Apple Macintosh Quadra Centris AWS95 Service Manual
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Service Source
Macintosh Quadra 900/950/
AWS 95
Macintosh Quadra 900, Macintosh Quadra 950, Apple
Workgroup Server 95
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Service Source
Basics
Macintosh Quadra 900/950/AWS
95
Basics Overview - 2
Overview
This manual includes
complete repair procedures
for the Quadra 900/950 and
the Apple Workgroup Server
95, pictured at left.
Figure: Macintosh Quadra 900/950 and AWS 95
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Service Source
Specifications
Macintosh Quadra 900/950/AWS
95
Specifications Processor - 1
Processor
CPU
Quadra 900:
Quadra 950 and AWS
95:
Addressing
Motorola 68040 microprocessor
Built-in paged memory management unit (PMMU), floating-point
unit (FPU), and 8K memory cache
25 MHz
33 MHz
32-bit registers
32-bit address bus
32-bit data bus
Specifications Memory - 2
Memory
RAM
Quadra 900
Quadra 950
AWS 95
ROM
PRAM
4 MB standard, expandable to 256 MB (80 ns or faster
SIMMs)
8 MB standard, expandable to 256 MB (80 ns or faster
SIMMs)
16 MB, 32 MB, or 48 MB parity RAM standard, expandable to
256 MB (80 ns or faster 9-bit SIMMs)
1 MB, using two 150 ns, 256K by 16-bit chips
256 bytes of parameter memory
Specifications Memory - 3
VRAM
Clock/Calendar
1 MB, expandable to 2 MB (100 ns or faster VRAM SIMMs) by
installing four 256K or two 512K SIMMs
ASIC clock chip with PRAM and DFAC support and seven-year
lithium battery
Specifications Disk Storage - 4
Disk Storage
Floppy Drive
Hard Drive
Quadra 900 and 950
AWS 95
Internal, 1.4 MB Apple SuperDrive
230, 500, or 1000 MB hard drive (optional)
230, 500, 1000, or 2000 MB hard drive; comes in either a two-
drive or five-drive configuration
Note
: Refer to Take Apart for more information on the twodrive configuration and to Additional Procedures for more
information on the five-drive configuration.
Specifications Disk Storage - 5
DDS-DC Drive
2 GB digital data storage-data compression drive for 4 mm tape
backup; available as an upgrade on the Quadra 900 and 950;
optional on the AWS 95
Specifications I/O Interfaces - 6
I/O Interfaces
SCSI
Quadra 900
AWS 95 and Quadra
900/950 (with PDS
card upgrade)
Apple Desktop Bus
One external SCSI port; DB-25 connector
One internal SCSI port with 50-pin IDC connector; Supports a
maximum of eight devices (including the computer, which is
always device 7)
Two internal SCSI ports with 50-pin IDC connectors; Two
external SCSI ports with DB-25 connectors; Supports a
theoretical limit of 20 devices (including the computer, which
is always device 7) on four separate SCSI buses (two internal
and two external); Macintosh Operating System supports only
7 devices
One Apple Desktop Bus (ADB) port; low-speed, synchronous
serial interface
Specifications I/O Interfaces - 7
NuBus
Expansion
Serial
Sound
Five slots support standard and oversize cards, burst-mode
transfers, a processor write buffer, and NuBus '90; 96-pin
Euro-DIN connectors
One 68040 processor-direct slot (PDS) with 140-pin connector
Two RS-232/RS-422 ports with mini DIN-8 connectors;
230.4 Kbits/sec. maximum; 0.920 Mbits/sec. if external clock
source is provided (modem interface only)
Asynchronous, synchronous (modem only), and AppleTalk
(printer only) protocols supported
8-bit stereo output; 8-bit monoaural input
Supports electret-type microphone
Specifications I/O Interfaces - 8
Video
Ethernet
Supports Apple monitors (8-bit), VGA monitors, and NTSC and
PAL video standards
One Ethernet port, AUI-15 connector
Specifications Sound and Video - 9
Sound and Video
Video Display
Sound Generator
Microphone
Built-in 8-bit video circuitry (upgradeable to 24-bit)
Supports Apple 8-bit monitors and many non-Apple monitor
types (NTSC, PAL, VGA)
Four-voice, wavetable synthesis
Stereo sampling generator
Electret, omnidirectional; output voltage is 4 mV, peak to peak,
at normal value
Specifications Electrical - 10
Electrical
Line V oltage
Line Frequency
Maximum Power
100–240 VAC (RMS), self-configuring power supply
50–60 Hz, single phase
303 W (not including monitor)
Specifications Physical - 11
Physical
Dimensions
Weight
Height: 16.8 in. (473 mm)
Width: 8.9 in. (224 mm)
Depth: 20.6 in. (523 mm)
36 lb., 12 oz. (16.7 kg) without hard drive
Specifications Environmental - 12
Environmental
Operating Temp
Storage Temp
Relative Humidity
Altitude
50–104° F (10–40° C)
–40 to 116.6° F (–40 to 47° C)
20–80% noncondensing
0–10,000 ft. (0–3048 m)
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Service Source
Troubleshooting
Macintosh Quadra 900/950/AWS
95
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 General - 2
Error Chords
One-part error
chord sounds during
startup sequence
Two-part error chord
sounds during
startup sequence
1 Disconnect SCSI data cable from logic board and reboot
system. If startup sequence is normal, initialize hard drive.
