.

Testing DCO Voltages at C10 on the Logic Board

Troubleshooting Testing for Power - 7

Testing J7 for Voltage on the Logic Board

The following voltages measure if the down converter is providing
the required voltages and are only present if the system is pow­ered on. If the following voltages are not correct, refer to the “No
Power” troubleshooting symptom chart.

Measure the following voltages at J7 on the logic board:

1. Pin 2: +12 volts

2. Pin 4: +5 volts

3. Pin 14: +3.3 volts

Testing Voltages at J7 on the Logic Board

Troubleshooting Testing for Power - 8

Testing the Power/Analog Board Fuse

First remove the bottom housing, front outer bezel, and the top
rear housing to access the power/analog board. The fuse is located
near the AC plug.
Warning: You must unplug the iMac to do a continuity test at the
power supply board fuse.

You will need an ohm meter to do a continuity test on the power
supply board fuse. Refer to the picture below to located the neces­sary test point referenced in the following procedure.

Unplug the computer to take this reading. Using an ohm meter,
touch the red and black probes to the two metal points at location
F901 and check for continuity (reading of “0”). If the ohm meter
registers “0”, the fuse is good. If the meter registers “infinite”,
the power/analog/video board should be replaced. A bad fuse is
indicative to a power/analog/video board problem.
this reading, it’s easiest to insert the red probe of the meter
through the opening on the back side panel.

Note:

To take

Testing Fuse 901 for Continuity

Troubleshooting The PMU Chip - 9

The PMU Chip

The PMU (Power Management Unit) is a microcontroller chip that
controls all power functions for the computer. The PMU is a
computer within a computer. It has memory, software, firmware,
I/O, two crystals, and a CPU. Its function is to:

• Tell the computer to turn on, turn off, sleep, wake, idle, etc.

• Manage system resets from various commands.

• Maintain parameter RAM (PRAM).

• Manage the real-time clock.

Important:

Remove the battery when handling the logic board so the PMU is
not affected. The PMU is
on the logic board can cause the PMU to crash. If the PMU crashes,
the battery life goes from about five years to about two days if the
PMU is not reset. Refer to the next topic, “Resetting the PMU on
the Logic Board” for the procedure. Many system problems can be
resolved by resetting the PMU chip. The PMU reset button is
located on the right side of the board, refer to the logic board dia­gram below.

Be

careful when handling the main logic board.

very

sensitive and touching the circuitry

very

iMac (350 MHz) Logic Board Diagram

Troubleshooting Resetting the PMU on the Logic Board - 10

Resetting the PMU on the Logic Board

Resetting the PMU (Power Management Unit) on the logic board
can resolve many system problems. Whenever you have a unit that
fails to power up, you should follow this procedure before
replacing any modules.

1. Disconnect the power cord and check the battery in the bat­tery holder (BT1). The battery should read 3.3 to 3.7 volts.
If the battery is bad, replace the battery, wait ten seconds,
and then reset the PMU (refer to the next step). If the bat­tery is good, go to the next step.

2. Press the PMU reset switch (S1) once on the logic board and
then proceed to step 3. Do
second time because it could crash the PMU chip.

3. WAIT ten seconds before connecting the power cord and pow­ering the computer on. If the computer powers on, go to the
next step. If the computer does not power on, there is some­thing else wrong with the computer, refer to the symptom/
cure chart, “No Power” in this chapter.

press the PMU reset switch a

NOT

4. Run MacTest Pro and return the computer to the customer.

This entire procedure resets the computer’s PRAM. Be sure

Note:

to reset the computer’s time, date and other system parameter
settings before returning the computer to the customer.

Troubleshooting Power-On Self Test - 1 1

Power-On Self Test

There is a power-on self test that resides in the ROM of the iMac.
This test automatically runs whenever the iMac is powered on
after being fully shut down (the power-on self test does not run if
the machine is only restarted).

If a problem is detected during the test, you will not hear a
normal startup chime. Instead, the system will beep as explained
below. Refer to “Error Beeps” later in this chapter for
instructions on how to troubleshoot and repair an iMac that sounds
error beeps at startup time.

Following is a definition of what the error beeps at startup time
signify.

One Beep:

Two Beeps:

ships with PC-100 SDRAM and does not accept SDRAM SO­DIMMs or EDO memory).

Three Beeps:

Four or Five Beeps:

boot ROM. The ROM (which is located on the processor module)
is bad.

No RAM is installed or detected.

Incompatible memory is installed. (The iMac

No RAM banks passed memory testing.

Bad checksum for the remainder of the

iMac



Verifying a Defective Power/Analog/Video
Board

Many of the power/analog/video boards returned to Apple as “bad” or “DOA” have no
trouble found at the repair facility. It is important to verify a defective power/analog/video
board properly before ordering a replacement. Follow the steps below to verify if the issue
is due to a bad power/analog/video board or if something else is causing the problem.

Products affected

• iMac (Slot Loading)

• iMac (Summer 2000)

• iMac (Early 2001)

• iMac (Summer 2001)

Procedure

1. Check for bent pins on the CRT neck (see Figure 1). Remove the video board and
observe the pins on the CRT neck. Make sure all of them are straight. If the pins are
not straight, carefully attempt to straighten them with a flatblade jeweler’s screwdriver
or needlenose pliers and test the board again.

Figure 1 CRT Neck Pins

073-0593 Rev. A

2. Make sure the video board is properly seated on the CRT neck (see Figure 2). The top
picture shows the video board improperly seated; the bottom picture shows it properly
seated. When the video board is properly seated, the plastic socket of the video board
slides up to the retaining ring on the CRT neck, just before the CRT neck rings.

critical

to function properly.

that the video board be fully seated in order for the power/analog/video board

It is

Figure 2 Video Board Improperly and Properly Seated

Verifying a Defective Power/Analog/Video Board -

2

3. Check the connection of the RGB cable to the logic board. (see Figure 3).

Figure 3 RGB Cable Connection

4. Remove the RGB cable and inspect the pins on the logic board connector (see Figure

4). If the pins are bent, carefully attempt to straighten them with a flatblade jeweler’s
screwdriver or needlenose pliers and test the board again.
connector are very fragile. If they become damaged, you will need to replace the logic
board.

Figure 4 Main Logic Board Connector Pins

Note:

The pins on this

Verifying a Defective Power/Analog/Video Board -

3

Troubleshooting Power Button - 12

Power Button

The power button on the front of the iMac (see Table 1 below) will
power up the computer, or put it to sleep, but it will not shut the
iMac down.
pulses on and off.

The power button on the keyboard (see Table 2 below) retains
previous functionality. The keyboard button can power up the
iMac, put the iMac to sleep, or shut down the computer with a
press of the button. And, as before, you can shut down the com­puter by selecting Shut Down in the Special menu.

