Macintosh LC 630 General Maintenance

This page covers routine care of the Macintosh LC 630, Quadra 630, Performa 630 series and LC 630 DOS Compatible, which Apple services as one family.

The machine in brief

Apple specification, 630 series

Item	Specification
Processor	LC 630: 68LC040 at 33 MHz. Quadra 630: 68040 with FPU at 33 MHz. LC 630 DOS Compatible: 68040 at 33 MHz plus an 80486DX2 at 66 MHz
DRAM	4 MB built in; 36 MB maximum on a one-slot board (661-0158), 52 MB on a two-slot board (661-1114). 72-pin, 80 ns or faster
ROM	1 MB
Video memory	A 1 MB DRAM frame buffer. Not expandable on any 630-series machine
Hard drive	IDE, 250 MB or 350 MB (500 MB on the DOS Compatible)
Sound	8-bit monophonic input; 8-bit stereo output, 16-bit in CD mode
Expansion	114-pin LC PDS; 112-pin communications slot; 60-pin video-in slot; 10-pin TV tuner connector
Line voltage	100–240 VAC, 50–60 Hz
Maximum power	45 W, monitor excluded
Height	4.3 in (10.95 cm)
Weight	17 lb (7.7 kg) without a CD-ROM drive; varies with options

Apple's part numbers for the rest of the machine: power supply 661-0170, front panel control board 661-0139, floppy drive 661-0121, CD-ROM drive 661-0913, hard drive 661-0070 (250 MB), 661-0068 (350 MB) or 661-0146 (500 MB), and the Macintosh Processor Upgrade card 661-0255.

Getting inside

Apple designed the 630 for quick service. Remove the rear plastic panel and the logic board slides straight out of the chassis; remove the front plastic panel to reach the drives. Plastic panels cover the metal bottom case, the top cover shield and the left, right and rear sides.

Disconnect the mains lead first. The power supply is a separate mains-fed module — there is no CRT or analogue board in this machine, so with the supply's own cover on there is nothing at mains potential once the lead is out.

Regular cleaning

• Blow the dust out of the logic board, the power supply, the fan and the case vents. The 630 has a fan

 on a bracket that also carries the video daughterboard; a clogged fan is worth catching.

• Clean the processor heat sink and the area around it.
• Clean the front-panel volume buttons and the headphone jack area. Apple lists jammed front-panel

 control buttons as the cause of a constantly flashing menu bar or constant beeping, so they are worth
 keeping free.

• If a DOS Compatibility Card is fitted, clean all three of its boards.
• Case plastics: a soft cloth with water or mild detergent. Avoid solvents, which craze this era of ABS.

 For yellowing, see Retrobrite.

PRAM battery

Apple's documentation for this machine names no battery part number, no voltage and no replacement threshold. The Service Source has no Battery Verification procedure, its exploded view lists no battery part, and its specifications give only "long-life lithium battery" for the clock and calendar. That is the honest position and nothing is invented here to fill it.

Two things are nevertheless settled:

• Apple part 742-0011 is the LC-series part and does not belong here. It is the 3.6 V lithium half-AA that appears in the exploded view of the LC Series / Quadra 605 manual, covering the Macintosh LC, LC II, LC III, LC 475 and Quadra 605, and it appears nowhere in the 630 documentation.
• "4.5 V" is a misreading, and so is "5.4 V". Apple's symptom charts for this machine contain the step "Unplug 4.5 battery, wait 20 seconds, plug in battery, and restart computer" in one entry and "Unplug 5.4 battery…" in another — the same instruction with two different numbers. Apple's Performa 630 Series Service Source prints "5.4" in the very entry where the LC 630 manual prints "4.5". Those are section cross-references in Apple's own numbering, not voltages — no battery is both 4.5 V and 5.4 V. The genuine 4.5 V pack in Apple's range belongs to the Performa 5000 series.

So: read the cell in your own machine. Its chemistry and voltage are printed on it, and that is the only figure worth working from on this chassis.

What Apple does give is a diagnostic: where the machine is completely dead — no fan, no LED — its chart has you check external power, try a known-good keyboard, reseat the logic board, then unplug the battery, wait twenty seconds, plug it back in and restart.

Take the battery out before the machine goes into storage. A leaking cell on a board of this age does damage that looks very like capacitor leakage and spreads under nearby chips. Identify the chemistry before choosing a neutraliser — bicarbonate of soda for a lithium cell, vinegar for an alkaline one; the wrong one makes the corrosion worse. For cleaning and trace repair see Battery Explosion, Capacitor or Corrosion Damage; for cell options see Battery Refurbishment.

Connector and socket care

The slide-out board design means the board gets handled, and the edge connectors and sockets take the wear. Worth checking and reseating:

• DRAM SIMM sockets — an eight-tone error chord at startup is Apple's documented symptom for a SIMM

 problem, and its first instruction is simply to reseat them.

