Apple Macintosh Quadra Centris 840AV Service Manual
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Service Source
Macintosh Quadra 840AV
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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.
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