Table 1: iMac Power On Button Functionality

When the iMac is in Sleep mode, the amber LED

Note:

Pressing the Power On Button on the
Front of the iMac When the Computer
is:

Powered On iMac goes immediately to sleep, unless a server

Powered Off iMac powers on

Sleeping iMac wakes from sleep

Result

is mounted, then a dialog box appears

Table 2: Keyboard Button Functionality

Pressing the Keyboard Button When
the iMac is:

Powered On A dialog box appears to choose sleep or shutdown

Powered Off iMac powers on

Sleeping iMac wakes from sleep

Result

Troubleshooting Logic Board Battery - 13

Logic Board Battery

Important:

handling the logic board. Make sure to use proper ESD protection
when handling modules.

The battery on the logic board controls the stored system settings,
such as date and time. It is only necessary to test the battery when
you can’t power on the computer, or the date and time are reset
every time the AC power is removed.

The battery is also used to power the PMU chip (because the PMU
chip keeps time and must always be running) when the computer
is unplugged from the wall (AC power). The PMU is
and touching any circuitry that is connected to the PMU can cause
it to crash. If the PMU crashes, the battery life goes from about
five years to about two days if the PMU is not reset. Once the bat­tery goes dead, the PMU will reset the time and date to 12:00 AM
1/1/04 every time the AC power is removed. To fix this situa­tion, replace the battery and reset the PMU (refer to “Resetting
the PMU on the Logic Board” mentioned earlier in this chapter).

If the computer has a “No Power” situation, check the battery
before replacing modules. When checking the battery, make sure
the computer is unplugged. Measure the voltage across the bat­tery’s BT1 positive and ground terminals. The battery should read

3.3 volts to 3.7 volts. If it’s lower than 3.2 volts, replace the
battery and reset the PMU chip.

Apple highly recommends removing the battery when

sensitive

very

: The iMac uses a lithium battery that must be disposed of in

Note

accordance with hazardous waste regulations.

Troubleshooting Ejecting a CD or DVD Disc, Part 1 - 1 4

Ejecting a CD or DVD Disc, Part 1

The CD/DVD eject mechanism is electrical rather than mechanical
on the iMac. If you wish to eject a bootable CD-ROM disc at
startup, simply hold down the mouse button until it ejects. If the
CD is not a bootable disc, simply wait for the iMac to boot and drag
the CD icon to the trash can.

If this fails to release the CD, there is an eject button which can be
activated by a small, blunt object such as a paper clip. The button
is located on the right side of the CD slot. Note that the power must
be on to eject a CD using this method.
button to eject a CD, you must restart the iMac in order to restore
functionality of the CD/DVD drive. If you don’t, you will not be
able to mount any subsequent discs that are inserted after you use
the emergency eject button.

Once you use the eject

Note:

If the CD/DVD discs still won’t eject after pressing the manual
eject button, remove the bottom housing, and then replace the
bottom housing ensuring that the center tab of the bottom housing
is properly aligned.

Troubleshooting Ejecting a CD or DVD Disc, Part 2 - 1 5

Ejecting a CD or DVD Disc, Part 2

There are two internal levers on a slot-loading CD-DVD drive that
help center a CD-DVD disc. Some CDs and DVDs have and uneven
edge which can cause enough friction to prevent the disc from
ejecting. If this happens, follow these steps:

1 Take a large paperclip and unbend it so that you can insert it

into the CD/DVD slot (as shown below) about 1.5 inches from
the left edge of the slot.

2 With the other hand, drag the disc icon on the desktop to the

Trash to force the computer to eject the disc.

3 When you hear the disc attempt to eject, slide the paperclip to

the left edge of the slot and then remove the paperclip. You
should feel a little resistance from the spring loaded centering
lever. Once the disc has been successfully ejected, wipe the
outside edge of the CD/DVD with your hands. Cleaning the edge
of the disc in this way will reduce the likelihood of the disc
becoming stuck again.

Troubleshooting HFS Plus Formatted Drives - 1 6

HFS Plus Formatted Drives

The hard drive in the iMac is formatted with HFS Plus (also
referred to as Mac OS Extended format). It is important to note
that Norton Utilities version 3.5 is not compatible with HFS Plus
(or Mac OS Extended format), and in fact, can destroy data on the
hard drive.

Norton Utilities version 3.5.3 or 3.5.2 will not attempt to repair
a drive formatted with Mac OS Extended format and versions 3.5.1
and earlier cannot recognize that a hard drive is in Mac OS
Extended format and can result in hard drive corruption and loss
of all data on the drive.

When diagnosing hard drive problems, it is important to

Note:

verify whether or not the customer may have used the wrong disk
repair software for their drive before assuming that the problem
is hardware related.

If you experience problems with a hard drive that has been
formatted with HFS+, Apple Computer recommends using Disk
First Aid (which is included on the system software CD that ships
with the iMac). Disk First Aid can be used to recover data that may
have been deleted by Norton Utilities. (See the Symantec Web site
at http://www.symantec.com/nu/num-hfs.html for more
information on Norton Utilities and Mac OS Extended format.)

Some other disk utility and disk locking programs are
incompatible with Mac OS Extended format. Before you attempt to
use a disk utility or disk locking program, make sure the version
you have is compatible with Mac OS Extended format. Check the
documentation that came with the program or contact the
manufacturer or the vendor that supplied the program.

Use the Get Info command to determine how a hard drive has been
formatted. Drives formatted with HFS will appear as “Mac OS
Standard”, while drives formatted with HFS+ will appear as “Mac
OS Extended.”

For more information on HFS Plus formatting of hard drives,
refer to the Technical Info Library, article # 30344.

Troubleshooting Testing the Modem - 1 7

Testing the Modem

The iMac ships with AppleWorks software, which can be used to
test the iMac modem connection. You should run this test if the
modem is not able to dial out. To perform this test:

1. Locate and launch AppleWorks.

2. From the AppleWorks New Document window, select
Communications and click OK. You will be presented with an
untitled communications document.

3. Click on the settings menu item and select Connection from the
menu, which will bring up a new window. This window allows
you to select the communications toolbox device to access the
modem.

4. Click and hold the menu next to Method and select the Serial Tool
from the options presented.

5. Click on the Internal Modem setting under the Current Port
setting. After selecting the port, click the OK button. (You can
ignore the rest of the settings.)

6. Open the serial port by selecting Open Connection from the
Session menu.

7. Type “AT” into the Communications document. The modem
should respond with an OK message.

This procedure verifies that the program is connecting with the
modem and that the modem is responding.

Troubleshooting Testing the Modem - 1 8

A good test to see if the phone line is working is to type “ATDT”,
which will open the phone line. If the modem reports NO DIAL­TONE, there isn't a valid analog line connected. If the phone line
works, you will hear a dial tone until you press the Return key, at
which time the modem will report NO CARRIER. A No Carrier
message means the phone line was successfully opened.

Other things that can be done here are:

• Call another modem to verify connections.

• Call a working phone number to see if you can successful
connect to an outside line.

• Use the ATI1-17 commands to check firmware versions and
modem features.

• Use ATZ to reset the modem back to its original configuration.

