Apple Macintosh Powermac Performa 275 Service Manual

K

Service Source

Macintosh Color Classic II/

Performa 275

K

Service Source

Basics

Macintosh Color Classic II/

Performa 275

Basics Overview - 1

Overview

This manual includes
complete repair procedures
for the Macintosh Color
Classic II/Performa 275.

Figure: Color Classic II/Performa 275

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Service Source

Specifications

Macintosh Color Classic II/

Performa 275

Specifications Configurations - 1

Configurations

Standard

Options

4 MB RAM, 256K VRAM, 3.5-in. hard drive (many sizes),

internal 1.4 MB floppy drive, user-removable logic board, 9­in. color display, built-in speaker and microphone, keyboard,
mouse, ADB and power cables, system software installed on
hard drive (requires System 7.1)

Memory expansion kit
256K VRAM SIMM upgrade
Apple IIe emulation card
LC Ethernet card
Math coprocessor
Anti-glare, anti-static CRT

Specifications Processor - 2

Processor

CPU

Coprocessor

Addressing

Motorola 68030 microprocessor
33 MHz
Built-in Paged Memory Management Unit (PMMU)
256-byte instruction and data caches

Socket for optional Motorola 68882 floating-point coprocessor
33 MHz

16-bit data bus
32-bit address bus
16-bit internal registers

Specifications Memory - 3

Memory

RAM

ROM

PRAM

4 MB of dynamic RAM on board
Expandable to 10 MB (100 ns or faster SIMMs)
Dual SIMM expansion slot (two 30-pin connectors)
Includes RAM disk software

1 MB of main ROM on board; 2 MB maximum of main ROM

256 bytes of clock/calendar/parameter memory
Long-life lithium battery

Specifications Memory - 4

VRAM

256K of VRAM on board
Expandable to 512K of VRAM with 256K VRAM SIMM (100 ns or

faster VRAM SIMM)

68-pin VRAM SIMM connector

Specifications Disk Storage - 5

Disk Storage

Floppy Drive

Hard Drive

Internal 1.4 MB Apple SuperDrive

3.5-inch, internal 40, 80, or 160 MB SCSI hard drive

Specifications I/O Interfaces - 6

I/O Interfaces

Serial

SCSI

Apple Desktop Bus

Two RS-232/RS-422 serial ports; mini DIN-8 connectors

One SCSI parallel port; DB-25 connector
Connects up to six external SCSI devices

Two ADB ports; mini DIN-4 connector
Maximum of three ADB devices recommended
Maximum current draw: 500 mA
(Mouse draws 10 mA, keyboard draws 25 mA)

Specifications I/O Interfaces - 7

Sound

Processor Direct Slot

Sound-input, external microphone port, 8-bit monaural sound,

sampled at 22 or 11 kHz

Monophonic sound-output jack for external audio amplifier or

headphones

Macintosh LC-compatible, 96-pin PDS expansion connector

Specifications I/O Devices - 8

I/O Devices

Keyboard

Mouse

Microphone

Speaker

Standard 80-key Apple keyboard with numeric keypad; ADB

connector

Soft power-on switch

2.5 mm travel, 18 mm vertical and horizontal pitch
Two-level tilt adjustment

Apple Desktop Bus Mouse II
New, ergonomic design

Built-in electret, omnidirectional microphone

Adjustable sound control on front of bezel

Specifications Sound and Video - 9

Sound and Video

Sound Generator

VRAM

Video Display

Monophonic 8-bit digital-analog conversion using 22 KHz

sampling rate for sound input (capable of driving stereo
headphones or other stereo equipment through the sound jack)

Standard: 256K of VRAM on board; displays up to 256 colors;

Supports 1, 2, 4, or 8 bits per pixel

Enhanced: 512K of VRAM; displays up to 32,000 colors; Supports

1, 2, 4, 8, or 16 bits per pixel

Built-in, 10-in. diagonal (254 mm), 9-in. viewable (228 mm)

screen
Trinitron CRT
512 pixels by 384 lines; 76 dpi
Adjustable contrast control on front bezel

