Apple LC 550 Specifications Page 1

Service Source K Macintosh LC 520/550/575 Macintosh LC 520, Macintosh LC 550,Macintosh LC 575

Specifications Disk Storage - 4 Disk Storage Floppy Drive Internal 1.4 MB Apple SuperDrive, auto-inject (LC 520)Internal 1.4 MB Apple SuperDrive, ma

Upgrades Macintosh Processor Upgrade - 2 Note: The Macintosh Processor Upgrade kit allows 68LC040 computers to switch between a PowerPC 601 proces

Upgrades Macintosh Processor Upgrade - 3 Note: The PowerPC upgrade for the Macintosh LC 520 and 550 consists of a Macintosh LC 575 logic board, th

Upgrades Macintosh Processor Upgrade - 4 Note: Refer to the Macintosh Processor Upgrade manual for information about specifications and troublesho

Upgrades Macintosh Processor Upgrade - 5 Note: The Macintosh Processor Upgrade comes packaged with the Macintosh Processor Upgrade board, 256K cac

Upgrades Macintosh Processor Upgrade - 6 Note: The cache card comes installed on the upgrade board.

Upgrades Macintosh Processor Upgrade - 7 Installation Procedure Overview These are the basic steps to installing the Macintosh Processor Upgrade. •

Upgrades Macintosh Processor Upgrade - 8 • Reinstall the cache card on the upgrade boardDetailed procedures follow.

Upgrades Macintosh Processor Upgrade - 9 Remove the 68LC040 Processor from the Logic Board 1 Locate the 68LC040 processor on the logic board.68LC040

Upgrades Macintosh Processor Upgrade - 10 2 Position the teeth of the processor removal tool in the groove between the processor and the logic board

Upgrades Macintosh Processor Upgrade - 11 Note: This graphic shows the proper way to remove a 68LC040 chip from its logic board. Your logic b

Specifications I/O Interfaces - 5 I/O Interfaces Serial Two RS-232/RS-422 serial ports; mini DIN-8 connectors SCSI One SCSI parallel port; DB-25 con

Upgrades Macintosh Processor Upgrade - 12 Install the 68LC040 Processor on the Upgrade Board Note: The alignment corner of the 68LC040 processor i

Upgrades Macintosh Processor Upgrade - 13 Caution: Forcing the 68LC040 processor connector pins into the socket could damage the pins. If the proc

Upgrades Macintosh Processor Upgrade - 14 3 Hold the processor and spacer together and position the spacer alignment corner over the upgrade socket

Upgrades Macintosh Processor Upgrade - 15 Note: On a correctly installed 040 processor, a very small gap separates the 040 chip from the metal spa

Upgrades Macintosh Processor Upgrade - 16 Prepare the Upgrade and Logic Boards for Installation Note: The following steps explain how to prepare t

Upgrades Macintosh Processor Upgrade - 17 Note: You will reinstall the cache card after the upgrade board connects to the logic board. Caution:

Upgrades Macintosh Processor Upgrade - 18 2 Note: This step helps prevent the logic board from bending when you apply pressure in the next few ste

Upgrades Macintosh Processor Upgrade - 19 4 Note: This step makes room for the processor upgrade board.Move the battery from its original hook-and

Upgrades Macintosh Processor Upgrade - 20 Install the Upgrade Board on the Logic Board Caution: Forcing the upgrade board connector pins into the

Upgrades Macintosh Processor Upgrade - 21 2 Carefully align the pins along all sides of the processor and socket.3 Firmly press the connector pins i

Specifications I/O Interfaces - 6 Communications Slot (LC 575) Internal expansion for 50-pin modem and Ethernet cards Sound Sound-output port capabl

Upgrades Macintosh Processor Upgrade - 22 Note: After you install the upgrade board, connect the battery cable through the hole in the upgrade boa

Upgrades Macintosh Processor Upgrade - 23 6 Note: There are two sockets on the cache card. Align the longer cache card socket with the longer row

Upgrades Macintosh Processor Upgrade - 24 Logic Board and Upgrade Board Returns Return the upgrade and logic boards to their original conditions bef