Troubleshooting Symptom/Cure Tables:Startup Problems Before the Finder

Symptom/Cure Tables:Startup Problems Before the Finder Appears

If you have trouble starting up the iMac, and the problem occurs
before the Finder appears on the screen, you may have either a
software or a hardware problem.

Following are troubleshooting tables with problem symptoms that
you may see before the Finder appears. Possible causes for each
symptom can be found in the left-hand column with the corre­sponding fixes in the right-hand column. The troubleshooting
information is presented in the order of the most probable cause
and fix; therefore, Apple strongly recommends that you carry out
the troubleshooting in the order in which it is presented.

: If you are instructed to replace a module and this does not

Note

fix the problem, be sure to reinstall the original module before
you proceed to the next fix.

Troubleshooting Symptom/Cure Tables:Startup Problems Before the Finder Appears

No Power

In a “No Power” situation, the system is completely dead. There is no LED, no hard
drive power, and the screen is completely black. (Refer to “Testing for Power” ear­lier in this chapter for instructions on how to test for power at each component refer­enced in this procedure.)

Possible Cause Possible Fix

Bad power cord, connec­tion, or outlet.

Improperly aligned front
power-on button

Bad USB keyboard. - Verify the keyboard cable is connected properly to the

The PMU chip needs to be
reset.

- Verify the power outlet is good.

- Try a known-good power cord to determine if the
existing power cord could be the problem. Make sure
the power cord is connected securely at both ends.

-If the front power-on LED is not centered properly
within the inner button, the inner power button can
become stuck between the LED and the inner bezel
resulting in a no power, intermittent shut down, or
sleep situation. Refer the LED Alignment procedure in
the Adjustments chapter or to TIL article 58622 for
steps to resolve the LED alignment issue.

computer.

- Disconnect the keyboard and power on the system via
the button on the front of the computer. Do you have
power to the system now?

Yes: The keyboard is bad. Replace the keyboard.

No: Go to next step.

- Press the PMU chip on the logic board with the AC
power cord disconnected. (See “The PMU Chip” and
“Resetting the PMU on the Logic Board” mentioned
earlier in this chapter.)

- Connect the power cord and power on the system again.
Do you have power to the system now?

Yes: Test the unit with MacTest Pro and return the

computer to the customer.

No: With the AC power cord connected, reset the PMU

chip again. Do you have power to the system now?

Yes: The battery is likely bad, check the battery.

No: Go to the next step.

Troubleshooting Symptom/Cure Tables:Startup Problems Before the Finder Appears

In a “No Power” situation, the system is completely dead. There is no LED, no hard
drive power, and the screen is completely black. (Refer to “Testing for Power” ear­lier in this chapter for instructions on how to test for power at each component refer­enced in this procedure.)

Possible Cause Possible Fix

Bad power/analog/video
board

-Verify the fuse at F901 on the power/analog board is
good. (Refer to “Testing for Power at the Power/
Analog Board Fuse” mentioned earlier in this
chapter.) Did you get a “0” reading?

Yes: Check/reseat all power/analog/video board cable

connections. Make sure the video board is securely
attached to the CRT neck. If the No Power problem
persists, go on to the next step.

No: Replace the power/analog/video board.

Bad power/analog/video
board

- Check for trickle power on the logic board (Refer to
“Testing J9 for +5 V Trickle Power on the Logic
Board” mentioned earlier in this chapter). Trickle
power is present as soon as the power cord is plugged
into the computer.
Did you measure +5 V trickle power on pin 1 of
connector J9?

: Go to the next step.

Yes

Replace the power/analog/video board.

No

:

Bad down converter board - Check for DCO voltage at location C10 on the logic board

(Refer to “Testing DCO (Down Converter On) Voltage
at C10 on the Logic Board”) mentioned earlier in this
chapter). Did you measure approximately

-1.2 volts?

: Go on to the next step.

Yes

: Replace the down converter board.

No

Bad LED Power Switch
Board

- Replace the LED/power switch board (922-4160).

If that doesn’t solve the problem, go on to the next step.

Bad CRT - Replace the CRT.

Troubleshooting Symptom/Cure Tables:Startup Problems Before the Finder Appears

No Video or Unstable Raster

Normal startup boot chime, the LED is on, and the hard drive starts up. The display,
however, is solid gray.

Possible Cause Possible Fix

Corrupted PRAM. - Reset parameter RAM. Hold down <Command> <Option>

<P> <R> during startup before “Welcome to Macin­tosh” appears.

Corrupted system soft­ware.

The PMU chip or logic
board needs to be reset.

Bad video cable connection. - Verify that the CRT video board cables, the RGB cable,

- Boot off the system CD that came with the unit. Do you
see a normal screen display now?
Yes: Reinstall system software. (You must use the
system software CD that came with the unit to get the
correct version of Mac OS.)
No: Go to next step.

- Press the PMU chip on the logic board with the AC
power cord disconnected. (See “The PMU Chip” and
“Resetting the PMU on the Logic Board” mentioned
earlier in this chapter.)

- Connect the power cord and power on the system again.
Do you have power to the system now?

Yes: Test the unit with MacTest Pro and return the

computer to the customer.
No: Plug in the AC power cord and reset the PMU chip
again. Do you have power to the system now?

Yes: The battery is likely bad, check the battery.
No: Go to the next step.

and P701 (the deflection yoke cable on the power/
analog board) are securely attached. If the problem
persists go on to the next step.

Bent CRT neck pins. - Remove the CRT video board. Check that the pins on the

CRT neck are not bent. Carefully reseat the CRT video
board and power on the computer. Do you have video
now?
Yes: Run MacTest Pro and return the computer to the
customer.

No: Go on to the next step.

Troubleshooting Symptom/Cure Tables:Startup Problems Before the Finder Appears

Normal startup boot chime, the LED is on, and the hard drive starts up. The display,
however, is solid gray.

Possible Cause Possible Fix

Bad power/analog/video
board

Bad logic board Check for DCO voltage at location C10 on the logic board

Bad internal RGB video
cable.

- Check for trickle power on the logic board (Refer to
“Testing J9 for +5 V Trickle Power on the Logic
Board” mentioned earlier in this chapter). Trickle
power is present as soon as the power cord is plugged
into the computer.
Did you measure +5 V trickle power on pin 1 of
connector J9?

: Go to the next step.

Yes

Refer to the troubleshooting symptom “No Power”.

No:

(Refer to “Testing DCO (Down Converter On) Voltage
at C10 on the Logic Board”) mentioned earlier in this
chapter). Did you measure approximately

-1.2 volts?

: Go to the next step.

Yes

: Replace the logic board.

No

- Replace the internal RGB video cable that attaches to
the power/analog/video board and to the logic board.
The cable is screwed to the power/analog board,
located near the AC power plug on the power/analog
board.

- If this doesn’t solve the problem, go to the next step.

Bad power/analog/video - Replace the power/analog/video board.

Bad CRT. - Replace the CRT.

Troubleshooting Symptom/Cure Tables:Startup Problems Before the Finder

Gray Screen

In a “Gray Screen Raster” situation, you will get a normal startup boot chime and the
system will have a green LED. The display, however, will have a solid gray screen with
no cursor or desktop displayed.