Specifications Electrical - 10

Electrical

Line V oltage

Frequency

Maximum Power

90–240 VAC; Universal power supply

47–63 Hz, single phase

100 W

Specifications Physical - 11

Physical

Dimensions

Weight

Height: 14.5 in. (37.0 cm)
Width: 9.9 in. (25.2 cm)
Depth: 12.6 in. (32.15 cm)

22.5–23.2 lb. (10.2–10.5 kg)

Specifications Environmental - 12

Environmental

Operating Temperature

Storage Temperature

Relative Humidity

Altitude

50–104° F (10–40° C)

-40 to 116° F (-40 to 47° C)

20–95% noncondensing

0–15,000 ft. (0–4722 m)

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Service Source

Troubleshooting

Macintosh Color Classic II/

Performa 275

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/Video - 2

Symptom Charts

Video

Screen is black, too
dark, or too bright;
audio and drive
operate

Screen is bright and
audio is present, but
no video information
is visible

1 Adjust contrast button on front bezel.
2 Adjust brightness. Use Brightness Control Panel.
3 Check yoke cable connection.
4 Perform video adjustments. Refer to “Video” in Adjustments

chapter.
5 Replace analog board.
6 Replace CRT.

1 Perform video adjustments. Refer to “Video” in Adjustments

chapter.
2 Replace analog board.
3 Replace CRT.

Troubleshooting Symptom Charts/Video

(Continued)

- 3

Single vertical or
horizontal line is
displayed

Predominant color
tint or color cannot be
adjusted

Video

1 Replace analog board.
2 Replace CRT.

1 Perform video adjustments. Refer to “Video” in Adjustments

2 Replace analog board.
3 Replace CRT if red, green, or blue cannot be turned off using

(Continued)

chapter.

appropriate controls.

Troubleshooting Symptom Charts/Video

(Continued)

- 4

Picture breaks into
diagonal lines, or
picture rolls
vertically or
horizontally

Out of convergence
(color bleeds from
text or lines)

Black screen spots
(burnt phosphors)

Video

Replace analog board.

1 Perform convergence adjustment. Refer to “Convergence” in

2 Replace analog board.
3 Replace CRT.

Replace CRT.

(Continued)

Adjustments chapter.

Troubleshooting Symptom Charts/Video

(Continued)

- 5

Video

Screen jitters or
flashes

Out of focus 1 Perform focus adjustment. Refer to “Focus” in Adjustments

1 Verify that adjacent computer equipment is properly

2 Check that all ground cables are secure.
3 Replace analog board.

2 Replace analog board.
3 Replace CRT only if one part of display remains out of focus

(Continued)

grounded. Move electrical devices away from monitor.

Temporarily shut off all fluorescent lights in area.

chapter.

despite adjustment of focus controls to their limits.

Troubleshooting Symptom Charts/Video

(Continued)

- 6

Flashing or wavy
screen or monitor
emits high-pitched
noise

Raster size too short/
tall or narrow/wide

Linearity bad (size of
text/graphics differs
at top, bottom, or
sides of screen)

Video

Replace analog board.

1 Adjust horizontal or vertical size control. Refer to

2 Replace analog board.

Replace analog board.

(Continued)

Adjustments chapter.

Troubleshooting Symptom Charts/Video

(Continued)

- 7

Raster tilted or
shifted

Video

1 Verify that distortion is not due to environmental conditions

2 Perform appropriate geometric adjustments.
3 Perform yoke adjustment. Refer to “Yoke” in Adjustments

4 Replace analog board.

(Continued)

(move monitor to different location). Refer to “Monitor

Distortion” in Basics chapter of any large-screen monitor

manual.

chapter.

Troubleshooting Symptom Charts/Video

(Continued)

- 8

Video

Raster distorted
(barrel-shaped,
corners not square,
stretched or
compressed at top of
display, or sides not
perpendicular)

Raster not centered 1 Verify that distortion is not due to environmental conditions

1 Verify that distortion is not due to environmental conditions

2 Perform appropriate geometric adjustments.
3 Replace analog board.
4 Replace CRT (only in rare instances).

2 Adjust horizontal or vertical center control. Refer to

3 Replace analog board.

(Continued)

(move monitor to different location). Refer to “Monitor

Distortion” in Basics chapter of any large-screen monitor

manual.

