Apple Macintosh Quadra Centris 840AV Service Manual

K

Service Source

Macintosh Quadra 840AV

K

Service Source

Specifications

Macintosh Quadra 840AV

Specifications Processor - 1

Processor

CPU

Addressing

Direct Memory Access (DMA)

Motorola 68040 microprocessor
40 MHz
Built-in paged memory management unit (PMMU), floating-point

unit (FPU), and 8K memory cache

32-bit registers
32-bit address/data bus

A Peripheral Subsystem Controller (PSC) provides direct

memory access (DMA) between the 68040 buses and
peripheral devices.

Specifications Processor - 2

Digital Signal Processor (DSP)

AT&T DSP3210 32-bit floating-point digital signal processor
Supports real-time tasks such as speech recognition, audio

compression, and analog modem signal processing.

Specifications Memory - 3

Memory

RAM

ROM

PRAM

8 MB standard (one 8 MB SIMM), expandable to 128 MB
72-pin SIMMs
Requires CAS-before-RAS
60 ns access time

2 MB soldered on logic board

256 bytes of parameter memory

Specifications Memory - 4

VRAM

Clock/Calendar

1 MB standard, expandable to 2 MB (80 ns or faster 256K VRAM

SIMMs)
Maximum pixel depths for 1 MB / 2 MB VRAM:
12-inch color (512 x 384) - 16 / 16 bits per pixel
12-inch monochrome (640 x 480) - 16 / 16 bits per pixel
13-inch color (640 x 480) - 8 / 16 bits per pixel
15-inch portrait (640 x 870) - 4 / 8 bits per pixel
16-inch color (832 x 624) - 8 / 16 bits per pixel
19-inch color (1024 x 768) - 4 / 8 bits per pixel
21-inch monochrome (1152 x 870) - 4 / 8 bits per pixel
21-inch color (1152 x 870) - 4 / 8 bits per pixel
VGA (640 x 480) - 8 / 16 bits per pixel
SVGA (800 x 600) - 8 / 16 bits per pixel

Apple custom chip with long-life lithium battery

Specifications Disk Storage - 5

Disk Storage

Floppy Drive

Hard Drive

CD-ROM Drive

Internal, 1.4 MB Apple SuperDrive

Internal, 3.5 in. hard drive (230, 500, 1000 MB) optional

Internal, CD-300 mechanism optional

Specifications I/O Interfaces - 6

I/O Interfaces

Serial

Two RS-232/RS-422 ports (modem port is an Apple high-

performance serial port)
Printer port: mini DIN-8 connector
Modem port: mini DIN-9 connector (also supports mini DIN-8

connector)

230.4 Kbaud maximum

0.920 mbit/sec. if external clock source is provided (modem

interface only)
Asynchronous and synchronous communications supported up to

9600 baud

Specifications I/O Interfaces - 7

GeoPort (Modem Port)

Video

S-Video Input & Output

High-performance serial port
Supports connection to analog, PBX, ISDN, facsimile (fax), and

data telephone lines
Provides full-duplex telephone I/O at up to 14.4 Kbps
Supports AppleTalk and V.22, V.22bis, V.29, and V.32 modem

protocols
Supports Apple HiPPort protocols

One monitor port; DB-15 connector
Supports Apple monitors (up to 16-bits), VGA monitors, and

NTSC and PAL video standards

One S-video output port; one S-video input port; mini DIN-4

connectors
Supports input/output in NTSC, PAL, and SECAM formats

Specifications I/O Interfaces - 8

Composite Video Input & Output

Ethernet

Floppy Disk

SCSI

One composite video output port; one composite video input port;

RCA phono plug connectors
Supports input/output in NTSC, PAL, and SECAM formats

One Ethernet port; AUI-15 connector

Supports one internal 1.4 MB Apple SuperDrive
Supports industry-standard 765 or Apple group code recording

(GCR) formats

One SCSI port; DB-25 connector
Supports a maximum of eight devices (including the computer,

which is always device 7)
Transfers data at a maximum rate of 5 Mbps (synchronous)
Automatic termination of internal and external SCSI buses