Possible Cause Possible Fix

Corrupted system software. - Boot off the system CD that came with the unit. Do you

see a normal screen display now?
Yes: Reinstall system software. (You must use the
system software CD that came with the unit to get the
correct version of Mac OS.)
No: Go to next step.

The PMU chip or logic board
needs to be reset.

Bad video cable connection. - Verify that the CRT video board and video board cables

Bad SDRAM - Reseat/replace the SDRAM with known-good SDRAM.

Bad logic board - Replace the logic board.

Bad power/analog/video
board

- Press the PMU chip on the logic board with the AC

power cord disconnected. (See “The PMU Chip” and
“Resetting the PMU on the Logic Board” mentioned
earlier in this chapter.)

- Connect the power cord and power on the system again.

Do you have power to the system now?

Yes: Test the unit with MacTest Pro and return the

computer to the customer.

No: Plug in the AC power cord and reset the PMU chip

again. Do you have power to the system now?

Yes: The battery is likely bad, check the battery.

No: Go to the next step.

going to and from the power/analog board are securely
attached. If the problem persists go on to the next step.

- Replace the power/analog/video board.

Bad CRT -Replace the CRT.

Troubleshooting Symptom/Cure Tables:Startup Problems Before the Finder

Error Beep(s)

If you hear from one to five error beeps at startup with no boot chime, you have a
hardware problem. The table explains how to troubleshoot and repair an iMac unit
that sounds one or more error beeps at startup.

Possible Cause Possible Fix

No DRAM is installed or
detected.

Incompatible RAM is
installed.

Bad RAM. Do you hear three error beeps at startup?

Bad ROM. Do you hear four or five error beeps at startup?

Do you hear one error beep at startup?
Yes: Follow these steps to resolve the problem:

1. Make sure the DRAM are PC-100 SDRAM. Reseat
the SDRAM and try again.

2. If no SDRAM is present, install a known-good
PC-100 SDRAM and try again.

3. If DRAM is present, replace DIMM one at a time,
with a known-good PC-100 SDRAM.

No: Go to next step.

Do you hear two error beeps at startup?

Yes: Verify that only SDRAM PC-100 DIMMs are

installed (The iMac ships with PC-100 SDRAM
memory and is not compatible with EDO

DIMMs.)

No: Go to next step.

Yes: Replace the existing SDRAM one DIMM at a time

with known-good PC-100 SDRAM.

No: Go to next step.

Yes: Replace the logic board.

No: If you do not hear any error beeps at startup, you

have a different problem and should refer to one of the
other troubleshooting tables in this chapter.

Troubleshooting Symptom/Cure Tables:Startup Problems Before the Finder Appears

Flashing Question Mark

This problem refers to a flashing question mark that appears on the screen during star­tup.

Possible Cause Possible Fix

Corrupted system software
or software drivers.

Bad cable connections, or
bad hard drive.

Boot from the system CD that came with the unit. Can you

see the hard drive on the desktop?

Yes: The system software is most likely the problem.

Reinstall system software. (You must use the system
software CD that came with the unit to get the correct
version of Mac OS with the appropriate iMac
enablers.)

No: The hard drive or its software drivers are most

likely the problem. Can you see the hard drive using
Drive Setup?

Yes: Use Drive Setup to reinstall the software

drivers for the hard drive. If the problem persists,
use Drive Setup to reinitialize the hard drive (See TIL
article #22206 for Drive Setup information.)

Warning: You will lose all data on the hard drive

when you reinitialize it. Backup the data first if
possible.

No: Go to next step.

If you don’t see the hard drive using Drive Setup:

1. Check all cable connections to and from the hard drive.

2. Replace the HD/CD/DVD data cable.

3. Replace the hard drive.

4. Replace the hard drive power cable.

5. Replace the logic board.

Troubleshooting Symptom/Cure Tables:Startup Problems Before the Finder Appears

System Hangs During Boot

This problem refers to a system that begins a normal startup process with a boot
chime and normal display, but then freezes before the Finder appears.

Possible Cause Possible Fix

System extensions caus­ing a conflict.

Corrupted system software
or bad SDRAM.

Bad hard drive. Can you see the hard drive using Drive Setup?

Boot with Extensions off by holding down the Shift key

during startup. (See TIL article #14343 for more
information on possible Extension conflicts.) Does the
system startup successfully with Extensions off?

Yes: Begin adding back the system Extensions one at a

time and starting up the system after each addition. If
the system freezes again, you know that the last
Extension you added is causing the problem.

No: Go to the next step.

Boot from the system CD that came with the unit. Does

the system startup successfully?

Yes: Reinstall system software. (You must use the

system software CD that came with the unit to get the
correct version of Mac OS.)If the problem persists, go
to the next step.

No: Reseat the SDRAM. If the problem persists,

replace the SDRAM (one DIMM at a time) with known-
good PC-100 SDRAM.

Yes: Use Drive Setup to reinstall the software

drivers for the hard drive. If the problem persists,
use Drive Setup to reinitialize the hard drive.
(See TIL article #22206 for Drive Setup
information.) Warning: You will lose all data on
the hard drive when you reinitialize it. Back up the
data first if possible.
No: Go to next step.

Bad hard drive, cables, or
cable connections.

If you don’t see the hard drive using Drive Setup:

1. Check all cable connections to and from the hard drive.

2. Replace the HD/CD/DVD data cable.

3. Replace the hard drive.

4. Replace the hard drive power cable.

5. Replace the logic board.
If the problem persists, go on to the next step.

Troubleshooting Symptom/Cure Tables:Startup Problems Before the Finder Appears

This problem refers to a system that begins a normal startup process with a boot
chime and normal display, but then freezes before the Finder appears.

Possible Cause Possible Fix

External device is bad. Disconnect all external devices (USB and Ethernet). Then

begin reconnecting these devices one at a time
(beginning with the keyboard and then the mouse) and
start up the computer after each device is connected to
see if one of the external devices is causing the
problem. If the problem occurs after you connect a
particular external device, replace the device in
question.

Troubleshooting Symptom/Cure Tables: System Problems After Startup - 29

Symptom/Cure Tables: System Problems After Startup

If you experience system problems after a successful startup
(i.e., after the Finder appears on the screen), most likely the
problem is not with the iMac hardware (with the exception of
some possible RAM issues).

Following are troubleshooting tables with problem symptoms that
you may see after the Finder appears. Possible causes for each
symptom can be found in the left-hand column with the corre­sponding fixes in the right-hand column. The troubleshooting
information is presented in the order of the most probable cause
and fix; therefore, Apple strongly recommends that you carry out
the troubleshooting in the order in which it is presented.

Note: If you are instructed to replace a module and this does not fix

the problem, be sure to reinstall the original module before you
proceed to the next fix.