(move monitor to different location). Refer to “Monitor

Distortion” in Basics chapter of any large-screen monitor

manual.

Adjustments chapter.

Troubleshooting Symptom Charts/Floppy Drives - 9

Floppy Drives

Audio and video are
present, but internal
floppy drive does not
operate

Disk ejects; display
shows icon with
blinking “X”

1 Replace bad disk with known-good disk.
2 Replace floppy drive.
3 Replace logic board. Retain customer’s SIMMs, math

coprocessor, and PDS card.
4 Replace floppy drive cable. See “Flat-Cable Assembly” in

Take Apart.

1 Replace bad system disk with known-good system disk.
2 Replace floppy drive.
3 Replace logic board. Retain customer’s SIMMs, math

coprocessor, and PDS card.

Troubleshooting Symptom Charts/Floppy Drives

(Continued)

- 10

Floppy Drives

Unable to insert disk
all the way

Does not eject disk 1 Insert opened paper clip into hole beside floppy drive.

1 To eject previously inserted disk, insert opened paper clip

into hole beside floppy drive.
2 Switch off system and hold mouse button down while

switching system on (to complete eject cycle).
3 Replace floppy drive.

2 Switch off system and hold mouse button down while

switching system on (to complete eject cycle).
3 Replace floppy drive.

(Continued)

Troubleshooting Symptom Charts/Floppy Drives

(Continued)

- 11

Internal floppy drive
runs continuously

Floppy Drives

1 Replace bad disk with known-good disk.
2 Replace floppy drive.
3 Replace logic board. Retain customer’s SIMMs, math

coprocessor, and PDS card.
4 Replace floppy drive cable. See “Flat-Cable Assembly” in

Take Apart.

(Continued)

Troubleshooting Symptom Charts/Hard Drives - 12

Hard Drives

Internal or external
hard drive does not
operate

Works with internal
or external SCSI
device but does not
work with both

1 Verify that SCSI loopback card is not attached.
2 Verify that internal hard drive has all three terminating

resistor packs on circuit board.
3 Verify that external drive is properly terminated.
4 Replace hard drive.
5 Replace logic board. Retain customer’s SIMMs, math

coprocessor, and PDS card.
6 Replace hard drive data cable. See “Flat-Cable Assembly” in

Take Apart.

1 Verify that SCSI device ID switch setting on external device

is higher than 0. Also verify that ID switch setting on

external SCSI device does not duplicate ID switch settings on

any other attached external SCSI devices.
2 Replace terminator on external SCSI device.
3 Replace SCSI select cable.

Troubleshooting Symptom Charts/Peripheral - 13

Peripheral

Cursor does not move 1 Check mouse connection.

2 If mouse was connected to keyboard, connect it to rear ADB

port instead. If mouse works, replace keyboard.
3 If mouse does not work in any ADB port, replace mouse.
4 Replace logic board. Retain customer’s SIMMs, math

coprocessor, and PDS card.

Cursor moves, but
clicking mouse
button has no effect

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

coprocessor, and PDS card.

Troubleshooting Symptom Charts/Peripheral

(Continued)

- 14

Cannot double-click
to open application,
disk, or server

No response to any
key on keyboard

Peripheral

1 Remove extra system files on hard drive.
2 Clear parameter RAM. Hold down <Command> <Option> <P>

<R> keys during system startup but before “Welcome to

Macintosh” appears.
3 If mouse was connected to keyboard, connect it to rear ADB

port instead. If mouse works, replace keyboard.
4 If mouse does not work in any ADB port, replace mouse.
5 Replace logic board. Retain customer’s SIMMs, math

coprocessor, and PDS card.

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

coprocessor, and PDS card.

(Continued)

Troubleshooting Symptom Charts/Peripheral

(Continued)

- 15

Known-good
ImageWriter or
ImageWriter II does
not print

Known-good
LaserWriter does not
print

Peripheral

1 Make sure that Chooser and Control Panel are set correctly.
2 Replace printer driver and system software with known-

good.
3 Replace printer interface cable.
4 Replace logic board. Retain customer’s SIMMs, math

coprocessor, and PDS card.