Specifications I/O Interfaces - 9

NuBus

Expansion

Three slots; 96-pin Euro-DIN connectors
Supports standard-size cards, block transfers, burst-mode

transfers, a processor write buffer, power control service,

and NuBus ‘90 data transfers between cards at 20 MHz
One slot supports NuBus cards that contain a Digital Audio and

Video (DAV) connector

One 68040 processor-direct slot (PDS); 140-pin connector

Specifications I/O Interfaces - 10

Audio

Apple Desktop Bus

One 16-bit stereo output port; one 16-bit stereo input port; mini

phone-jack connectors
Sample rates up to 48 kHz (44.1 kHz standard rate)
Uses the digital signal processor (DSP) chip
Supports stereo audio from internal CD drive and Apple PlainTalk

microphone
Audio input port characteristics: 26K ohms impedance, 2 V rms

maximum, 22.5 dB gain
Audio output port characteristics: 37 ohms impedance, 0.9 V rms

maximum, attenuated –22.5 dB

One Apple Desktop Bus (ADB) port for keyboard, mouse, and low-

speed input devices; mini DIN-4 connector

Specifications I/O Devices - 11

I/O Devices

Keyboard

Mouse

Microphone

Apple Keyboard, Apple Extended Keyboard, Apple Keyboard II, or

Apple Extended Keyboard II (optional); mini DIN-4 connector

Apple Desktop Mouse or Apple Desktop Mouse II; mini DIN-4

connector

Electret, omnidirectional; output voltage is 4 mV, peak to peak, at

normal value; mini phone plug connector
Designed for speech recording and recognition

Specifications Sound and Video - 12

Sound and Video

Video Display

Sound Generator

Built-in VRAM video support for all Apple monitors; four VRAM

expansion slots (two banks)
Supports Apple 16-bit monitors and many non-Apple monitor

types (NTSC, PAL, VGA)
Multiple external color and monochrome monitors through NuBus

expansion slots

Enhanced Apple sound chip (EASC), including four-voice wave

table synthesis and stereo sampling generator capable of

driving stereo mini phone-jack headphones or stereo

equipment

Specifications Electrical - 13

Electrical

Line V oltage

Frequency

Maximum Power

Power for SCSI Devices

100–240 VAC

50–60 Hz, single phase

200 W continuous

Maximum continuous power available for each SCSI device:

1.5A @ +5 V

4.3A @ +12 V

Specifications Electrical - 14

Power for NuBus Cards

Maximum continuous power available for each NuBus card:

2.0A @ +5 V

0.175A @ +12 V

0.15A @ –12 V

Specifications Physical - 15

Physical

Dimensions

Weight

Height: 14.25 in. (360 mm)
Width: 7.75 in. (196 mm)
Depth: 16 in. (396 mm)

24 lb. (11.3 kg)

Specifications Environmental - 16

Environmental

Operating Temperature

Storage Temperature

Relative Humidity

Altitude

50–104° F (10°–40° C)

–40 to 116.6° F (–40 to 47° C)

5–90% noncondensing

0–10,000 ft. (0–3048 m)

K

Service Source

Troubleshooting

Macintosh Quadra 840AV

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 Symptom Charts/Error Chords - 2

Symptom Charts

Error Chords

One-part error
chord sounds during
startup sequence

Two-part error chord
sounds during
startup sequence

1 Disconnect SCSI data cable from hard drive and reboot

system. If startup sequence is normal, initialize hard drive.
If error chord still sounds, replace hard drive.

2 Disconnect floppy drive cable from floppy drive and reboot

system. If startup sequence is normal, replace floppy drive.

3 Replace logic board. Retain customer’s SIMMs.

Perform SIMMs verification.

Troubleshooting Symptom Charts/System - 3

System

Does not power on;
screen is black, fan is
not running, and LED
is not lit

1 Check power cables.
2 Plug monitor directly into wall socket, and verify that

monitor has power.
3 Reset logic board. (Refer to Additional Procedures.)
4 Replace power cord.
5 Replace power supply.
6 Replace logic board. Retain customer’s SIMMs.