Power Macintosh 7500 Symptom Charts - 30

System Hangs

Refer to this table if your system intermittently hangs (freezes) during normal oper­ation. Note: if your system only hangs when using a specific application, the problem
is most likely with the application and not with your iMac hardware or system soft­ware. If this table does not solve the problem, refer to the “Software Troubleshooting”
manual on Service Source (under the Troubleshooting tab) for more comprehensive
information.

Possible Cause Possible Fix

System Extensions causing
a conflict.

Corrupted system soft­ware.

Bad USB device. Turn off the computer and disconnect all USB devices.

Boot with Extensions off by holding down the Shift key
during startup. (See TIL article #14343 for more
information on possible Extension conflicts.) Does the
system startup successfully with Extension off?

Yes: Begin adding back the system Extensions one at a

time and starting up the system after each addition. If
the system freezes again, you know that the last
Extension you added is causing the problem.

No: Go to the next step.

Boot from the system CD that came with the unit. Does
the problem recur?

Yes: Go to next step.
No: The system software is most likely the problem.

Reinstall system software. (You must use the system
software CD that came with the unit to get the correct
version of Mac OS.)

Next, power on the system using the power button on
the front of the unit, and begin adding back the USB
device one at time, beginning with the keyboard and
then the mouse, and so on. If the system hangs only
after you reconnect a particular USB device, replace
that USB device.

Bad memory. Run MacTest Pro in loop mode overnight to test for bad

memory. If MacTest Pro finds a bad memory module,
or other hardware, replace the hardware in question
with a known-good module.

Bad logic board. Replace the logic board.

Troubleshooting Symptom/Cure Tables: System Problems After Startup - 31

Distorted Video

Distorted Video refers to a problem with the screen geometry or focus.

Possible Cause Possible Fix

System is out of focus. Adjust the focus using the Display Adjustment Utility on

the MacTest Pro CD. (See “Focus” in the iMac
Adjustments chapter for instructions.)

Screen geometry is out of
adjustment (display is off
center, sides or top of the
screen are not straight,
etc.).

Screen cutoff or white bal­ance is out of adjustment.

Adjust the screen geometry using the Display Adjustment
Utility on the MacTest Pro CD. (See “Geometry” in the
iMac Adjustments chapter for instructions.)

Adjust the cutoff or white balance using the Display
Adjustment and Display Service Utilities on the MacTest
Pro CD. (See “Video” in the iMac Adjustments chapter
for instructions.)

Troubleshooting Symptom/Cure Tables: System Problems After Startup - 32

Thin White Line

A a thin, white horizontal line scrolls from top to bottom, or bottom to top on the iMac
display.

Possible Cause Possible Fix

Display may need adjust­ing.

Power/analog/video board
is faulty

Adjust the cutoff or white balance using the Display
Adjustment and Display Service Utilities on the MacTest
Pro CD. (See “Video” in the iMac Adjustments chapter
for instructions.)

Replace the power/analog/video board.

Troubleshooting Symptom/Cure Tables: System Problems After Startup - 33

Tinting Video

Tinting Video refers to a predominant color tint or color covering the screen.

Possible Cause Possible Fix

Environmental causes. Verify that the iMac unit is not near other equipment

(such as speakers, radios, phones, fluorescent lighting,
magnets, or other electronic equipment) that could affect
the video display. If necessary, move the iMac computer
to another area and restart the unit.

Loose video cables. Reseat the video cables connecting from the power/analog

board to the video board. Make sure that both ends of the
cable are firmly seated into their connectors.

Loose video board. Reseat the video board on the CRT neck. Make sure the

CRT neck screw is secure.

Color is out of adjustment. Adjust the white balance using the Display Adjustment

and Display Service Utilities on the MacTest Pro CD.
(See “Video” in the iMac Adjustments chapter for
instructions.)

Bad power/analog/video
board.

Bad RGB video cable. Replace the internal RGB video cable that runs between

Bad Logic Board. Replace the logic board.

Replace the power/analog/video board.

the power/analog board and the P301 and P302 on the
video board.

Troubleshooting Symptom/Cure Tables: System Problems After Startup - 34

Garbage Video

Garbage video refers to erroneous text or characters that appear on the screen.

Possible Cause Possible Fix

Corrupted system soft­ware.

Bad logic board. Replace the logic board.

Boot from the system CD that came with the unit. Open
the Monitors and Sound control panel and change the
Maximum Resolution and Color Depth to their maximum
settings. Restart the unit. Does the screen display appear
normal now?

Yes: Reinstall system software. (You must use the

system software CD that came with the unit to get the
correct version of Mac OS.) If the problem persists, go

to the next step.

No: Go to next step.

Troubleshooting Symptom/Cure Tables: System Problems After Startup - 35

Intermittent Shut Down or Sleep

An iMac with a sticking power button can generate unpredictable behavior. The iMac
randomly shuts itself off or puts itself to sleep. The iMac will not start up from either
the front power button or the keyboard.

Possible Cause Possible Fix

Improperly aligned front
power-on button

-If the front power-on LED is not centered properly
within the inner button hole, the power button can
become stuck between the LED and the inner bezel
resulting in a no power, intermittent shut down, or
sleep situation. Refer the LED Alignment procedure in
the Adjustments chapter or to TIL article 58622 for
steps to resolve the LED alignment issue.

Troubleshooting Symptom/Cure Tables: System Problems After Startup - 36

Memory Error Dialog

If you see a error dialog message pertaining to memory after you have a successful
startup sequence (that is, a normal boot tone with no error beeps and proper video
display, etc.) then refer to the table below to troubleshoot the problem.

Possible Cause Possible Fix

Dialog message reads “The
built-in memory test has
detected a problem. Please
contact a service provider
for assistance.”

Run Mac TestPro to locate the bad SDRAM. Replace the

SDRAM with a known-good PC-100 SDRAM DIMM.

Troubleshooting Symptom/Cure Tables: System Problems After Startup - 37

Can’t Wake From Sleep

The computer cannot be brought out of “sleep” mode by pressing a key on the key­board. The problem is usually evident by a black screen and a pulsing amber LED.

Possible Cause Possible Fix

PMU Press the PMU chip on the logic board with the AC

power cord disconnected. (See “The PMU Chip” and
“Resetting the PMU on the Logic Board” mentioned
earlier in this chapter.)

Connect the power cord and power on the system again.

Do you have power to the system now?

Yes: Test the unit with MacTest Pro and return the

computer to the customer.

No: Plug in the AC power cord and reset the PMU chip

again. Do you have power to the system now?

Yes: The battery is likely bad, check the battery.
No: Go to the next step.

Bad keyboard Try a known-good keyboard.

Corrupted PRAM Reset the PRAM by holding down the Option–Command–

P–and R keys

Software Conflict Reinstall System Software. You must use the system

software that came with the unit in order to get the
correct version of Mac OS. Note: If the computer
sleeps while connected to the Internet, and is running
Mac OS 8.6 or Mac Os 9.0, download Apple Audio
Update 1.3 from the Apple Software Update page.

Bad logic board Replace the logic board.