Service Source K Additional Procedures Macintosh LC 520, 550, 575

Additional Procedures Battery Verification, LC 520 - 1 Battery Verification, LC 520 Before you begin, remove the following:• I/O door• Logic board ±

Additional Procedures Battery Verification, LC 520 - 2 Caution: Review the ESD precautions in Bulletins/Safety.1 Set the voltmeter to the 10 volts

Additional Procedures Battery Verification, LC 575 - 3 Battery Verification, LC 575 Before you begin, remove the following:• I/O door• Logic board•

Additional Procedures Battery Verification, LC 575 - 4 1 Set the voltmeter to the 10 volts DC scale.2 Hold the positive probe of the voltmeter to th

Additional Procedures Battery Replacement, LC 520 - 5 Battery Replacement, LC 520 Before you begin, remove the following:• I/O door• Logic board ± W

Additional Procedures Battery Replacement, LC 520 - 6 Caution: Review the ESD precautions in Bulletins/Safety.1 Insert a small flat-blade screwdri

Specifications I/O Devices - 7 I/O Devices Keyboard Standard 80-key Apple keyboard with numeric keypad; ADB connectorSoft power-on switch2.5 mm trav

Additional Procedures Battery Replacement, LC 520 - 7 3 Grasp the battery and remove it from the holder.4 Return the battery to Apple for proper dis

Additional Procedures Battery Replacement, LC 575 - 8 Battery Replacement, LC 575 Before you begin, remove the following:• I/O door• Logic board Cau

Additional Procedures Battery Replacement, LC 575 - 9 1 Pull up and disconnect the connector.2 Pull up and remove the battery from its hook-and-loop

Service Source K Adjustments Macintosh LC 520, 550, 575

Adjustments Geometry - 1 Geometry Before you begin, remove the rear cover. ± Warning: This product contains high voltage and a high-vacuum picture

Adjustments Geometry - 2 Note: The controls on this monitor require a small hex-head plastic tool to make adjustments. If the tool is long, it wil

Adjustments Geometry - 3 Vertical Center 1 Use Display Service Utility to display the All-White Screen test pattern.2 Using a hex-head plastic adjus

Adjustments Geometry - 4 Horizontal Center Using a hex-head plastic adjustment tool, adjust the horizontal center (HS) control until the raster is c

Adjustments Geometry - 5 Vertical Size 1 Using a hex-head plastic adjustment tool, adjust the vertical height (VH) control until the raster height i

Adjustments Geometry - 6 Horizontal Size Note: Due to video features and timing differences across the Apple line of Macintosh computers, the widt

Specifications Sound and Video - 8 Sound and Video Sound Generator Records at 11 kHz or 22 kHz sample ratePlays back at 22 kHz sample rateTwo speake

Adjustments Geometry - 7 Using a hex-head plastic adjustment tool, adjust the horizontal width (HW) control until the raster is 9 1/4 inches (± 1/8

Adjustments Geometry - 8 Focus 1 Use Display Service Utility to display the Focus test pattern.2 Using a hex-head plastic adjustment tool, adjust th

Adjustments Video - 9 Video Before you begin, remove the rear cover. ± Warning: This product contains high voltage and a high-vacuum picture tube.

Adjustments Video - 10 Replacement Note: Perform the cutoff adjustment whenever you replace the CRT or the analog board.

Adjustments Video - 11 Cutoff Note: Perform the cutoff and white balance adjustments after the monitor has been on for at least 10 minutes.1 Use D

Adjustments Video - 12 brightness control to midrange.4 Using a hex-head plastic adjustment tool, set the red (RB), green (GB), and blue (BB) backgr

Adjustments Video - 13 5 Set the green (GG) and blue (BG) drive controls to their 3/4 position by turning the controls to their full clockwise posit

Adjustments Video - 14 7 Using a hex-head plastic adjustment tool, adjust VG2 until the first bar in the test pattern is completely black and the se

Adjustments Video - 15 White Balance Note: Perform the cutoff and white balance adjustments after the monitor has been on for at least 10 minutes.

Adjustments Video - 16 3 Select the Screen Control Panel in the Control Panels folder. Drag the brightness control to midrange.