Troubleshooting Symptom Charts/System

(Continued)

- 4

Clicking, chirping,
or thumping sound
from power supply

System

1 Remove all NuBus expansion cards and disconnect all

2 Replace power supply.
3 Replace logic board. Retain customer’s SIMMs.

(Continued)

internal peripherals (hard drives, CD-ROM drives, floppy

drives, etc.) and power-on system again. If system powers

on normally, reconnect one device at a time and replace

NuBus expansion cards one at a time, powering on the system

after each reconnection/reinstallation. The defective module

is identified when the symptom reappears

Troubleshooting Symptom Charts/System

(Continued)

- 5

System shuts down
intermittently

System

1 Make sure air vents are clear. Thermal protection circuitry

2 Check battery. Refer to “Battery Verification” in Additional

3 Replace power cord.
4 Replace power supply.
5 Replace logic board. Retain customer’s SIMMs.

(Continued)

may shut down system. After 30 to 40 minutes, system

should be OK.

Procedures.

Troubleshooting Symptom Charts/System

(Continued)

- 6

System
intermittently
crashes or hangs

Intermittent shut­downs from a cold boot

System

1 Verify that system software is version 7.1 or later.
2 Verify that software is known-good.
3 Verify that software is System 7 compatible.
4 Clear parameter RAM. Hold down <Command> <Option> <P>

5 Replace SIMMs.
6 Replace logic board. Retain customer’s SIMMs.
7 Replace power supply.

Replace power supply.

(Continued)

<R> during startup but before “Welcome To Macintosh”

appears.

Troubleshooting Symptom Charts/Video - 7

Video

Screen is black, audio
and drive operate, fan
is running, and LED is
lit

1 Adjust brightness on monitor.
2 Replace monitor. Refer to appropriate monitor manual to

troubleshoot defective monitor.
3 Replace video cable.
4 If video interface card is installed, move it to different slot.
5 Replace video card, if installed.
6 Clear parameter RAM. Hold down <Command> <Option> <P>

<R> during startup but before “Welcome To Macintosh”

appears.
7 Replace SIMMs.
8 Replace logic board. Retain customer’s SIMMs.
9 Replace power supply.

Troubleshooting Symptom Charts/Video

(Continued)

- 8

Screen is black, audio
and drive do not
operate, but fan is
running and LED is lit

Partial or whole
screen is bright and
audio is present, but
no video information
is visible

Video

1 Replace video cable.
2 If video interface card is installed, move it to different slot.
3 Replace video interface card, if installed.
4 Replace SIMMs.
5 Replace logic board. Retain customer’s SIMMs.
6 Replace power supply.

1 Replace monitor. Refer to appropriate monitor manual to

2 Replace video cable.
3 If video interface card is installed, move it to different slot.
4 Replace video interface card, if installed.
5 Clear parameter RAM. Hold down <Command> <Option> <P>

6 Replace logic board. Retain customer’s SIMMs.

(Continued)

troubleshoot defective monitor.

<R> during startup but before “Welcome To Macintosh”

appears.

Troubleshooting Symptom Charts/Floppy Drive - 9

Floppy Drive

Internal floppy drive
does not operate

During system
startup with a floppy
disk, disk ejects;
display shows icon
with blinking “X”

1 Replace disk with known-good floppy disk.
2 Replace floppy drive cable.
3 Replace floppy drive.
4 Replace logic board. Retain customer’s SIMMs.
5 Replace power supply.

1 Replace disk with known-good system disk.
2 Clear parameter RAM. Hold down <Command> <Option> <P>

<R> during startup but before “Welcome To Macintosh”

appears.
3 Replace floppy drive cable.
4 Replace floppy drive.
5 Replace SIMMs.
6 Replace logic board. Retain customer’s SIMMs.

Troubleshooting Symptom Charts/Floppy Drive

(Continued)

- 10

Floppy Drive

Does not eject disk 1 Switch off computer. Hold mouse button down while you

switch computer on.
2 Replace floppy drive cable.
3 Replace floppy drive.
4 Replace logic board. Retain customer’s SIMMs.

Attempts to eject
disk, but doesn’t

Internal floppy drive
runs continuously

1 Push disk completely in.
2 Reseat floppy drive bezel and drive so bezel slot aligns

correctly with drive.
3 Eject disk manually.
4 Replace floppy drive.