Troubleshooting Symptom/Cure Tables: System Problems After Startup - 38

Network Problems

Refer to this troubleshooting table if you are unable to switch to the Ethernet network
option in the control panel or if you are unable to see any network devices.
are able to see most network devices, but one particular device does not show up in
the Chooser, troubleshoot the device in question. You most likely do not have a net­work problem.

Possible Cause Possible Fix

Note: if you

Wrong option selected in
the Control Panel.

Corrupted PRAM. Reset parameter RAM. Hold down Command >Option> <P>

Corrupted system soft­ware.

Bad Ethernet cable. Replace the Ethernet cable with a known-good cable.

Bad Ethernet port at the
wall or hub.

Open the Network control panel and select the Ethernet

option. Are you able to select the Ethernet option?

Yes: Verify that you can now see devices on the

network. If the problem persists, go to the next step.

No: Go to next step.

<R> during startup but before “Welcome to Macintosh”
appears.

Boot from the system CD that came with the unit. Open

the Network control panel and switch to Ethernet. Are
you able to switch to Ethernet and see Ethernet devices
on the network now?

Yes: Reinstall system software. (You must use the

system software CD that came with the unit to get the
correct version of Mac OS.) If the problem persists, go

to the next step.

No: Go to next step.

Try connecting to a different Ethernet port at the wall or

external hub. Are you able to switch to Ethernet and
see Ethernet devices on the network now?

Yes: The original Ethernet port is bad. Contact your

network administrator.

No: Go to next step.

The entire network is
down.

Are other users experiencing the same problem?

Yes: There is a network-wide problem. Contact your

network administrator.

No: Replace the logic board.

Troubleshooting Symptom/Cure Tables: System Problems After Startup - 39

CD_ROM or DVD-ROM Vibration

CD-ROM or DVD-ROM vibration is typically caused by unbalanced discs when spinning
at higher speeds in the internal CD-ROM or DVD-ROM drive. This vibration may cause
the drive to have difficulty reading the disc.

Possible Cause Possible Fix

Bad CD-ROM or DVD-ROM
disc.

Try using a known-good compact disc.

Troubleshooting Symptom/Cure Tables: System Problems After Startup - 40

CD-ROM or DVD-ROM Won’t Eject

CD-ROM or DVD-ROM disc won’t eject from the slot.

Possible Cause Possible Fix

Bad CD-ROM or DVD-ROM
disc.

1 Press and hold down the mouse buton on startup.

Note: This only works on iMac computers with Boot

ROM version 2.3 or higher. To check the Boot ROM
version, open Apple System Profiler/System Profile
tab/Production information/Boot ROM Version.

2 Try manually ejecting the disc. Push a paper clip

through the manual eject hole located on the right
side of the CD/DVD slot. Refer to “Ejecting a CD or
DVD Disc, Part 1 earlier in this chapter”.

3 Restart the iMac after the disc ejects. If you don’t

restart, you will not be able to mount any subsequent
discs that are inserted after you use the manual eject
button.

Note: The power must be on to eject a CD or DVD disc.

If this doesn’t solve the problem, continue with the
procedures on the next page.

Troubleshooting Symptom/Cure Tables: System Problems After Startup - 41

CD-ROM or DVD-ROM disc won’t eject from the slot.

Possible Cause Possible Fix

Uneven edge of the CD or
DVD drive.

There are two internal levers on a slot-loading CD-DVD
drive that help center a CD-DVD disc. Some CDs and DVDs
have and uneven edge which can cause enough friction to
prevent the disc from ejecting. If this happens, follow
these steps:

1 Take a large paperclip and unbend it so that you can

insert it into the CD/DVD slot (as shown below)
about 1.5 inches from the left edge of the slot.

2 With the other hand, drag the disc icon on the desktop

to the Trash to force the computer to eject the disc.

3 When you hear the disc attempt to eject, slide the

paperclip to the left edge of the slot and then remove
the paperclip. You should feel a little resistance from
the spring loaded centering lever. Once the disc has
been successfully ejected, wipe the outside edge of the
CD/DVD with your hands. Cleaning the edge of the disc
in this way will reduce the likelihood of the disc
becoming stuck again.

Bottom housing not aligned
properly.

Bad CD-ROM or DVD-ROM
drive.

Remove the bottom housing, and then replace the bottom
housing. Ensure the tabs on the bottom housing align with
the tab slots on the front outer bezel. Pay particular
attention to the alignment of the center tab. Refer to the
take-apart procedures for removing and reseating the
bottom cover.

Replace CD/DVD drive mechanism.

Troubleshooting Symptom/Cure Tables: System Problems After Startup - 42

CD-ROM or DVD-ROM Not Showing on Desktop

CD-ROM and DVD-ROM problems are defined by the inability to see the CD or DVD on
the desktop or to open a CD or DVD that is loaded into the drive.

Possible Cause Possible Fix

Bad CD-ROM or DVD-ROM
disc.

CD-ROM or DVD-ROM disc
didn’t load properly.

Corrupted system software If the CD-ROM or DVD-ROM drive fails to mount, boot off

Master/Slave switch set
incorrectly on the back of
the CD-ROM or DVD-ROM
drive.

Loose cable. Check all cables running to and from the CD-ROM or

Try using a known-good compact disc.

Manually eject the disc and try again. Push a paper clip
through the manual eject hole located on the right side of
the CD/DVD slot. Restart the iMac after the disc ejects.
Note: The power must be on to eject a CD or DVD disc.

the system CD that came with the unit. Do you see the
CD-ROM or DVD-ROM drive on the desktop now?

Yes: Reinstall system software. (You must use the sys-

tem software CD that came with the unit to get the cor­rect version of the Mac OS.)

No: Go to the next step.

Make certain the Master/Slave switch (located under the
CD Adapter board) on the drive is set to Slave. The Slave
position is the switch closest to the CD Adapter connector
on the back of the CD-ROM or DVD-ROM drive. The
switch is set correctly at the drive vendor, but it may
have been moved by mistake.

DVD-ROM drive at both ends and make sure they are
attached securely.

Bad CD-ROM or DVD-ROM
drive.

Bad HD/CD/DVD data cable. Replace the HD/CD/DVD data cable.

Bad logic board. Replace the logic board.

Replace CD-ROM or DVD-ROM drive.

Troubleshooting Symptom/Cure Tables: System Problems After Startup - 43

Hard Drive Problems

Hard drive problems include a hard drive that doesn’t operate (it doesn’t spin) or a
hard drive that doesn’t mount (it doesn’t appear on the desktop).

Possible Cause Possible Fix

Corrupted drivers. Can you see the hard drive using Drive Setup?

Yes: Use Drive Setup to reinstall the software

drivers for the hard drive. If the problem persists,
use Drive Setup to reinitialize the hard drive.
(See TIL article # 22206 for instructions.)
Warning: You will lose all data on the hard drive
when you reinitialize it. Backup the data first if
possible.

No: Go to next step.

Bad hard drive, cables, or
cable connections.