1 Make sure that Chooser and Control Panel are set correctly.
2 Replace printer driver and system software with known-

good.
3 Refer to Networking and Communications manual.

(Continued)

Troubleshooting Symptom Charts/Miscellaneous - 16

Miscellaneous

Clicking, chirping,
or thumping sound

Smoke/odor Replace analog board.

No video, no audio, and
no drive operation

1 Verify that logic board power cable is connected at J12 on

logic board.
2 Replace analog board.
3 Replace logic board. Retain customer’s SIMMs, math

coprocessor, and PDS card.

1 Connect power cord.
2 Switch power on.
3 Replace power cord.
4 Replace analog board.
5 Replace logic board. Retain customer’s SIMMs, math

coprocessor, and PDS card.

Troubleshooting Symptom Charts/Miscellaneous

(Continued)

- 17

Miscellaneous

“Sad Macintosh” icon 1 Replace bad disk with known-good disk.

2 Replace RAM SIMMs on logic board.
3 Replace logic board. Retain customer’s SIMMs, math

coprocessor, and PDS card.

Screen shows “Sad
Macintosh” icon and
black vertical lines;
screeching sound

1 Replace RAM SIMMs on logic board.
2 Replace logic board. Retain customer’s SIMMs, math

coprocessor, and PDS card.

(Continued)

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Service Source

T ak e Apart

Macintosh Color Classic II/

Performa 275

Take Apart Logic Board - 1

Logic Board

No preliminary steps are
required before you begin
this procedure.

Logic Board

Caution:

precautions: use a grounded
workbench pad, and always
wear a grounding
wriststrap.

Follow proper ESD

Take Apart Logic Board - 2

1 If necessary, remove

the two security screws
from the I/O door.

2 Push down the two

latches until the I/O door
snaps open. Remove the
door from the rear
housing.

I/O Door

Take Apart Logic Board - 3

3 Grasp the logic board

firmly with both hands
and pull it straight out of
the chassis. Place the
logic board on a grounded
workbench pad.

Logic Board

Take Apart Logic Board - 4

Replacement Note:

are replacing a defective
logic board, remove the RAM
and VRAM SIMMs (if
installed), 68882 math
coprocessor, and PDS card.
Install these components on
the replacement logic board.

Replacement Caution:

reconnecting the logic board,
make sure there are no bent
metal tabs on the chassis
that could contact the
bottom of the logic board and
short out the board.

If you

After

Take Apart Rear Housing - 5

Rear Housing

Rear Housing

No preliminary steps are
required before you begin
this procedure.

±

Warning:

contains high voltage and a
high-vacuum picture tube.
To prevent injury, review
CRT safety and discharge
instructions in Bulletins/
Safety.

This product

Take Apart Rear Housing - 6

1 Using a long-handled

Torx screwdriver,
remove the four case
screws. If necessary,
remove the two security
screws from the I/O
door.

2 Using a case spreader

(pull-apart tool),
separate the housing
from the chassis.
Carefully lift the rear
housing and set it aside.

Take Apart Rear Housing - 7

±

Warning:

the metal chassis may be
sharp. When moving the
computer with the rear
housing off, be sure to
handle the chassis carefully.

The edges of

Replacement Note:

are replacing a damaged rear
housing, first remove the
fan (see the “Fan” topic in
this chapter).

If you

Take Apart Analog Board - 8

Analog Board

Before you begin,

• Remove the rear housing

• Discharge the CRT

• Remove the anode cap

±

Analog Board

Warning:

contains high voltage and a
high-vacuum picture tube.
To prevent injury, review
CRT safety and discharge
instructions in Bulletins/
Safety.

±

Warning:

grounding wriststrap until
after discharging the CRT.

This product

Never use a

Take Apart Analog Board - 9

1 Unhook the video board

ground wire from the
CRT grounding strap.

Ground Wire

Replacement Caution:

When
replacing the analog board,
be sure to securely
reconnect the ground wire to
the CRT grounding strap.
Switching on system power
without reconnecting the
ground strap could damage
components.

Take Apart Analog Board - 10

2

Note:

If sealant holds
the video board in place,
cut the sealant with an
art knife.

