Apple Macintosh 575 Service Manual

Name: Apple Macintosh 575
Brand: Apple
SKU: 1186510
Rating: 5 (1 reviews)

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Macintosh LC 520/550/575

Macintosh LC 520, Macintosh LC 550,

Macintosh LC 575

Service Source

Basics

Macintosh LC 520, 550, 575

Basics	Overview - 1

Overview

This manual includes complete repair procedures for the LC 520, LC 550, and LC 575, shown at left.

Figure: Macintosh LC 520, LC 550, LC 575

Basics	Product Information - 2

Product Information

Identifying Features

The LC 575 logic board includes a 68LC040 processor, an additional communications slot, and a new hook-and-loop- attached battery. The LC 520 and LC 550 do not include these features.

The LC 550 and LC 575 ship with

• the newer manual-inject 1.4 MB Apple SuperDrive and require the keyhole-shaped bezel.

• a revised chassis harness assembly that does not use a floppy drive adapter

• the newer, caddyless CD 300+ CD ROM drive

Basics	Product Information - 3

Compatibility Notes

You can exchange the chassis harness assembly of the LC 520 or LC 550 with the newer chassis harness assembly of the LC 575. The newer chassis harness assembly requires the manual-inject floppy drive and caddyless CD ROM drive.

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Speciﬁcations

Macintosh LC 520, 550, 575

	Specifications	Processor - 1

		Processor
LC 520		Motorola 68030 microprocessor
		25 MHz
		Built-in memory management unit (MMU)
LC 550		Motorola 68030 microprocessor
		33 MHz
		Built-in MMU

LC 575

Coprocessor

Motorola 68LC040 microprocessor 33 MHz

Built-in MMU

Socket for optional math coprocessor

Specifications	Memory - 2

RAM

ROM

PRAM

Memory

4 MB of dynamic RAM on board

Expandable to 36 MB (100 ns or faster SIMMs) 72-pin DRAM SIMM connector

1 MB of ROM

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

	Specifications	Memory - 3

VRAM		512K of VRAM on board (displays up to 256 colors or 8-bit
		color)
		Expandable to I MB (displays up to 32,000 colors or 16-bit
		color)
		68-pin VRAM SIMM connector (LC 520)
		Two VRAM SIMM slots (LC 575)

Specifications	Disk Storage - 4

Floppy Drive

Hard Drive

CD-ROM Drive

Disk Storage

Internal 1.4 MB Apple SuperDrive, auto-inject (LC 520) Internal 1.4 MB Apple SuperDrive, manual-inject (LC 550 and

LC 575)

3.5-inch, internal 80, 160, 250, or 320 MB SCSI hard drive

Internal Apple CD 300i CD-ROM drive (LC 520)

Internal Apple CD 300+ CD-ROM drive (LC 550 and LC 575)

Specifications	I/O Interfaces - 5

Serial

SCSI

Apple Desktop Bus

Processor-Direct Slot

I/O Interfaces

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 Apple Desktop Bus (ADB) ports; mini DIN-4 connectors Maximum of three ADB devices recommended

Maximum current draw: 500 mA (Mouse draws 10 mA; keyboard draws 25 mA.)

Internal expansion slot for 96 or 114-pin processor-direct expansion cards

	Specifications	I/O Interfaces - 6

Communications		Internal expansion for 50-pin modem and Ethernet cards
Slot (LC 575)
Sound		Sound-output port capable of delivering stereo sound
		Sound-input port for monaural sound input
		Front headphone jack capable of delivering stereo sound

	Specifications	I/O Devices - 7

		I/O Devices
Keyboard		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

Mouse

Microphone

Speaker

Apple Desktop Bus Mouse II

New, ergonomic design

Built-in electret, omnidirectional microphone Adjustable sound control on front of bezel

Specifications	Sound and Video - 8

Sound Generator

Video Display

Sound and Video

Records at 11 kHz or 22 kHz sample rate

Plays back at 22 kHz sample rate

Two speakers with enhanced stereo sound

Allows playback and recording of ordinary audio compact discs

14-in. diagonal, 13-in. viewable screen Trinitron CRT with high-contrast glass

.26-mm aperture grille pitch

640 pixels by 480 lines; 70 dpi

Specifications	Electrical - 9

Electrical

Line Voltage

Frequency

Maximum Power

100–240 VAC; Universal power supply

47–63 Hz, single phase

120 W

	Specifications	Physical - 10

		Physical
Dimensions		Height: 17.9 in. (45.5 cm)
		Width: 13.5 in. (34.4 cm)
		Depth: 16.5 in. (42.0 cm)
Weight		40.5 lb. (18.4 kg)