1 Replace disk with known-good floppy disk.
2 Replace floppy drive cable.
3 Replace floppy drive.
4 Replace logic board. Retain customer’s SIMMs.

(Continued)

Troubleshooting Symptom Charts/Floppy Drive

(Continued)

- 11

MS-DOS drive does
not recognize a disk
formatted on a 1.4 MB
drive

Floppy Drive

To read and write files with either MS-DOS or 1.4 MB drive,
format all disks with MS-DOS drive first.

(Continued)

Troubleshooting Symptom Charts/Hard Drive - 12

Hard Drive

Single internal hard
drive does not
operate; drive
doesn’t spin

No internal SCSI
devices operate

Drive does not appear
on the desktop

1 Replace hard drive power cable.
2 Replace hard drive.
3 Replace power supply.

1 Verify there are no duplicate SCSI device addresses—internal

and external.
2 Replace SCSI data cable.
3 Replace power supply.
4 Replace logic board. Retain customer’s SIMMs.

1 Verify there are no duplicate SCSI device addresses.
2 Clear parameter RAM. Hold down <Command> <Option> <P>

<R> during startup but before “Welcome To Macintosh”

appears.
3 If drive is not initialized, use HD SC Setup to initialize.

Troubleshooting Symptom Charts/Hard Drive - 13

4 Replace hard drive.

Works with internal
or external SCSI
devices but not with
both

1 Verify there are no duplicate SCSI device addresses.
2 Replace terminator on external SCSI device.
3 Verify that SCSI device at end of internal SCSI data cable is

only device terminated.
4 Refer to appropriate manual to troubleshoot defective

external device.

Troubleshooting Symptom Charts/Peripherals - 14

Peripherals

Cursor does not move 1 Check mouse connection.

2 Inspect inside of mouse for buildup of dirt or other

contaminants. Clean mouse if necessary.
3 If mouse was connected to keyboard, connect mouse to

computer ADB port instead. If mouse works, replace

keyboard.
4 If mouse does not work in any ADB port on computer, replace

mouse.
5 Replace logic board. Retain customer’s SIMMs.

Cursor moves, but
clicking mouse
button has no effect

1 Replace mouse.
2 Replace logic board. Retain customer’s SIMMs.

Troubleshooting Symptom Charts/Peripherals

(Continued)

- 15

Double-click doesn’t
open selected item

No response to any
key on keyboard

Peripherals

1 Remove duplicate system folders.
2 Clear parameter RAM. Hold down <Command> <Option> <P>

<R> during startup but before “Welcome To Macintosh”

appears.
3 If mouse was connected to keyboard, connect mouse to

computer ADB port instead. If mouse works, replace

keyboard.
4 If mouse does not work in any ADB port on computer, replace

mouse.
5 Replace logic board. Retain customer’s SIMMs.

1 Check keyboard connection to ADB port.
2 Replace keyboard cable.
3 Replace keyboard.
4 Replace logic board. Retain customer’s SIMMs.

(Continued)

Troubleshooting Symptom Charts/Peripherals

(Continued)

- 16

Known-good serial
printer does not work

Known-good network
printer does not print

Peripherals

1 Verify that system software is version 7.1 or later.
2 Verify that Chooser is set correctly.
3 Replace printer interface cable.
4 Replace logic board. Retain customer’s SIMMs.

1 Verify that system software is version 7.1 or later.
2 Verify that Chooser is set correctly.
3 Replace logic board. Retain customer’s SIMMs.

(Continued)

Troubleshooting Symptom Charts/Miscellaneous - 17

Miscellaneous

No sound from
speaker

1 Verify that volume setting in Control Panel is 1 or above.
2 Replace speaker.
3 Replace logic board. Retain customer’s SIMMs.

Troubleshooting Symptom Charts/CD-ROM Drive - 18

CD-ROM Drive

CD-ROM drive does
not accept compact
disc

Macintosh does not
display CD-ROM icon

1 Exchange disc.
2 Replace CD-ROM drive mechanism.

1 Verify that CD-ROM software is installed.
2 Replace CD-ROM drive mechanism.
3 Replace SCSI data cable.
4 Replace power supply.

K

Service Source

T ak e Apart

Macintosh Quadra 840AV

Take Apart Cover - 1

Cover

Cover

No preliminary steps are
required before you begin
this procedure.