• The processor socket.
• The LC PDS, communications slot and video-in slot.
• The monitor-out daughterboard connection on the fan bracket — Apple's second check for a dark

 screen when audio, drives and fan are all working.

• The 40-pin IDE connector and the internal power connector.

Reseat before you clean, and clean before you replace. Contact cleaner and a soft brush are enough for oxidised sockets.

Common failure points

Surface-mount capacitor leakage

The logic board carries nine surface-mount electrolytics: six 47 µF 16 V and three 100 µF 6.3 V. Leakage causes lost or distorted sound, intermittent starting and corroded traces. Full specifications, the location map and the procedure are on Macintosh LC 630 Capacitor Replacement Guide.

Macintosh LC 630 logic board 820-0548-B. The nine surface-mount electrolytics are marked with their values and positive terminals. Source: Recap-a-Mac.

Error chords

Apple's documented startup chords for this family:

Symptom	Apple's sequence
Eight-tone error chord at startup	Reseat the SIMMs; replace the SIMMs; replace the logic board, keeping the customer's SIMMs
Four-tone error chord at startup	Disconnect the hard drive power cable and reboot; if that is clean, test and replace the hard drive. Then disconnect the floppy cable and reboot; if that is clean, replace the floppy drive. Then replace the logic board

See also Sad Mac Error Codes.

Video

The DB-15 monitor port is on a built-in video daughterboard, not on the logic board, and the daughterboard is carried on the fan bracket. That changes the diagnosis of a dark screen:

• Screen dark, audio and at least one drive working, fan running, LED lit: check the video

 connections, then the monitor-out daughterboard connection on the fan bracket, then reseat the logic
 board, then adjust or replace the monitor.

• Part or all of the screen bright but no picture, audio present: reseat the logic board, then

 replace the fan/video card bracket, then the monitor.

Video memory is a 1 MB DRAM frame buffer shared with the system. No 630-series machine supports video memory expansion — that is a design limit, not a fault.

IDE hard drive

The 630 was Apple's first desktop Macintosh with an IDE drive, and Apple flags the interface as new in its own manual. Its guidance is short: the internal IDE drive behaves like a SCSI drive from the system's point of view, IDE drives must be replaced like for like, and the IDE drive does not affect SCSI ID selection or termination. Seven external SCSI devices can still be daisy-chained from the external port.

For a flashing question mark at startup on a machine with empty PDS and communications slots, Apple's sequence is: diagnose the drive with Disk First Aid; repair and update the driver with Drive Setup 1.0.3; if repair is impossible, back up, reformat with Drive Setup 1.0.3, update the driver and do a clean install. Apple also requires System 7.1.2 or later on this family.

TV tuner and video-in cards

Apple documents one specific hardware revision fault: if some UHF channels cannot be tuned, the Rev. A video-in card 661-0159 should be replaced with the Rev. B card 661-1073. On machines with an MPEG card, video that will not play or a hang when playing is diagnosed by the chip at location U12: if it is marked 341S0205 the connections are at fault, and if it is not, the MPEG card is replaced.

Things that are not faults

• No power switch. The 630 powers on exclusively through the soft power key on the keyboard. A

 machine that will not start with a suspect keyboard is a keyboard problem.

• Crackling on sounds other than system beeps. Apple's fix is software: Audio Volume Extension 1.1

 or later.

• Rattling at startup. On machines with the Apple External Video Connector fitted, Apple's remedy

 is to fold the cable away so that it stops touching the fan blades.

• Video memory cannot be increased. See above.

DOS Compatibility Card

The DOS-compatible machines carry three extra boards — the DOS-compatible board, a sound daughterboard and an adapter board in the PDS — plus a DRAM SIMM on the main logic board. The DOS board takes its own 72-pin, 80 ns or faster SIMMs, to 32 MB.

Reseating after transport is the first thing to try when a DOS card stops being recognised: disconnect the 26-pin adapter board cable, lift the battery end of the adapter board from the PDS, and refit both squarely. Apple identifies a sound fault specific to DOS-compatible machines with replacement part 661-0253.

Storage

• Remove the battery.
• Store cool and dry, and not in a sealed plastic bag with the machine still warm.
• Take out third-party expansion cards, and note the configuration somewhere you will find it again.
• Back up the IDE drive before it becomes the only copy.

Related pages

• Macintosh LC 630
• Macintosh LC 630 Capacitor Replacement Guide
• Macintosh LC 630 Troubleshooting
• Macintosh LC 630 DOS Compatible
• Macintosh Quadra 630
• Macintosh Performa 630
• LC 630/Quadra 630/ Performa 640 Service Source
• Hard Drive Maintenance and Repair
• Recommended Tools