Carefully pull the video
board straight off the

Video
Board

neck of the CRT.

Take Apart Analog Board - 11

3 Using a flat-blade

screwdriver, release the

Degauss Cable

connector latch and
disconnect the degauss
cable from analog board
connector BP2.

Microphone Cable

4 Disconnect the yoke

cable from analog board
connector BD1.

5 Disconnect the two

halves of the microphone

Yoke Cable

cable.

Take Apart Analog Board - 12

6

Note:

When removing
the analog board in this
step, be careful not to
damage the speaker cable
that is connected
beneath the analog board.

Pull out the analog
board approximately two
inches and align the edge
of the board with
cutouts in the plastic

Chassis

guide.

7 Lift out the analog board

Analog
Board

and place it on the
workbench pad.

Take Apart Analog Board - 13

8 Disconnect the two

halves of the speaker
cable that are located
beneath the analog board.

9 Place the analog board on

a grounded workbench

Speaker Cable

pad.

Take Apart Speaker - 14

Speaker

Before you begin,

• Remove the rear housing

• Discharge the CRT

• Remove the anode cap

• Remove the analog board

±

Warning:

contains high voltage and a
high-vacuum picture tube.
To prevent injury, review
CRT safety and discharge
instructions in Bulletins/
Safety.

Speaker

This product

Take Apart Speaker - 15

±

Warning:

grounding wriststrap until
after discharging the CRT.

Remove the speaker from
the two hook loop fasteners
on the chassis.

Speaker

Never use a

Take Apart Floppy Drive - 16

Floppy Drive

Before you begin,

• Remove the rear housing

• Discharge the CRT

• Remove the anode cap

• Remove the analog board

• Remove the speaker

±

Floppy Drive

Warning:

contains high voltage and a
high-vacuum picture tube.
To prevent injury, review
CRT safety and discharge
instructions in Bulletins/
Safety.

This product

Take Apart Floppy Drive - 17

±

Floppy Drive

Floppy Drive

Cable

Warning:

grounding wriststrap until
after discharging the CRT.

1 Disconnect the floppy

drive cable and push it
through the hole in the
plastic chassis.

2 Depress the mounting

tab and pull the floppy
drive straight out of the
chassis mounting
channel.

Note:

may catch beneath the
front of the drive
mount. If this happens,
tug the drive straight

Never use a

The mounting tab

Take Apart Floppy Drive - 18

back and it will pop over
the tab.

Shield

Plastic Carrier

Replacement Note:

If you
are replacing a defective
floppy drive, remove the
four carrier mounting
screws and separate the
drive from the plastic
carrier. Remove the shield
from the drive mechanism.

Take Apart Hard Drive - 19

Hard Drive

Before you begin,

• Remove the rear housing

• Discharge the CRT

• Remove the anode cap

• Remove the analog board

Hard Drive

±

Warning:

contains high voltage and a
high-vacuum picture tube.

Hard Drive

To prevent injury, review

Power Cable

CRT safety and discharge
instructions in Bulletins/
Safety.

This product

Take Apart Hard Drive - 20

±

Hard Drive

Data Cable

Hard Drive

Warning:

grounding wriststrap until
after discharging the CRT.

1 Disconnect the hard

drive data and hard drive
power cables.

2 Push the cables through

the hole in the plastic
chassis.

Never use a

Take Apart Hard Drive - 21

3 Raise the mounting tab

and pull the hard drive
straight out of the
chassis mounting
channel.

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 Chassis - 22

Chassis

Chassis

Before you begin,

• Remove the rear housing

• Discharge the CRT

• Remove the anode cap

• Remove the analog board

±

Warning:

contains high voltage and a
high-vacuum picture tube.
To prevent injury, review
CRT safety and discharge
instructions in Bulletins/
Safety.

This product

Take Apart Chassis - 23

±

Bezel

Chassis

Warning:

grounding wriststrap until
after discharging the CRT.

1 Open the two release tabs

on one side of the chassis
and raise that side of the
chassis.

2 To keep the side of the

chassis raised, insert a
small flat-blade
screwdriver between the
chassis and the bezel.

Never use a

Take Apart Chassis - 24

3 Using a small flat-blade

screwdriver, pry open
the two release tabs on
the other side of the
chassis and raise the
chassis.