1 Loosen the four captive

cover screws.

2 Slide the cover forward

about 1/2 inch and lift
the cover from the
computer.

Cover
Screw

Take Apart Floppy Drive - 2

Floppy Drive

Before you begin, remove
the cover.

Floppy Drive

Caution

precautions in Bulletins/
Safety.

: Review the ESD

Take Apart Floppy Drive - 3

1 Press down the retaining

clip securing the floppy
drive and slide the
floppy drive forward
about 2 inches.

2 Disconnect the floppy

drive cable from the
floppy drive.

3 Remove the floppy drive

from the chassis.

Replacement Note:

dust shields on 1.4 MB
drives in the Quadra 840AV.
All 1.4 MB replacement
drives ship with the dust
shield already installed.

Install

Take Apart Hard Drive - 4

Hard Drive

Before you begin, remove
the cover.

Hard Drive

Caution

precautions in Bulletins/
Safety.

: Review the ESD

Take Apart Hard Drive - 5

1 Disconnect the SCSI data

cable and hard drive
power cable from the
hard drive.

2 Press down the retaining

clip securing the hard
drive and slide the hard
drive out.

Replacement Note:

information on removing the
hard drive from the carrier
and returning drives,
cables, and carriers to
Apple, refer to Additional
Procedures in the Hard
Drives manual.

For

Take Apart CD-ROM Drive - 6

CD-ROM Drive

Before you begin, remove
the cover.

CD-ROM Drive

Caution:

precautions in Bulletins/
Safety.

Review the ESD

Take Apart CD-ROM Drive - 7

SCSI Data Cable

CD-ROM Audio Cable

Power Cable

1 Disconnect the following

cables from the CD­ROM drive:

• SCSI data cable

• CD-ROM audio cable

• CD-ROM power cable

Take Apart CD-ROM Drive - 8

2 Pull up on the retaining

clip securing the CD­ROM drive and slide the
CD-ROM drive out.

Replacement Note:

the floppy drive cable is
seated firmly in its channel
before replacing the CD­ROM drive. Failure to do so
could result in damage to the
floppy drive cable.

Replacement Note:

to remove the CD-ROM drive
from the carrier prior to
returning the drive to Apple.

Be sure

Be sure

Take Apart Logic Board - 9

Logic Board

Before you begin, remove
the cover.

Logic Board

Caution:

precautions in Bulletins/
Safety.

Review the ESD

Take Apart Logic Board - 10

CD-ROM

Audio Cable

Floppy Drive

Cable

LED Cable

Speaker

Cable

Cable Data Cable

SCSI Power

1 Disconnect the following

cables from the logic
board:

• SCSI data cable

• Logic board power
cable

• Speaker cable

• CD-ROM audio cable

• Floppy drive cable

• LED cable

Take Apart Logic Board - 11

Power-On Actuator

2 Remove the power-on

actuator.

Take Apart Logic Board - 12

3 Remove the screw

securing the logic board.

Take Apart Logic Board - 13

4 Slide the logic board

forward until the slot

Latch

indicated lines up with
the tab.

5 Lift the latch at the rear

of the logic board and
release the logic board.

Tab

Take Apart Logic Board - 14

6 Pivot the front of the

logic board out of the
chassis and stand the
logic board on the static
mat next to the
computer.

7 Disconnect the composite

video input and output
connector cables from
the logic board.

Composite Video Input and
Output Connectors

Take Apart Power Supply - 15

Power Supply

Before you begin, remove
the cover.

Power Supply

Caution:

precautions in Bulletins/
Safety.

Review the ESD

Take Apart Power Supply - 16

1 Remove the chassis

support brace.

Chassis Support
Brace

Take Apart Power Supply - 17

2 Disconnect the logic

board power cable.

Logic Board

Power Cable

Take Apart Power Supply - 18

3 Press the latch and

release the power
supply.

Latch

Take Apart Power Supply - 19

4 Slide the power supply

forward.

5 Pull the power supply

out of the computer.

Power Supply

Take Apart Speaker - 20

Speaker

Before you begin, remove

Speaker

Speaker
Cable

the cover.

Caution:

precautions in Bulletins/
Safety.