Specifications Electrical - 9 Electrical Line Voltage 100–240 VAC; Universal power supply Frequency 47–63 Hz, single phase Maximum Power 120 W

Adjustments Video - 17 4 Note the predominant color.5 Using a hex-head plastic adjustment tool, alternately adjust the red (RB), green (GB), and blu

Adjustments Video - 18 Note: The darkest bar must remain completely black throughout the rest of the procedure. If you notice a predominant color

Adjustments Video - 19 7 Check the four darkest bars, and if necessary, adjust the red (RB), green (GB), and blue (BB) background controls until the

Adjustments Video - 20 8 Use Display Service Utility to display the All-White Screen test pattern.9 Using the light meter, adjust the sub-contrast c

Adjustments Video - 21 Important: Over time, light meter tolerance can vary. If you doubt your meter’s accuracy, verify the readings with a known-

Adjustments Convergence - 22 Convergence Before you begin, remove the rear cover. ± Warning: This product contains high voltage and a high-vacuum

Adjustments Convergence - 23 1 Use Display Service Utility to display the Crosshatch I test pattern.2 Using a hex-head plastic adjustment tool, adju

Adjustments Convergence - 24 3 Using a hex-head plastic adjustment tool, adjust the N/S amp control for best convergence of horizontal lines at the

Adjustments Geometric Distortion - 25 Geometric Distortion Before you begin, remove the rear cover. ± Warning: This product contains high voltage

Adjustments Geometric Distortion - 26 1 Use Display Service Utility to display the Crosshatch I test pattern.2 Verify that the boxes on the top row

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

Adjustments Geometric Distortion - 27 ± Warning: The entire yoke assembly has very high voltage. To prevent electrical shock, do not touch the yok

Adjustments Geometric Distortion - 28 5 Using a hex-head plastic adjustment tool, adjust the control that is appropriate for the distortion.6 If the

Adjustments Geometric Distortion - 29 7 If the display is still distorted, repeat the vertical angle and pin phase adjustments.8 If you can’t correc

Adjustments Yoke - 30 Yoke Before you begin, remove the rear cover. ± Warning: This product contains high voltage and a high-vacuum picture tube.

Adjustments Yoke - 31 ± Warning: Because you must make yoke adjustments from the rear of the computer, use a mirror to view the computer screen. D

Adjustments Yoke - 32 1 Using an insulated Phillips screwdriver, loosen the yoke clamp screw two or three turns.2 Switch on the computer.Yoke ClampS

Adjustments Yoke - 33 3 With one hand, grasp the plastic yoke collar and rotate it until the top and bottom edges of the picture are parallel with t

Adjustments Yoke - 34 4 Switch off and unplug the computer.5 Discharge the CRT.6 Hold the plastic yoke collar in position and carefully tighten the

Adjustments Yoke - 35 8 Verify that the top and bottom edges of the picture are parallel with the top and bottom of the bezel.

Adjustments Light Meter Setup - 36 Light Meter Setup Note: This topic covers setup for two light meters: Models L-248 and 246. Model L-248 1 Press

Specifications Environmental - 11 Environmental Operating Temperature 50–104° F (10–40° C) Storage Temperature -40 to 149° F (-40 to 65° C) Relative

Adjustments Light Meter Setup - 37 2 Luminance tests will instruct you to move the side switch either to the low position (2-10) or the high positio

Adjustments Light Meter Setup - 38 Model 246 Note: Remove the metal slide, if installed, from the top of the light meter. Install the white lens w

Adjustments Light Meter Setup - 39 4 Read the red scale while you perform the Brightness and Contrast adjustments in the Video topic.