If you don’t see the hard drive using Drive Setup:

1. Check all cable connections to and from the hard drive.

2. Replace the HD/CD/DVD data cable.

3. Replace the hard drive.

4. Replace the hard drive power cable.

Troubleshooting Symptom/Cure Tables: System Problems After Startup - 44

Sound Out Problems

Sound out problems refer to a lack of sound coming from the internal speakers (located
on the front of the unit directly below the display), external speakers (connected via
the I/O panel to the speaker connector on the logic board), or both.

Possible Cause Possible Fix

Control Panel setting is
incorrect.

Corrupted PRAM. Reset parameter RAM. Hold down <Command> <Option>

Loose speaker connection. Verify that both ends of the internal speaker cables are

Loose audio cable. - Reseat the audio cable (922-4039) located on the

First, disconnect any external microphones, speakers or
headphones. Next, verify that volume setting in Control
Panel is adequate and that mute is not checked. Test the
for sound coming from the internal speakers. Do you
have sound now?

Yes: If the initial sound out problem was with the

internal speakers, the problem is solved. If you
reconnect the external sound out device and it is not
working, the problem may be with the external device
itself or its cable. Replace the external microphone,
speaker, or headphone in question with a known-good
device. If the problem persists, replace the logic
board.

No: Go to next step.

<P> <R> during startup but before “Welcome to Macin­tosh” appears.

attached securely.

divider panel, under the CRT.

Bad audio cable. - Replace the audio cable (922-4039).

Bad speakers. - Replace the speakers.

Bad logic board. Plug known-good headphones or external speakers into

the external jack. Do you get sound?

Yes: Go to next step.

No: Replace the logic board.

Bad headphone board. - Replace the headphone board.

Troubleshooting Symptom/Cure Tables: System Problems After Startup - 45

Sound In Problems

Sound in problems involve the internal microphone. Symptoms could be: audio record­ing quality is poor, a high level of background noise is noticeable, or no sound is
recorded.

Possible Cause Possible Fix

Sound control panel. Open the Simple Sound Control Panel (found under the

Apple Menu). Select CD Quality under the Sound menu to
minimize noise on the internal microphone. Did this solve
the problem?

Yes: If the initial sound in problem was with the

sound control panel; the problem is solved.

No: Go to next step.

Loose audio cable. Reseat the audio cable (922-4039).

Bad audio cable. Replace the audio cable (922-4039).

Bad microphone. Replace the internal microphone.

Troubleshooting Symptom/Cure Tables: System Problems After Startup - 46

Noise From Computer After Shutdown

After the computer is shutdown, the computer emits a loud humming or buzzing noise
that may continue for minutes or until the power cord is removed.

Possible Cause Possible Fix

Logic Board Replace the logic board.

Troubleshooting Symptom/Cure Tables: System Problems After Startup - 47

USB Problems

USB problems refer to symptoms or issues that may occur with external USB devices
that are attached to the iMac. This could include Apple and/or third-party USB devices.

Possible Cause Possible Fix

Not enough power for the
USB device to function.

The following error message will appear confirming that a
device cannot function at all due to a lack of power. This
lack of power (depending on the device) can be a result
of a disconnected external power source, or not enough
power available from the hub the device is connected to.
The two corrective steps listed in the dialog box (shown
on the next page) provide the user guidance in
troubleshooting these conditions.

USB device experiencing a
partial lack of power.

Similar to the first error message, this error message indicates
a device may not completely function due to a partial lack of
power and gives steps to remedy the problem.

Troubleshooting Symptom/Cure Tables: System Problems After Startup - 48

USB problems refer to symptoms or issues that may occur with external USB devices
that are attached to the iMac. This could include Apple and/or third-party USB devices.

Possible Cause Possible Fix

USB driver missing. This error message indicates the device's driver is miss-

ing. Customers will need to check the instructions that
came with the device and install the Mac OS driver.

Bad USB connector. Connect the problem device directly into one of the iMac

USB ports or, if it’s already connected to one of the
iMac USB ports, switch it to the other port.

Bad USB device. Replace the USB device.

Bad logic board. Replace the logic board.

Troubleshooting Symptom/Cure Tables: System Problems After Startup - 49

Cursor Problems

This section deals with a cursor that moves on the screen, but clicking the mouse has
no effect or double-clicking the mouse does not open an application, disk or server.

Possible Cause Possible Fix

Corrupted PRAM. Reset parameter RAM. Hold down <Command> <Option>

<P> <R> during startup but before “Welcome to Macin­tosh” appears.

Corrupted system soft­ware.

Bad USB port on the key­board.

Bad USB port on the iMac. If the mouse is already connected to one of the USB

Bad mouse. Replace mouse.

Bad logic board. Replace logic board.

Boot off the system CD that came with the unit. Does the
cursor work now?

Yes: Reinstall system software. (You must use the

system software CD that came with the unit to get the

correct version of Mac OS.)

No: Go to next step.

If the mouse is connected to the keyboard, connect the
mouse to one of the USB ports inside the iMac I/O panel
instead. Does the cursor work now?

Yes: Replace the keyboard.

No: Replace the mouse.

ports inside the iMac I/O panel, switch it to the other
USB port. Does the cursor work now?

Yes: Replace the logic board.

No: Go to next step.

Troubleshooting Symptom/Cure Tables: System Problems After Startup - 50

USB Printer Problems

This troubleshooting table deals with an iMac that cannot print to an attached, known-

good

USB printer.

Possible Cause Possible Fix

Printer is not compatible
with the iMac USB bus.

Chooser is set incorrectly. Open the Chooser and verify that you have the correct

Bad printer driver or hard­ware problem.

Bad external USB port. If the printer is connected to a third-party hub, switch

Bad USB port on the iMac. If the printer is already connected to a USB port on the

Verify with the manufacturer of the printer that it is
iMac compatible.

printer and printer driver selected.

Use Apple System Profiler to see if it recognizes that a

USB printer is connected.

Yes: Reinstall the printer driver.
No: The printer or its cable is malfunctioning.

Replace the cable or printer.

it to one of the iMac ports in the I/O panel. Does the
printer work now?

Yes: You have a bad third-party hub. Replace the

device that contains the problem USB port or refer to
the third-party documentation for troubleshooting
procedures.

No: Go to next step.

iMac, switch it to the other USB port. Does the printer
work now?

Yes: Replace the logic board.
No: Go to next step.

System software is cor­rupted.

Bad cable. Replace the printer interface cable.

Bad logic board. Replace the logic board.

Perform a clean install of the system software using the
Mac OS CD that shipped with the iMac. (You must use the
system software CD that came with the iMac in order to
get the correct version of Mac OS 8.1 with the appropri­ate iMac enablers.)

Troubleshooting Symptom/Cure Tables: System Problems After Startup - 51

Networked Printer Problems

This troubleshooting table deals with an iMac that cannot print to an attached, known-

good

networked printer.

Possible Cause Possible Fix

Bad network connections. Check the network connections.

Wrong version of system
software is installed.

Chooser is set incorrectly. Open the Chooser and verify that you have the correct

System, network, or
printer software is cor­rupted.