	Specifications	Environmental - 11

		Environmental
Operating		50–104° F (10–40° C)
Temperature
Storage		-40 to 149° F (-40 to 65° C)
Temperature
Relative Humidity		20–95% noncondensing
Altitude		0–10,000 ft. (operating)

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Troubleshooting

Macintosh LC 520, 550, 575

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		1	Adjust contrast button on front bezel.
dark, or too bright;		2	Adjust brightness. Use Screen Control Panel.
audio and drive		3	Check yoke cable connection.
operate		4	Perform video adjustments. Refer to “Video” in Adjustments
			chapter.
		5	Perform battery verification.
		6	Replace analog board.
		7	Replace CRT.
Screen is bright and		1	Perform video adjustments. Refer to “Video” in Adjustments
audio is present, but			chapter.
no video information		2	Replace analog board.
is visible		3	Replace CRT.

	Troubleshooting		Symptom Charts/Video (Continued) - 3

		Video (Continued)

Single vertical or		Note: A thin, gray, horizontal line may be visible across the
horizontal line is		bottom third of a lit screen. This line is inherent in the design of
displayed		Trinitron monitors. Do not replace modules.
		Otherwise,
		1	Replace analog board.
		2	Replace CRT.
Predominant color		1	Perform video adjustments. Refer to “Video” in Adjustments
tint or color cannot be			chapter.
adjusted		2	Replace analog board.
		3	Replace CRT if red, green, or blue cannot be turned off using
			appropriate controls.
Black screen spots		Replace CRT.
(burnt phosphors)

	Troubleshooting		Symptom Charts/Video (Continued) - 4

		Video (Continued)

Picture breaks into		1	Perform video adjustments. Refer to “Video” in Adjustments
diagonal lines, or			chapter.
picture rolls		2	Replace analog board.
vertically or
horizontally
Out of convergence		1	Perform convergence adjustment. Refer to “Convergence” in
(color bleeds from			Adjustments chapter.
text or lines)		2	Replace analog board.
		3	Replace CRT.
Flashing or wavy		Replace analog board.
screen or monitor
emits high-pitched
noise


	Troubleshooting		Symptom Charts/Video (Continued) - 5

		Video (Continued)
		Video (Continued)
Screen jitters or		1	Verify that adjacent computer equipment is properly
flashes			grounded. Move electrical devices away from monitor.
			Temporarily shut off all fluorescent lights in area.
		2	Check that all ground cables are secure.
		3	Disconnect internal floppy drive, CD-ROM drive, and hard
			drive.
		4	Replace analog board.
Out of focus		1	Perform focus adjustment. Refer to “Focus” in Adjustments.
		2	Replace analog board.
		3	Replace CRT only if one part of display remains out of focus
			despite adjustment of focus controls to their limits.
Raster size too short/		1	Adjust horizontal or vertical size control. Refer to
tall or narrow/wide			Adjustments chapter.
		2	Replace analog board.

	Troubleshooting		Symptom Charts/Video (Continued) - 6

		Video (Continued)

Linearity bad (size of		1	Perform video adjustments. Refer to “Video” in Adjustments
text/graphics differs			chapter.
at top, bottom, or		2	Replace analog board.
sides of screen)
Raster tilted or		1	Verify that adjacent computer equipment is properly
shifted			grounded. Move electrical devices away from monitor.
			Temporarily shut off all fluorescent lights in area.
		2	Perform appropriate geometric adjustments. Refer to
			Adjustments chapter.
		3	Perform yoke adjustment. Refer to “Yoke” in Adjustments
			chapter.
		4	Replace analog board.

	Troubleshooting		Symptom Charts/Video (Continued) - 7

		Video (Continued)
Raster not centered		1	Verify that adjacent computer equipment is properly
			grounded. Move electrical devices away from monitor.
			Temporarily shut off all fluorescent lights in area.
		2	Adjust horizontal or vertical center control. Refer to
			Adjustments chapter.
		3	Replace analog board.
Raster distorted		1	Verify that adjacent computer equipment is properly
(barrel-shaped,			grounded. Move electrical devices away from monitor.
corners not square,			Temporarily shut off all fluorescent lights in area.
stretched or		2	Perform appropriate geometric adjustments. Refer to
compressed at top of			Adjustments chapter.
display, or sides not		3	Replace analog board.
perpendicular)		4	Replace CRT (only in rare instances).

Troubleshooting Symptom Charts/Floppy Drive - 8