1 Disconnect the speaker

Review the ESD

cable from the logic
board.

Take Apart Speaker - 21

2 Press the latch holding

the speaker housing to
the chassis and lift the
front of the speaker
housing.

3 Pull the speaker

housing from the clips at
the rear of the chassis.

Latch

Take Apart Rear Cover - 22

Rear Cover

Before you begin, remove
the following:

• Cover

• Speaker

Rear Cover

Caution:

precautions in Bulletins/
Safety.

Review the ESD

Take Apart Rear Cover - 23

1 Lift the two latches and

pull the rear cover
loose.

Latch

Take Apart Rear Cover - 24

2 Remove the rear cover

from the computer.

K

Service Source

Upgrades

Macintosh Quadra 840AV

Upgrades Expansion Cards - 1

Expansion Cards

Before you begin, remove
the cover.

NuBus Card

Retainer

Caution:

precautions in Bulletins/
Safety.

1 Pinch the two handles

Review the ESD

and remove the NuBus
card retainer.

Upgrades Expansion Cards - 2

2

Caution:

on both sides of the card
to avoid bending the
connector pins.

Carefully grasp each end
of the card and pull
straight out to remove it.

Note:

of the card by the metal
bracket.

Pull up evenly

Grab the left side

Replacement Caution:

Do not force the card into
the expansion slot. If the
card does not seat
properly, remove it and
try again.

Upgrades CD-ROM Upgrade - 3

CD-ROM Upgrade

CD-ROM Drive

Before you begin, remove
the cover.

Caution:

precautions in Bulletins/
Safety.

Review the ESD

Upgrades CD-ROM Upgrade - 4

Bezel

1 Remove the upper blank

bezel from the top cover.

2 Install the slotted CD-

ROM drive bezel in the
top cover.

Upgrades CD-ROM Upgrade - 5

3 Attach the CD-ROM

CD-ROM Carrier

carrier to the CD-ROM
drive with four Phillips
screws.

CD-ROM Drive

Upgrades CD-ROM Upgrade - 6

Jumper Connectors

4 Verify that the two

jumper connectors are
installed as shown.

Important:

These
jumpers configure the
SCSI device address of
the CD-ROM drive. The
CD-ROM drive will have
a SCSI device ID of 2.
Verify that no other SCSI
device installed in the
computer already has
that address. If another
device does have an ID of
2, change the ID prior to
installing the CD-ROM
drive.

Upgrades CD-ROM Upgrade - 7

5 Slide in the CD-ROM

CD-ROM Drive and Carrier

drive and carrier.

Upgrades CD-ROM Upgrade - 8

6 Connect these cables to

the CD-ROM drive:

SCSI Data

Cable

CD-ROM Drive

Power Cable

Audio Cable

• Audio cable

• SCSI data cable

• CD-ROM drive power

cable

Upgrades Power Macintosh Upgrade - 9

Power Macintosh Upgrade

No preliminary steps are
required before you begin
this procedure.

The Quadra 840AV can be
upgraded to a Power
Macintosh 8100/80 or
Power Macintosh 8100/
80AV. For upgrade
instructions, refer to
Additional Procedures in the
Power Macintosh 8100
manual.

Upgrades Power Macintosh 8500 Upgrade - 10

Power Macintosh 8500 Upgrade

The Power Macintosh 8500 Upgrade Kit can be used to
upgrade a Quadra 800, Quadra 840, or a Power Macintosh

8100. The kit includes everything except:

• The peripherals (such as the hard drive, floppy drive,
and CD-ROM drive), which must be transferred from
the original unit you are upgrading

• A processor card, which must be purchased separately.

Refer to the appropriate Take Apart chapter (that is, the
Take Apart chapter in the Quadra 800, Quadra 840AV, or
Power Macintosh 8100 manual) for instructions on how to
remove the drives from the original unit.

Refer to the Take Apart chapter in the Power Macintosh
8500/WS 8550 manual to see where the peripherals should
be installed in the upgraded unit and for instructions on how

Upgrades Power Macintosh 8500 Upgrade - 11

to install the processor card.

Once you have installed all the drives in the upgraded unit
and replaced the top housing, copy the serial number from
the original unit to the blank serial label on the upgraded
unit.