4 Lift the chassis straight

Chassis

out of the bezel.

Replacement Note:

If you
are replacing a damaged
chassis, first remove the
speaker, floppy drive, hard
drive, logic board, push­button board, and flat-cable
assembly. Refer to the
appropriate topics in this
chapter.

Take Apart Pushbutton Board - 25

Pushbutton Board

Before you begin,

• Remove the rear housing

• Discharge the CRT

• Remove the anode cap

• Remove the analog board

• Remove the chassis

±

Pushbutton Board

Warning:

contains high voltage and a
high-vacuum picture tube.
To prevent injury, review
CRT safety and discharge
instructions in Bulletins/
Safety.

±

Warning:

This product

Never use a

Take Apart Pushbutton Board - 26

grounding wriststrap until
after discharging the CRT.

1 Raise and push out the

mounting tabs along
both sides of the bottom
shield.

Chassis

2 Remove the bottom

shield from the chassis.

3 Set the shield aside.

Mounting
Tabs

Cable
Metal
Tabs

Bottom Shield

Replacement Caution:

replacing the bottom shield
on the chassis, make sure
none of the metal tabs along
the bottom (rear) edge of
the shield is bent up (toward
the logic board). Bent tabs

When

Take Apart Pushbutton Board - 27

could contact and short out
the logic board.

4 Using a T-8 Torx

driver, remove the two
screws that secure the
pushbutton board to the

Push-Button Board

chassis.

5 Disconnect the push-

button board from the
cable connector.

Connector

Replacement Note:

Reconnect the cable to the
pushbutton board before
reinstalling the board on
the chassis.

Take Apart Flat-Cable Assembly - 28

Flat-Cable Assembly

Before you begin,

• Remove the rear housing

• Discharge the CRT

• Remove the anode cap

• Remove the analog board

• Remove the chassis

• Remove the logic board

• Remove the speaker

• Remove the floppy drive

• Remove the hard drive

• Remove the pushbutton

Flat-Cable
Assembly

board

Take Apart Flat-Cable Assembly - 29

±

Warning:

contains high voltage and a
high-vacuum picture tube.
To prevent injury, review
CRT safety and discharge
instructions in Bulletins/
Safety.

This product

Small
Connector
Bridge

Analog
Board
Cables

1 Release the plastic latch

and remove the small
connector bridge (to the
analog board) from the
chassis.

2 Turn over the chassis.

3 Push the analog board

cables and small
connector bridge

Take Apart Flat-Cable Assembly - 30

through the access hole
in the chassis.

4 Release the three plastic

latches and remove the
large connector bridge

Large Connector
Bridge

(to the logic board) from
the chassis.

5 Remove the drive cables

from the plastic cable
retainers, and remove
the flat-cable assembly.

Replacement Note:

The
plastic cable retainers on
the chassis fit the width of
the drive cables.

Take Apart Microphone Assembly - 31

Microphone Assembly

Before you begin,

• Remove the rear housing

• Discharge the CRT

• Remove the anode cap

±Warning: This product

contains high voltage and a
high-vacuum picture tube.
To prevent injury, review
CRT safety and discharge
instructions in Bulletins/
Safety.

Microphone
Assembly

Take Apart Microphone Assembly - 32

±Warning: Never use a

grounding wriststrap until
after discharging the CRT.

1 Disconnect the

microphone cable
between the microphone
and the analog board.

Microphone Cable

2 If necessary, cut the tie-

wrap that secures the
microphone cable to the
degauss coil.

Take Apart Microphone Assembly - 33

Microphone Assembly

3 Open the two plastic

latches and remove the
microphone assembly
from the bezel.

Replacement Note: You may
need to use a flat-blade
screwdriver to press the
microphone gasket back into
the chassis.

Bezel

Take Apart CRT - 34

CRT

Before you begin,

• Remove the rear housing

• Discharge the CRT

• Remove the anode cap

• Remove the analog board

CRT

• Disconnect the

microphone cable

±Warning: This product

contains high voltage and a
high-vacuum picture tube.
To prevent injury, review
CRT safety and discharge
instructions in Bulletins/
Safety.

