Apple color classic Service Manual

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Macintosh Color Classic

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Basics

Macintosh Color Classic

Basics	Overview - 1

Overview

This manual contains complete repair procedures for the Macintosh Color Classic shown at left.

Figure: Macintosh Color Classic

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Specifications

Color Classic

	Specifications	Configurations - 1
		Configurations
Standard		4 MB RAM, 256K VRAM, 3.5-in. hard drive (many sizes),
		internal 1.4 MB floppy drive, user-removable logic board, 9-
		in. color display, built-in speaker and microphone, keyboard,
		mouse, ADB and power cables, system software installed on
		hard drive (requires System 7.1)
Options		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		Motorola 68030 microprocessor
		16 MHz
		Built-in Paged Memory Management Unit (PMMU)
		256-byte instruction and data caches

Coprocessor

Addressing

Socket for optional Motorola 68882 floating-point coprocessor 16 MHz

16-bit data bus

32-bit address bus

16-bit internal registers

Specifications	Memory - 3

RAM

ROM

PRAM

Memory

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

Serial

SCSI

Apple Desktop Bus

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 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		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
Processor Direct Slot		Macintosh LC-compatible, 96-pin PDS expansion connector

Specifications	I/O Devices - 8

Keyboard

Mouse

Microphone

Speaker

I/O Devices

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

Built-in electret, omnidirectional microphone

Adjustable sound control on front of bezel

Specifications	Sound and Video - 9

Sound and Video

Sound Generator

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)

VRAM	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

	Specifications	Sound and Video - 10
Video Display		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 - 11

Electrical

Line Voltage

Frequency

Maximum Power

90–240 VAC; Universal power supply

47–63 Hz, single phase

100 W

	Specifications	Physical - 12
		Physical
Dimensions		Height: 14.5 in. (37.0 cm)
		Width: 9.9 in. (25.2 cm)
		Depth: 12.6 in. (32.15 cm)
Weight		22.5–23.2 lb. (10.2–10.5 kg)

	Specifications	Environmental - 13
		Environmental
Operating		50–104° F (10–40° C)
Temperature
Storage		-40 to 116° F (-40 to 47° C)
Temperature
Relative Humidity		20–95% noncondensing
Altitude		0–15,000 ft. (0–4722 m)

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Troubleshooting

Color Classic

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 - 2

Symptom Charts

Video

Screen is black, too	1	Adjust contrast button on front bezel.
dark, or too bright;	2	Reset PRAM.
audio and drive	3	Check yoke cable connection.
operate	4	Perform video adjustments. Refer to “Video” in Adjustments
		chapter.
	5	Replace analog board.
	6	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 - 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.

	Troubleshooting		Symptom Charts - 4
		Video (Continued)
Picture breaks into		Replace analog board.
diagonal lines, or
picture rolls
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.
Black screen spots		Replace CRT.
(burnt phosphors)

	Troubleshooting		Symptom Charts - 5
		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 hard drive and floppy drive.
		4	Replace analog board.
Out of focus		1	Perform focus adjustment. Refer to “Focus” in Adjustments
			chapter.
		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.

	Troubleshooting	Symptom Charts - 6
		Video (Continued)
Flashing or wavy		Replace analog board.
screen or monitor
emits high-pitched
noise
Raster size too short/		1 Adjust horizontal or vertical size control. Refer to
tall or narrow/wide		Adjustments chapter.
		2 Replace analog board.
Linearity bad (size of		Replace analog board.
text/graphics differs
at top, bottom, or
sides of screen)

	Troubleshooting		Symptom Charts - 7
		Video (Continued)
Raster tilted or		1	Verify that distortion is not due to environmental conditions
shifted			(move monitor to different location). Refer to “Monitor
			Distortion” in Basics chapter of any large-screen monitor
			manual.
		2	Perform appropriate geometric adjustments.
		3	Perform yoke adjustment. Refer to “Yoke” in Adjustments
			chapter.
		4	Replace analog board.

	Troubleshooting		Symptom Charts/Video (Continued) - 8
		Video (Continued)
Raster distorted		1	Verify that distortion is not due to environmental conditions
(barrel-shaped,			(move monitor to different location). Refer to “Monitor
corners not square,			Distortion” in Basics chapter of any large-screen monitor
stretched or			manual.
compressed at top of		2	Perform appropriate geometric adjustments.
display, or sides not		3	Replace analog board.
perpendicular)		4	Replace CRT (only in rare instances).
Raster not centered		1	Verify that distortion is not due to environmental conditions
			(move monitor to different location). Refer to “Monitor
			Distortion” in Basics chapter of any large-screen monitor
			manual.
		2	Adjust horizontal or vertical center control. Refer to
			Adjustments chapter.
		3	Replace analog board.

Troubleshooting Symptom Charts - 9

Floppy Drives

Audio and video are	1	Replace bad disk with known-good disk.
present, but internal	2	Replace floppy drive.
floppy drive does not	3	Replace logic board. Retain customer’s SIMMs, math
operate		coprocessor, and PDS card.
	4	Replace floppy drive cable. See “Flat-Cable Assembly” in
		Take Apart.
Disk ejects; display	1	Replace bad system disk with known-good system disk.
shows icon with	2	Replace floppy drive.
blinking “X”	3	Replace logic board. Retain customer’s SIMMs, math
		coprocessor, and PDS card.

Troubleshooting Symptom Charts - 10

Floppy Drives (Continued)

Unable to insert disk	1	To eject previously inserted disk, insert opened paper clip
all the way		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.
Does not eject disk	1	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.

Troubleshooting Symptom Charts/Floppy Drives (Continued) - 11

Floppy Drives (Continued)

Internal floppy drive	1	Replace bad disk with known-good disk.
runs continuously	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.

Troubleshooting Symptom Charts - 12

Hard Drives

Internal or external	1	Verify that SCSI loopback card is not attached.
hard drive does not	2	Verify that internal hard drive has all three terminating
operate		resistor packs on circuit board.
	3	Verify that external drive is properly terminated.
	4	Replace hard drive data cable. See “Flat-Cable Assembly” in
		Take Apart.
	5	Replace hard drive.
	6	Replace logic board. Retain customer’s SIMMs, math
		coprocessor, and PDS card.