Service Source K Exploded View Macintosh LC 520, 550, 575

Exploded View 1 Exploded View Screw (4) Screw (4) Screw (4) Screw Screw (5)Hard Drive*Hard DriveCarrier922-0621Hard DriveConnectorAdapter922-1820Re

Service Source K 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. B

Service Source Basics Macintosh LC 520, 550, 575

Troubleshooting Symptom Charts/Video - 2 Symptom Charts Video Screen is black, too dark, or too bright; audio and drive operate1 Adjust contrast bu

Troubleshooting Symptom Charts/Video (Continued) - 3 Video (Continued) Single vertical or horizontal line is displayed1 Replace analog board. 2 R

Troubleshooting Symptom Charts/Video (Continued) - 4 Video (Continued) Out of convergence (color bleeds from text or lines)1 Perform convergence

Troubleshooting Symptom Charts/Video (Continued) - 5 Video (Continued) Out of focus 1 Perform focus adjustment. Refer to “Focus” in Adjustments c

Troubleshooting Symptom Charts/Video (Continued) - 6 Video (Continued) Linearity bad (size of text/graphics differs at top, bottom, or sides of s

Troubleshooting Symptom Charts/Video (Continued) - 7 Video (Continued) Raster distorted (barrel-shaped, corners not square, stretched or compress

Troubleshooting Symptom Charts/Floppy Drive - 8 Floppy Drive Audio and video are present, but internal floppy drive does not operate1 Replace bad di

Troubleshooting Symptom Charts/Floppy Drive (Continued) - 9 Floppy Drive (Continued) Does not eject disk 1 Insert opened paper clip into hole bes

Troubleshooting Symptom Charts/Floppy Drive (Continued) - 10 Floppy Drive (Continued) Unable to insert disk all the way1 To eject previously inse

Troubleshooting Symptom Charts/Hard Drive - 11 Hard Drive Internal or external hard drive does not operate1 Verify that SCSI loopback card is not at

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

Troubleshooting Symptom Charts/CD-ROM Drive - 12 CD-ROM Drive CD-ROM drive does not accept disc1 Replace disc (if dirty or damaged). 2 Remove front

Troubleshooting Symptom Charts/Peripheral - 13 Peripheral Cursor does not move 1 Check mouse connection.2 If mouse was connected to keyboard, connec

Troubleshooting Symptom Charts/Peripheral (Continued) - 14 Peripheral (Continued) Cannot double-click to open application, disk, or server1 Remov

Troubleshooting Symptom Charts/Peripheral (Continued) - 15 Peripheral (Continued) Known-good ImageWriter or ImageWriter II does not print1 Make s

Troubleshooting Symptom Charts/Miscellaneous - 16 Miscellaneous Clicking, chirping, or thumping sound1 Replace analog board.2 Replace logic board. R

Troubleshooting Symptom Charts/Miscellaneous (Continued) - 17 Miscellaneous (Continued) Screen shows “Sad Macintosh” icon and black vertical line

Troubleshooting Symptom Charts/Miscellaneous (Continued) - 18 Miscellaneous (Continued) “Sad Macintosh” icon 1 Replace bad disk with known-good d

Service Source K Take Apart Macintosh LC 520, 550, 575

Take Apart Rear Housing - 1 Rear Housing No preliminary steps are required before you begin this procedure. ± Warning: This product contains high

Take Apart Rear Housing - 2 Note: If the rear cover has bronze tape on the rear cover shield, remove the tape before removing the rear cover. Bend

Basics Product Information - 2 Product Information Identifying Features The LC 575 logic board includes a 68LC040 processor, an additional communica

Take Apart Rear Housing - 3 1 Using a Torx screwdriver, remove the five screws. 2 Lift off the rear cover.Rear Housing

Take Apart Fan - 4 Fan Before you begin, remove the rear cover. ± Warning: This product contains high voltage and a high-vacuum picture tube. To p

Take Apart Fan - 5 Push out the two latches and remove the fan assembly.LatchFanLatch

Take Apart Analog Board - 6 Analog Board Before you begin, • Remove the rear cover• Discharge the CRT• Remove the anode cap ± Warning: This produc

Take Apart Analog Board - 7 1 Disconnect the two ground cables from the degauss panels.Degauss PanelGround Cable Ground Cable

Take Apart Analog Board - 8 2 Disconnect the internal microphone connector.InternalWARNING: High Voltage AreasMicrophoneConnector

Take Apart Analog Board - 9 3 Disconnect the following cables from the analog board:• Degauss cable from BP2 (use a small screwdriver to release the

Take Apart Analog Board - 10 5 Caution: Twisting, bending, or applying force to the video board assembly could damage the neck of the CRT. Be sure