Take Apart CRT - 35

±Warning: Never use a

grounding wriststrap until
after discharging the CRT.

1 Remove the four self-

threading screws that
secure the CRT to the
bezel.

2 ±Warning: Never

touch the anode or grasp
the neck of the CRT to
remove it from the
bezel. The neck of the
CRT breaks easily and
the anode may retain
high voltages.

Lift the CRT straight out
of the bezel and place the

Take Apart CRT - 36

CRT facedown on the
protective workbench
pad.

±Warning: If you need to

dispose of the CRT, refer to
CRT disposal instructions in
Bulletins/Safety.

Replacement Note: If you
are replacing a defective
CRT, first remove the
degauss coil (see the next
topic).

Take Apart Degauss Coil - 37

Degauss Coil

Before you begin,

• Remove the rear housing

• Discharge the CRT

• Remove the anode cap

• Remove the analog board

• Disconnect the

microphone cable

• Remove the CRT

±Warning: This product

contains high voltage and a
high-vacuum picture tube.
To prevent injury, review

Degauss Coil

CRT safety and discharge
instructions in Bulletins/
Safety.

Take Apart Degauss Coil - 38

±Warning: Never use a

grounding wriststrap until
after discharging the CRT.

1 Remove the degauss coil

Ground Strap

cable from the tie-wrap
at the side of the CRT
yoke.

2 Lift the degauss coil with

attached brackets over
the neck of the CRT.

Replacement Note: When
replacing the degauss coil,
be sure to reattach the
ground strap to the degauss
bracket.

Take Apart Bezel - 39

Bezel

To remove the bezel,

Bezel

• Remove the rear housing

• Discharge the CRT

• Remove the anode cap

• Remove the analog board

• Remove the chassis

• Remove the microphone

assembly

• Remove the CRT

Take Apart Fan - 40

Fan

Before you begin, remove
the rear housing.

Fan

Take Apart Fan - 41

Open the two latches and pull
the fan straight out of the

Rear Housing

Fan

rear housing.

K

Service Source

Upgrades

Macintosh Color Classic II/

Performa 275

Upgrades VRAM Upgrade - 1

VRAM Upgrade

VRAM SIMM

Before you begin, remove
the logic board.

Caution:

precautions in Bulletins/
Safety.

Review the ESD

Upgrades VRAM Upgrade - 2

Note:

The Color Classic II/
Performa 275 has 256K of
video RAM (VRAM) soldered
on the logic board. You can
increase the amount of VRAM
to 512K by installing a
256K VRAM SIMM in the
SIMM slot (connector J9).
Use only 100 ns or faster
VRAM SIMMs.

Upgrades VRAM Upgrade - 3

1 Grasp the VRAM SIMM

by its edges with the
contacts pointing down.

J9 SIMM Slot

Insert the SIMM at an
angle into SIMM slot J9.

2 Push back on the SIMM

VRAM SIMM

until it snaps into place.

Upgrades Math Coprocessor - 4

Math Coprocessor

Before you begin, remove
the logic board.

Math

Coprocessor

Caution:

precautions in Bulletins/
Safety.

You can add a Motorola
68882 math coprocessor to
the logic board in the Color
Classic II/Performa 275,
thereby increasing overall
system performance.

Review the ESD

Upgrades Math Coprocessor - 5

1 Position the math

Math Coprocessor

J13 Connector

coprocessor over socket
U9 with the beveled edge
of the chip toward the
large contact connector
(J13) at the front of the
board.

2 Align the pins in the

socket and gently press
down the chip.

Beveled
Edge

Upgrades Memory Upgrade - 6

Memory Upgrade

RAM SIMMs

Before you begin, remove
the logic board.

Caution:

precautions in Bulletins/
Safety.

Note:

Performa 275 has 4 MB of
RAM soldered on the logic
board which can be
expanded to 10 MB of RAM.
The Color Classic II/
Performa 275 includes one
SIMM expansion slot with
two 30-pin connectors. The

Review the ESD

The Color Classic II/

Upgrades Memory Upgrade - 7

system requires 100 ns or
faster RAM SIMMs. For
additional information,
refer to Hardware/Memory.