K

Service Source

Additional Procedures

Macintosh Quadra 840AV

Additional Procedures Battery Verification - 1

Battery Verification

Before you begin, remove
the following:

• Cover

Battery

• Logic Board

Caution:

precautions in Bulletins/
Safety.

±

discarded improperly, the
battery could explode. Re­view battery handling and
disposal instructions in
Bulletins/Safety.

Review the ESD

Warning:

If handled or

Additional Procedures Battery Verification - 2

1 Set the voltmeter to the

10 volts DC scale.

2 Hold the positive probe

of the voltmeter to the
positive end of the
battery (marked “+”
on the logic board) and
the negative probe to the
negative end of the
battery.

3 If the battery voltage is

below 3.2 volts, replace
the battery. Refer to
“Battery Replacement”
in this chapter.

Additional Procedures Battery Replacement - 3

Battery Replacement

Before you begin, remove
the following:

• Cover

Battery

• Logic Board

Caution:

precautions in Bulletins/
Safety.

±

discarded improperly, the
battery could explode. Re­view battery handling and
disposal instructions in
Bulletins/Safety.

Review the ESD

Warning:

If handled or

Additional Procedures Battery Replacement - 4

1 Using a small flat-blade

screwdriver, pry open
the latch at the end of the
battery holder and lift
off the cover.

Additional Procedures Battery Replacement - 5

2 Grasp the battery and

remove it from the
holder.

3 Return the battery to

Apple for proper
disposal. For battery
packaging and labeling
instructions, refer to
the safety information in
Bulletins/Safety.

Additional Procedures Reset Logic Board - 6

Reset Logic Board

Before you begin, remove the following:

• Cover

• Power Cord

• Logic Board

Caution:

±

lithium battery in the Quadra 840AV could explode. Review
battery handling and disposal instructions in Bulletins/
Safety.

Note:

should follow this procedure to reset the logic board
replacing any modules.

Review the ESD precautions in Bulletins/Safety.

Warning:

Whenever you have a unit that fails to power up, you

If handled or discarded improperly, the

before

Additional Procedures Reset Logic Board - 7

1 Unplug the computer

first.

2 Using a small flat-blade

screwdriver, pry open
the latch at the end of the
battery holder and lift
off the cover.

Additional Procedures Reset Logic Board - 8

3 Grasp the battery and

remove it from the
holder.

Additional Procedures Reset Logic Board - 9

4 Press the computer’s power-on button. Verify that the

power supply cable is disconnected from the logic board.
Wait 5—10 minutes and then

• Replace the battery

• Reassemble the computer

Note:

Make sure the battery in installed in the correct +/-

direction.

Note:

This procedure resets PRAM. Be sure to check the

computer’s time/date and other system parameter settings.

K

Service Source

Exploded V ie w

Macintosh Quadra 840AV

Exploded View 1

Top Housing

Thumbscrew

Panel

922-2027

Power

Supply

Cable

922-0838

922-0395

Rear

922-0870

Cable

Composite

Video

922-0847

Speaker

Housing

922-0394

SCSI

Cable

922-0871

Front
Panel
922-2026

Speaker

922-0055

Actuator

922-2030

Brace

922-0396

CD-ROM Bezel

Trayloading

922-0811

On/Off

922-0841

Manual Insert Floppy
Drive Bezel
922-0523

Tape Drive Bezel
922-0969

Logic Board

661-1700

LED

Cable

CD-ROM Bezel w/Caddy
922-0846

Floppy Drive Bezel
922-0849

Blank Bezel
922-0620

Logic Board
Guard
922-0851

CD-ROM
Audio Cable
922-0724

CD-ROM
Drive*
661-0222

CD-ROM
Carrier
922-0850

Floppy Drive
Cable
922-0872

Floppy Drive*
661-0121

Floppy Drive*
Carrier
922-0445

Power

Supply

661-1687

NuBus

Retainer

922-0393

Product family configurations may vary. For parts with asterisk (*), refer to parts list.

Chassis
922-0888

Quadra 840AV

Hard Drive*

Hard Drive
Carrier
922-0621

Tape Drive
661-0795

Tape Drive
Carrier
922-0621