AppleCD 150 General Maintenance

An AppleCD 300 with the top case removed; the AppleCD 150 is laid out the same way (Chris Whytehead, CC BY-SA 3.0)

Care, take-apart and the mains fuse for the AppleCD 150 and the AppleCD 300, which share one Service Source and the same case layout. Apple serviced both drives by exchanging modules: CD-ROM drive mechanism, power supply, rear panel parts, front panels and case.^[1]

Handling

Apple's guidelines for both drives:^[1]

Switch the drive off and make sure no SCSI devices are attached to it before working on it.
Work on a soft, grounded surface, and observe ESD precautions.
Never transport the drive with a disc or caddy inside, and use the original packing.
Never fit an AppleCD 300 drive mechanism in an AppleCD 150 case: the SCSI-device-to-case cable will not connect correctly.

The drive contains a mains power supply. Unplug the mains lead before removing the top case.

Taking the drive apart

Apple's procedures, in the order the Service Source gives them:^[1]

Top case: remove the six case screws and lift the top case off.
CD-ROM drive: remove the four drive mounting screws from the bottom of the case. Hold the drive and turn the case over, lift the back of the drive and disconnect the audio-out cable, the SCSI select switch cable, the SCSI-device-to-case cable and the power cable, then lift the drive out.
Power supply (top case and drive removed): remove the two power supply mounting screws from the bottom of the case, turn the case over holding the supply, untape the cables from the top of the supply and remove the ground wire screw. Lift the end of the supply furthest from the power cable, release the locking tab, disconnect the power cable and lift the supply out.
SCSI-device-to-case cable: with the drive lifted and the cable disconnected, remove the four cable mounting screws and pull the cable through the rear panel.
Rear panel: with the drive's cables disconnected, remove the ground wire screw and the two rear panel mounting screws, and lift the panel out.
Power switch/plug assembly (rear panel off): with a small flat-blade screwdriver, depress the bottom latch on the power plug and push it through the opening as far as it goes, then the top latch to push it out; repeat for the power switch. Pass the switch wires across the small channel to the plug opening and remove the assembly through it.
Audio-out assembly: one mounting screw holds it to the rear panel.
SCSI select switch (rear panel and audio-out assembly off): depress each of the two switch latches in turn with a small flat-blade screwdriver and work the switch out of the panel with a rocking motion.
Front panels: with the four drive screws out, turn the case over, lift the front of the drive and pull each front panel straight up and out.

Reassembly notes

Apple's replacement notes:^[1]

Refit the power cable connector to the drive ridged edge up, and route the power cable beneath the SCSI-device-to-case cable.
Refit the ground wire screw before reconnecting the power cable to the power supply.
Plug the SCSI select switch cable onto the left four pairs of pins in the drive's connector, with the looped wire on the connector facing the audio-out cable.
When fitting a new drive mechanism, first remove the jumpers over the left three pairs of pins in its SCSI select switch connector. The connector also carries the ID select and parity pins.

Mains fuse

The fuse is behind the rear panel. Remove the top case and the rear panel, then prise the fuse out of its holder with a small flat-blade screwdriver. Apple does not stock it as a service part: fit a type MT4, 250 V, 2 A fuse.^[1]

Discs and caddies

The 150 and 300 take discs in a CD caddy. A dirty or damaged disc is Apple's first cure for a drive that will not accept a disc.^[1] Apple's user's guide for the internal AppleCD 300i warns that dust on the lens can stop the drive reading discs, and that the computer should never be moved with a disc or caddy in the drive.^[2]

Capacitors

The Sony caddy mechanisms in these drives suffer from leaking surface-mount electrolytic capacitors, which shows up as a drive that keeps ejecting the caddy. The AppleCD 150 Capacitor Replacement Guide lists the nine capacitors on the Sony CDU-541-25. Apple published no component values for the power supply or the drive.^[3]^[1]

Related pages

References

↑ ^1.0 ^1.1 ^1.2 ^1.3 ^1.4 ^1.5 ^1.6 Apple Computer, AppleCD 150/300 Service Source, hosted as File:Applecd 150-300.pdf (see AppleCD 150/300 Service Source). Take Apart pp. 1-32: guidelines pp. 1-2, Top Case p. 3, CD-ROM Drive pp. 4-8, Power Supply pp. 9-12, SCSI-Device-to-Case Cable pp. 13-15, Rear Panel pp. 16-20, Power Switch/Plug Assembly pp. 21-23, Audio-Out Assembly pp. 24-25, SCSI Select Switch pp. 26-28, Front Panels pp. 29-31, Bottom Case p. 32; Exploded View; Additional Procedures, Fuse pp. 1-2.
↑ Apple Computer, AppleCD 300i User's Guide (1992), care and safety instructions (PDF p. 9), archive.org item AppleCD_300i_Users_Guide_1992; hosted as File:AppleCD 300i User's Guide (1992).pdf.
↑ llamamusic.com, "AppleCD 150 Caddy Eject Problem: PCB Capacitor Replacements", llamamusic.com/s50s550/AppleCD_150_Repair.html (retrieved 4 October 2026).

[ss-1] 1.0 ^1.1 ^1.2 ^1.3 ^1.4 ^1.5 ^1.6 Apple Computer, AppleCD 150/300 Service Source, hosted as File:Applecd 150-300.pdf (see AppleCD 150/300 Service Source). Take Apart pp. 1-32: guidelines pp. 1-2, Top Case p. 3, CD-ROM Drive pp. 4-8, Power Supply pp. 9-12, SCSI-Device-to-Case Cable pp. 13-15, Rear Panel pp. 16-20, Power Switch/Plug Assembly pp. 21-23, Audio-Out Assembly pp. 24-25, SCSI Select Switch pp. 26-28, Front Panels pp. 29-31, Bottom Case p. 32; Exploded View; Additional Procedures, Fuse pp. 1-2.

[ug300i-2] Apple Computer, AppleCD 300i User's Guide (1992), care and safety instructions (PDF p. 9), archive.org item AppleCD_300i_Users_Guide_1992; hosted as File:AppleCD 300i User's Guide (1992).pdf.

[llama150-3] usic.com, "AppleCD 150 Caddy Eject Problem: PCB Capacitor Replacements", llamamusic.com/s50s550/AppleCD_150_Repair.html (retrieved 4 October 2026).

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