Macintosh LC 630 General Maintenance

Macintosh LC 630 logic board 820-0548-B (Recap-a-Mac)

Routine care for the Macintosh LC 630, Macintosh 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
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	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 mono 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
Power	100-240 V AC, 50-60 Hz; 45 W maximum, not including the monitor
Battery	4.5 V alkaline (Apple specification sheet)
Weight	17 lb (7.7 kg) without a CD-ROM drive; varies with options

Apple's service part numbers: 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), fan/video bracket 922-1160 and Macintosh Processor Upgrade card 661-0255.

Getting inside

Plastic panels cover the metal bottom case, the metal top shield and the sides. Remove the rear panel (the I/O door) and the logic board slides out of the back; remove the front panel (the drive bezel) to reach the drives. Apple's developer note gives the user's method: take out the two screws above the I/O connectors, press down the two tabs and pull the cover off, then pull the board straight out by its wire loop. The board plugs into a connector at the front of the case. Disconnect the mains lead first. The power supply is a separate mains-fed module; see Power supply before opening it.

Regular cleaning

• Apple's cleaning advice for the case: switch off, unplug, and wipe with a soft, lint-free cloth dampened with water. Do not use aerosol sprays, solvents or abrasives, and keep moisture out of the openings.
• Mouse: remove the ring and ball, clean the three rollers with a swab moistened with water, and wash the ball in warm soapy water if needed, drying it thoroughly.
• Inside, remove dust from the logic board, the power supply and the fan. The fan is on the bracket that also carries the video daughterboard.
• Keep the front-panel volume buttons free. Apple gives jammed front-panel buttons as the cause of a menu bar that flashes constantly or a machine that beeps constantly.
• For yellowed plastics, see Retrobrite.

Power supply

The supply is Apple part 661-0170. Apple publishes no rail voltages, tolerances or adjustment for it, and its power-related symptom chart entries end in replacing the supply. The machine is switched on through soft power from the keyboard's Power key (or the remote control); Apple's chart says the computer "powers on exclusively through softpower on keyboard", so a machine that will not start should be tried with a known-good keyboard.

The supply can be opened and recapped. With its cover off and the lead connected, the primary side is at mains potential, and the reservoir capacitor holds charge after the plug is pulled. Unplug it, discharge the reservoir and check with a meter before working on it.

PRAM battery

Apple's specification sheets give the battery as 4.5 V alkaline. The Service Source names no battery part number and gives no test voltage. Where the machine is completely dead (no fan, no LED), Apple's chart has you check the external power, try a known-good keyboard, reseat the logic board, then unplug the battery, wait 20 seconds, plug it back in and restart.

Take the battery out before the machine goes into storage. Alkaline leakage is neutralised with a weak acid such as vinegar, then rinsed and dried. A leaking cell damages traces and nearby chips in the same way as capacitor electrolyte. See Battery Explosion, Capacitor or Corrosion Damage and Battery Refurbishment.

Connector and socket care

The slide-out logic board plugs into a connector at the front of the case, so the board's edge contacts and sockets take wear. Check and reseat:

• the DRAM SIMM sockets: an eight-tone error chord at startup is Apple's symptom for a SIMM problem, and its first instruction is 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 working;
• the 40-pin IDE connector, the floppy connector and the internal power connector.

Reseat before cleaning, and clean before replacing.

Common failure points

Capacitor leakage

The logic board carries nine surface-mount electrolytics: six 47 µF 16 V and three 100 µF 6.3 V. The location map and procedure are on Macintosh LC 630 Capacitor Replacement Guide.

Error chords

Apple's error chords for the 630 series

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 startup is normal, test and replace the hard drive. Then disconnect the floppy cable and reboot; if startup is normal, replace the floppy drive. Then replace the logic board

See also Sad Mac Error Codes.

Video

The DB-15 monitor port is on a video daughterboard carried by the fan bracket.

• Screen dark with audio, at least one drive, fan and LED all working: 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, audio present but no picture: reseat the logic board, then replace the fan/video card bracket, then the monitor.

IDE hard drive

Apple notes that the IDE interface was new to Apple products. The internal IDE drive behaves like a SCSI drive to the system, must be replaced like for like, and has no effect on SCSI ID selection or termination. Apple's specification allows six external SCSI devices; the general information page of the same manual says seven.

For a flashing question mark at startup with empty PDS and communications slots, Apple's sequence is to check the drive with Disk First Aid, repair it, and update the driver with Drive Setup 1.0.3; if the drive cannot be repaired, back it up, reformat it with Drive Setup 1.0.3, update the driver and do a clean install. Several charts also require System 7.1.2 or later.

TV tuner, video-in and MPEG cards

If some UHF channels cannot be tuned, Apple replaces the Rev. A video-in card 661-0159 with the Rev. B card 661-1073. If video will not play with an MPEG card fitted, Apple checks the chip at U12: if it is marked 341S0205, check the connections; if not, replace the MPEG card.

Things that are not faults

• A machine that will not start with a faulty keyboard: it powers on through soft power from the keyboard, so test with a known-good keyboard first.
• Crackling on sounds other than system beeps is cured with Audio Volume Extension 1.1 or later.
• A rattle at startup on machines with the Apple External Video Connector is the cable touching the fan blades; fold it clear.
• Video memory cannot be increased on any 630.

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 SIMM, up to 32 MB. To reseat the adapter board, disconnect the 26-pin adapter board cable and lift the battery end of the board first. See Macintosh LC 630 DOS Compatible Troubleshooting.

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