General network problems. Refer to the “Network Problems” troubleshooting table

Bad logic board. Replace the logic board.

Verify that you have the correct version of Mac OS. If you

are unsure, reinstall the system software using the
original CD that shipped with the iMac unit.

printer and printer driver selected.

Perform a clean install of the system software (you must
use the system software CD that came with the iMac in
order to get the correct version of Mac OS with the
appropriate iMac enablers) and/or the network and
printer software.

earlier in this chapter.

Troubleshooting Symptom/Cure Tables: System Problems After Startup - 52

Modem Not Recognized

This table should help you troubleshoot and fix problems when the internal modem is
not recognized. Follow the instructions under the “Possible Fix” column to resolve the
problem.

Possible Cause Possible Fix

Modem Is Not Recognized: If the modem is not recognized or listed in the

application or OS, refer to this section of the table.

Needed extensions or CCL
files are not installed or are
corrupt.

Are the correct CCL and extension files installed? (Note:
You will need the iMac Modem Extension and the iMac
internal modem CCL.)

Yes: The CCL or extension may be corrupt. Reinstall

the CCL and modem extension. If the problem persists,
reinstall the system software and try again.

No: Install the correct CCL and modem extension and

try again.

PRAM is corrupt. Zap PRAM by holding down Option, Command– P–and R

keys.

Serial Port Not Available message: If the Modem Control Panel and/or AppleWorks

reports that the serial port is not available, refer to this section of the table.

The modem is loose, miss­ing, or bad.

Is the modem installed?

Yes: Reseat the modem and try again. If the

problem persists, replace the modem board.

No: Install a modem and try again.

Troubleshooting Symptom/Cure Tables: System Problems After Startup - 53

Modem Dialing Problems

If the modem is having problems dialing out, refer to the table below for possible fixes.
The table is divided into different sections, each with its own symptom and cure(s).
Find your symptom and then follow the instructions under the “Possible Fix” column to
resolve the problem.

Note: A good first step in troubleshooting a modem problem is to

verify the modem connection as explained in “Testing the Modem” earlier in this chap­ter.

Possible Cause Possible Fix

No Dial Tone: If the system gives you a No Dial Tone error message, refer to this

section of the table.

The phone line is not con­nected.

Is the phone line connected securely to the computer
and to the wall jack?

Yes: Go to the next step.

No: Reconnect the phone line at both ends and try

again.

The phone line is dead. Plug a phone into that line. Do you get a dial tone?

Yes: There does not appear to be a problem with the

phone line. Test the modem as explained in “Testing
the Modem” earlier in this chapter.

No: Report the dead phone line to the phone company.

There is a problem with
the modem.

Modem Cannot Dial Out: If there is a dial tone, but the user cannot dial out with the

Reseat the modem. If the problem persists, replace the
modem.

modem, refer to this section of the table.

The modem settings are
incorrect.

Open the modem control panel and make sure the
modem type selected is iMac Internal 56K, (or Apple
iMac internal modem in the Earthlink setup screen) the
sound is On, and the dialing is set to Tone. At this point,
leave the ignore dial tone setting unselected.

The incorrect CCL file is
selected or it is damaged.

There is a problem with the
phone line or dial tone set­tings.

The modem is loose or
missing.

Verify you have the correct CCL selected. If the problem
persists, reinstall the CCL file.

Can you get a normal dial tone with the modem?

Yes: Go to the next step.

No: Some voice mail systems use a beeping dial tone to

notify the user of waiting messages, which can affect
the modem connection. Open the modem control panel
and select Ignore Dial Tone.

If you get an error message that the modem is not
found, verify that the modem is installed and properly
seated. If the problem persists, replace the modem.

K

Service Source

T ak e Apart

iMac, iMac DV, iMac DV Special

Edition

Take Apart - 1

Tools

The following tools are recommended for procedures in this
chapter:

• phillips screwdriver (#1 and #2)

• a stubby (short) phillips screwdriver

• plastic flatblade screwdriver to release tabs on plastic
housing

• jeweler’s screwdriver

• CRT discharge tool

• needlenose pliers

• ESD mat

Take Apart Bottom Housing With Flip Foot - 2

Procedures

Bottom Housing With Flip Foot

Before you begin, position
the computer face down,
resting the computer on an
ESD mat or other soft
surface.

Take Apart Bottom Housing With Flip Foot - 3

1. Remove the two screws
near the flip foot.

2. Using a plastic flatblade
screwdriver, pry the
VGA vented cover off the
bottom housing to access
two more screws.

There are two

Note:

service parts for the
vented cover. One cover
has an opening for the
video out port, and the
other cover does not.

3. Remove the video out
access door from the
bottom housing.

Take Apart Bottom Housing With Flip Foot - 4

4. Remove the two outer
screws located near the
video out port.

The bottom

Note:

housing uses two sizes of
screws. The two shorter
screws attach near the
flip foot.

Take Apart Bottom Housing With Flip Foot - 5

5. Lift the bottom housing
from the computer.

Take Apart Bottom Housing With Flip Foot - 6

6.

Replacement Caution:

Align the three tabs on
the bottom housing with
the tab slots on the front
outer bezel.

Ensure that the center
tab is properly aligned
or CDs and DVD discs
may not eject from the
slot.

7. Lower the bottom
housing into place and
replace the screws.

Take Apart EMI Cover - 7

EMI Cover

Before you begin:

• Position the computer

upside down, resting the
computer on an ESD mat
or other soft surface.

• Remove the bottom

housing.

Take Apart EMI Cover - 8

1. Remove the six screws
on the EMI cover.

Take Apart EMI Cover - 9

2. Lift the EMI cover off the
computer.

Note:

Be careful of the
VGA output port (if
present).

Take Apart EMI Cover - 10

Replacement Note:

Position
the rear of the EMI cover
into place first, positioning
the EMI cover over the video
port (if present). Continue
lowering the cover into
place by gently squeezing in
on both sides, as you lower
the cover into position.

Take Apart SDRAM DIMM - 1 1

SDRAM DIMM

Before you begin, position
the computer face down,
resting the CRT on an ESD
mat or other soft surface.

Take Apart SDRAM DIMM - 1 2

1. With a flatbade

screwdriver or coin,
turn the colored latch
counterclockwise on the
access door.

2. Open the access door.

Take Apart SDRAM DIMM - 1 3

3. Push down on the plastic

tabs to release the
SDRAM module(s).

4. Carefully lift the SDRAM

from the slot.

Note:

Remove installed
SDRAM from the logic board
before returning the logic
board to Apple.

Take Apart AirPort Card - 14

AirPort Card

Before you begin, position
the computer face down,
resting the CRT on an ESD
mat or other soft surface.

If the AirPort Card is

Note:

not installed, a protective
antenna cap will be attached
to the antenna.

Take Apart AirPort Card - 15

1. With a flatbade

screwdriver or coin,
turn the colored latch to
open the access door.

The antenna and AirPort
Card will be visible
when you open the access
door.