Take Apart Analog Board - 11 6 Remove the analog board. Replacement Note: Some analog boards may include a test jumper (located at BD 11). To avoi

Take Apart I/O Door - 12 I/O Door No preliminary steps are required before you begin this procedure. Caution: Review the ESD precautions in Bullet

Basics Product Information - 3 Compatibility Notes You can exchange the chassis harness assembly of the LC 520 or LC 550 with the newer chassis harn

Take Apart I/O Door - 13 1 Remove the two screws. 2 Push down on the two tabs and remove the I/O door.TabTabI/O Door

Take Apart Logic Board - 14 Logic Board Before you begin, remove the I/O door. Caution: You can access and remove the LC 520 logic board merely by

Take Apart Logic Board - 15 Pull out the logic board.Logic Board

Take Apart Drive Bezel - 16 Drive Bezel No preliminary steps are required before you begin this procedure. Caution: Review the ESD precautions in

Take Apart Drive Bezel - 17 Using a flat-blade screwdriver, push up the latch. Pull down and remove the drive bezel. LatchDriveBezel

Take Apart Floppy Drive - 18 Floppy Drive Before you begin, remove the drive bezel. Caution: You can access and remove the floppy drive merely by

Take Apart Floppy Drive - 19 Note: The LC 520 includes an auto-inject 1.4 MB floppy drive and a chassis harness assembly that requires a floppy dr

Take Apart Floppy Drive - 20 Push down the latch and pull out the floppy drive.FloppyDriveLatch

Take Apart Floppy Drive - 21 Macintosh LC 520 Auto-inject Floppy Drive 1 Pull out the floppy drive connector adapter Replacement Note: Be sure to

Take Apart Floppy Drive - 22 2 Remove the four mounting screws and remove the floppy drive from the carrier.Auto-injectFloppy DriveAuto-inject Flopp

Service Source K Specifications Macintosh LC 520, 550, 575

Take Apart Floppy Drive - 23 3 Pull out the sides of the floppy drive shield, lift the back of the shield, and remove it from the floppy drive.Auto-

Take Apart Floppy Drive - 24 Macintosh LC 550 and 575 Manual-inject Floppy Drive Remove the four mounting screws and remove the floppy drive from th

Take Apart CD-ROM Drive - 25 CD-ROM Drive Before you begin, remove the drive bezel. Caution: You can access and remove the CD-ROM drive merely by

Take Apart CD-ROM Drive - 26 1 Pull up the latch and pull out the CD-ROM drive. CD-ROMLatchDrive

Take Apart CD-ROM Drive - 27 2 Pull out the CD connector adapter and the CD audio adapter. Replacement Note: Be sure to reinstall the CD connector

Take Apart CD-ROM Drive - 28 Replacement Note: Be sure to reinstall the correct drive connector adapter and CD audio adapter. The adapters used fo

Take Apart CD-ROM Drive - 29 3 Remove the four mounting screws and remove the CD-ROM drive from the carrier. Replacement Note: Replace the carrier

Take Apart Hard Drive - 30 Hard Drive Before you begin, remove the I/O door. Caution: You can access and remove the LC 520 hard drive merely by re

Take Apart Hard Drive - 31 1 Push down the latch and remove the hard drive.Hard DriveLatch

Take Apart Hard Drive - 32 2 Pull out the hard drive connector adapter. Replacement Note: Be sure to reinstall the hard drive connector adapter on

Specifications Processor - 1 Processor LC 520 Motorola 68030 microprocessor25 MHzBuilt-in memory management unit (MMU) LC 550 Motorola 68030 micropr

Take Apart Hard Drive - 33 3 Remove the four screws.4 Remove the hard drive from the carrier. Replacement Note: Replace the carrier on the new har

Take Apart Chassis Harness Assembly - 34 Chassis Harness Assembly Before you begin, remove the following:• Drive bezel• I/O door• CD-ROM drive• Flop

Take Apart Chassis Harness Assembly - 35 ± Warning: This product contains high voltage and a high-vacuum picture tube. To prevent serious personal

Take Apart Chassis Harness Assembly - 36Chassis Harness Take Apart StrategyBackgroundAfter product introduction, Apple Service adjusted the service s