1

Note:

Both connectors in

the J10 SIMM slot must

RAM SIMM

be filled or both must be
empty; you cannot
install a SIMM into just
one of the two slots.

Grasp the RAM SIMMs by
the edges with the
contacts pointing down.
Insert the SIMMs at an

J10 SIMM Connectors

angle into the J10
connectors.

Upgrades Memory Upgrade - 8

2 Push back on the SIMMs

until they snap into
place.

Upgrades PDS Upgrades - 9

PDS Upgrades

Before you begin, remove
the logic board.

Note:

The 96-pin processor
direct slot in the Color
Classic II/Performa 275 is
compatible with the PDS slot
in the Macintosh LC.
Currently Apple offers two
PDS expansion cards for the
Macintosh LC and Color
Classic series: the Apple IIe
emulation card and the LC
Ethernet card.

PDS Card

Upgrades PDS Upgrades - 10

Rear Housing

Lock Plate

Caution:

Review the ESD
precautions in Bulletins/
Safety.

1 Squeeze together the

latches and pull the lock
plate off the inside of the
access cover.

2 Remove the access cover

from the rear housing.

Upgrades PDS Upgrades - 11

3 Connect the expansion

card to the 96-pin PDS
connector (J8) on the
logic board.

J8 PDS Connector

K

Service Source

Additional Procedures

Macintosh Color Classic II/

Performa 275

Additional Procedures Battery Verification - 1

Battery Verification

Before you begin, remove
the logic board.

±

Battery

Warning:

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

If handled or

Caution:

precautions in Bulletins/
Safety.

Review the ESD

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

Negative
Probe

battery and the negative
probe to the negative
end of the battery.

Positive
Probe

3 If the battery voltage is

below 3.0 volts, replace
the battery. Refer to
“Battery Replacement”
in this chapter.

Additional Procedures Battery Replacement - 3

Battery Replacement

Before you begin, remove
the logic board.

±

Battery

Warning:

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

If handled or

Caution:

precautions in Bulletins/
Safety.

Review the ESD

Additional Procedures Battery Replacement - 4

1 Insert a small flat-

blade screwdriver into
the top of the battery
holder cover and gently
push down and out with

Cover

the screwdriver to
release the tab.

2 Repeat on the other end

and remove the cover

Battery
Holder

from the battery holder.

Additional Procedures Battery Replacement - 5

3 Grasp the battery and

remove it from the
holder.

4 Return the battery to

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

K

Service Source

Adjustments

Macintosh Color Classic II/

Performa 275

Adjustments Geometry - 1

Geometry

Before you begin, remove
the rear housing.

±

Warning:

contains high voltage and a
high-vacuum picture tube.
To prevent injury, review
the CRT safety instructions
in Bulletins/Safety.

This product

Adjustment

Controls

Logic Board

Chassis

Adjustment
Controls

Warning:

High Voltage

Areas

Support

Adjustments Geometry - 2

Note:

The controls on this
monitor require a short
hex-head plastic tool to
make adjustments. If the tool
is long or too thin, it will be
too flexible, which will
make fine adjustments
difficult. Use a short, rigid,
hex-head plastic tool to
minimize flexing.

±

Warning:

metal alignment tools—they
are a shock hazard.

1

Caution:

housing removed, the
metal chassis could short
to the bottom of the logic

Do not use

With the rear

Adjustments Geometry - 3

board. Before switching
on system power, make
sure the chassis is not
touching the logic board.

All-White Screen

To prevent the bottom of
the chassis from
buckling and touching
the logic board, you may
want to support the rear
corners of the chassis.

Switch on system power.

2 Using Display Service

Utility from the Utilities
folder of the MacTest Pro
CD, display the All­White Screen test
pattern.

Adjustments Geometry - 4

Vertical Center

Using a hex-head plastic
adjustment tool, adjust the

All-White Screen

Vertical Center

vertical center control
until the raster is centered
(top to bottom) in the
display area.

Adjustments Geometry - 5

Horizontal Center

Using a hex-head plastic
adjustment tool, adjust the

All-White Screen

Horizontal
Center

horizontal center control
until the raster is centered
(side to side) in the display
area.