If error chord still sounds, replace hard drive.
2 Disconnect floppy drive cable connector and reboot system. If
startup sequence is normal, replace floppy drive.
3 Replace logic board. Retain customer's SIMMs.
Perform SIMM verification. Refer to Memory manual.
Troubleshooting General - 3
System Problems
Does not power on;
screen is black, fan is
not running, and LED
is not lit
Clicking, chirping,
or thumping
1 Check power cables.
2 Plug monitor directly into wall socket and verify that
monitor has power.
3 Replace power cord.
4 Replace power supply.
5 Replace logic board. Retain customer's SIMMs.
1 Replace power supply.
2 Replace logic board. Retain customer's SIMMs.
3 Replace floppy drive cable.
4 Replace floppy drive.
Troubleshooting General - 4
System shuts down
intermittently
System Problems
1 Make sure air vents on side and rear of computer are clear.
Thermal protection circuitry may shut down system. After
30 to 40 minutes, system should be OK.
2 Replace power cord.
3 Check battery. Refer to "Battery Verification" in Additional
Procedures.
4 Replace power supply.
5 Replace logic board. Retain customer's SIMMs.
(Continued)
Troubleshooting General - 5
System
intermittently
crashes or hangs
System Problems
1 Verify that system software is correct version.
2 Verify that software is known-good.
3 Verify that software is System 7 compatible.
4 Clear parameter RAM. Hold down <Command> <Option> <P>
<R> during startup but before "Welcome To Macintosh"
appears.
5 Replace SIMMs. Refer to Memory manual.
6 Replace logic board. Retain customer's SIMMs.
7 Replace power supply.
(Continued)
Troubleshooting General - 6
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 a video interface card is installed, move it to a different
slot.
5 Replace video interface card, if installed.
6 Clear parameter RAM. Hold down <Command> <Option> <P>
<R> during startup but before "Welcome To Macintosh"
appears.
7 Replace SIMMs. Refer to Memory manual.
8 Replace logic board. Retain customer's SIMMs.
9 Replace power supply.
Troubleshooting General - 7
Screen is black, audio
and drive do not
operate, but fan is
running and LED is lit
Video
1 Replace video cable.
2 If a video interface card is installed move it to a different
3 Replace video interface card, if installed.
4 Replace SIMMs. Refer to Memory manual.
5 Replace logic board. Retain customer's SIMMs.
6 Replace power supply.
(Continued)
slot.
Troubleshooting General - 8
Partial or whole
screen is bright and
audio is present, but
no video information
is visible
Video
1 Replace monitor. Refer to appropriate monitor manual to
2 Replace video cable.
3 If a video interface card is installed, move it to a different
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.
slot.
<R> during startup but before "Welcome To Macintosh"
appears.
Troubleshooting General - 9
Floppy Drive
Internal floppy drive
does not operate
During system
startup, disk ejects;
display shows icon
with blinking "X"
1 Verify that keyswitch is not set to secure.
2 Replace disk with known-good disk.
3 Replace floppy drive cable.
4 Replace internal floppy drive.
5 Replace logic board. Retain customer's SIMMs.
6 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 internal floppy drive.
5 Replace logic board. Retain customer's SIMMs.
Troubleshooting General - 10
Floppy Drive
Does not eject disk 1 Verify that keyswitch is not set to secure.
2 Switch off computer. Hold mouse button down while you
switch computer on.
3 Replace internal floppy drive.
4 Replace floppy drive cable.
5 Replace logic board. Retain customer's SIMMs.
Attempts to eject
disk, but doesn't
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.
(Continued)
Troubleshooting General - 11
Internal floppy drive
runs continuously
MS-DOS drive does
not recognize a disk
formatted on a 1.4 MB
drive
Floppy Drive
1 Replace disk with known-good system disk.
2 Replace floppy drive cable.
3 Replace internal floppy drive.
4 Replace logic board. Retain customer's SIMMs.
To read and write files with either MS-DOS or 1.4 MB drive,
format all disks with MS-DOS drive first.
(Continued)
Troubleshooting General - 12
Hard Drive
Single internal hard
drive will not
operate; drive doesn't
spin
No internal hard
drives operate
1 Replace hard drive data cable.
2 Replace hard drive power cable.
3 Replace hard drive.
1 Verify there are no duplicate SCSI device addresses.
2 Replace hard drive data cable.
3 Replace power supply.
4 Replace logic board. Retain customer's SIMMs.
Troubleshooting General - 13
Drive does not appear
on the desktop
Works with internal
or external SCSI
devices but not with
both
Hard Drive
1 Verify there are no duplicate SCSI device addresses.
2 Update the SCSI device driver using Apple HD SC Setup. Run
Disk First Aid to verify the condition of the drive's directory
structure.
3 Replace the SCSI hard drive cable.
4 If drive is not initialized, use HD SC Setup to initialize.
5 Replace with known good hard drive. If the hard drive still
doesn't work, switch back to the original hard drive and
replace the logic board.
1 Verify there are no duplicate SCSI device addresses.
2 Replace terminator on external device.
3 Make sure internal hard drives are not terminated.
4 Refer to appropriate manual to troubleshoot defective
external device.
(Continued)
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