Take Apart Chassis Harness Assembly - 37• Chassis 922-1824 supports the auto-insert Apple SuperDrive and CD-ROM drives earlier than the 300i+. This c

Take Apart Chassis Harness Assembly - 38For more information, refer to Apple Service Guide, Macintosh Computers, Vol. 3 (1994), page 110.Service Part

Take Apart Chassis Harness Assembly - 39Service Parts Now Available for Chassis 661-1094661-0981 Shield Kit (EMI shielding)922-1825 PCBA Front Panel

Take Apart Chassis Harness Assembly - 40Chassis Harness Take Apart ProceduresFirst remove the chassis harness assembly.EMI Shields1 Remove the EMI sh

Take Apart Chassis Harness Assembly - 41Speaker AssemblyFirst remove the EMI shields.Caution: The speaker wire connections on the chassis cable brid

Take Apart Chassis Harness Assembly - 421 Disconnect the speaker wire spade connector from the back of the speaker.2 Remove the Phillips screws from

Specifications Memory - 2 Memory RAM 4 MB of dynamic RAM on boardExpandable to 36 MB (100 ns or faster SIMMs)72-pin DRAM SIMM connector ROM 1 MB of

Take Apart Chassis Harness Assembly - 433 Slide out the wire connector.Replacement Note: The analog board slides into the computer and completes the

Take Apart Chassis Harness Assembly - 44Front Panel Control Board First remove the EMI shields.1 Disconnect the front panel control cable.2 Remove th

Take Apart Chassis Harness Assembly - 45Logic Board Connector and Cable AssemblyFirst remove the EMI shields, speaker assembly, and front panel contr

Take Apart Chassis Harness Assembly - 461 Stand at the front of the chassis, looking down at the top of the chassis, and disconnect the following in

Take Apart Chassis Harness Assembly - 472 Route the analog board and the CD-ROM/hard drive cables through the large square hole behind the CD-ROM dri

Take Apart Chassis Harness Assembly - 48Overview of replacement procedures (Detailed steps follow the overview.) Connect the logic board connector to

Take Apart Chassis Harness Assembly - 492 Arrange the logic board connector and cable assembly as shown.3 Face the connector slot of the logic board

Take Apart Chassis Harness Assembly - 50Logic Board Connector and Cable Assembly1 Slide the side extension of the logic board connector down the fron

Take Apart Chassis Harness Assembly - 513 Route the floppy drive cable through its opening at the back of the floppy drive bay.4 Carefully route the

Take Apart Chassis Harness Assembly - 52facing the front of the chassis and the power cables facing toward the outside edge of the chassis. Slip the

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 1

Take Apart Chassis Harness Assembly - 5310 To replace the speakers, front control panel board, and EMI shields, reverse the take-apart procedures abo

Take Apart CRT - 54CRTBefore you begin, remove the following:• Drive bezel• I/O door• CD-ROM drive• Floppy drive• Hard drive• Logic board• Rear cover

Take Apart CRT - 55±Warning: This product contains high voltage and a high-vacuum picture tube. To prevent serious injury, review CRT safety in Bull

Take Apart CRT - 562 Lift off the CRT.Replacement Note: Be sure the microphone cable is not caught under the CRT.CRTMicrophone Cable

Take Apart Internal Microphone - 57Internal MicrophoneBefore you begin, remove the following:• Drive bezel• I/O door• CD-ROM drive• Floppy drive• Har

Take Apart Internal Microphone - 58±Warning: This product contains high voltage and a high-vacuum picture tube. To prevent serious injury, review CR

Take Apart Front Bezel - 59Front BezelTo remove the front bezel, remove the following:• Drive bezel• I/O door• CD-ROM drive• Floppy drive• Hard drive

Take Apart Front Bezel - 60±Warning: This product contains high voltage and a high-vacuum picture tube. To prevent serious injury, review CRT safety

Service Source K Upgrades Macintosh LC 520, 550, 575

Upgrades Macintosh Processor Upgrade - 1 Macintosh Processor Upgrade Before you begin, remove the following:• I/O door• Logic board• Card in PDS slo