Apple Tape Backup 40SC General Maintenance

Tape drive head, puck and green buttons, from Apple's owner's guide (figure 5-1)

Care of the Apple Tape Backup 40SC, its cartridges and its mechanism, from Apple's owner's guide and Service Source and a 2025 restoration. Apple asked owners to clean the head and the drive puck regularly; today the puck itself is usually the part that needs attention.

Safety

Apple's owner's guide warns that the drive "contains high-voltage components that retain an electrical charge, even after the unit is switched off". The power supply is a separate module that lifts out of the case. Unplug the mains lead before taking the case top off. Isopropyl alcohol is flammable, and Apple recommends safety glasses for the puck cleaning below, because the turning puck can throw alcohol out of the slot.

Handling and environment

Apple describes the drive as a mechanical device to be treated like a stereo tape deck: dropping, jarring or bumping it, especially while it is running, can cause a malfunction or damage the data on the cartridge. Keep it away from spilled liquids and from chemical or solvent fumes, including steam from a coffee maker. The owner's guide gives an operating range of 50-95 °F and 20-80% relative humidity.

Clean the outside with a soft, damp cloth, adding a drop of liquid detergent for stains.

Cleaning the head and puck

Apple's schedule was once a week for several backups a day and once a month for one backup a day, more often in a dusty or busy area. Apple named the 3M DC2000 Data Cartridge Drive Cleaning Kit (part number DC 051111-12628) as one option, and gave this procedure as the other. You need long-handled cotton swabs, 99% isopropyl alcohol and a non-conductive, non-metallic tool.

1. Make sure the drive is plugged in and switched on.
2. Soak a swab tip in alcohol.
3. Put the non-conductive tool into the left side of the drive and press the lower green button for about 20 seconds. The motor runs and the red activity light comes on.
4. Hold the swab tip firmly against the left side of the turning puck and move it up and down for about 20 seconds. The motor stops by itself about 20 seconds after the button is pressed.
5. Release the button and remove the swab.
6. Soak a fresh swab; do not reuse the one from the puck.
7. Rub it gently but firmly up and down the tape head, the shiny surface at the right rear of the drive, for 5 to 10 seconds, covering the whole head surface.
8. Wait 5 minutes for the head to dry before inserting a cartridge.

Never clean the head with a cleaner that contains active or abrasive ingredients.

The puck today

The puck (capstan) has turned soft and sticky on 40SC drives found in recent years, and running a tape on it spreads residue into the cartridge. A 2025 restoration on TinkerDifferent measured an intact puck at about 17.4 mm across, including a metal spindle of about 12.8-13 mm, and restored a drive with a 3D-printed TPU puck 17.8 mm across. The capstan sits on a spring-loaded, hinged platform, so the contact pressure against the cartridge is hard to judge, and the printed puck crept along its spindle after several uses and had to be pushed back. Inspect the puck before running any tape you care about. Apple's cleaning procedure above reaches it through the slot; replacing it needs the case open.

Cartridges

Apple's rules for the cartridges:

• Eject the cartridge after each backup or restore, and do not leave it in the drive for more than a day.
• Switch the drive on before inserting a cartridge.
• Let a cartridge acclimatise for 8 hours, or for as long as it has been in different conditions if that is less.
• Check the record-lock switch is to the left (unlocked) before formatting, clearing, backing up or verifying.

The drive band inside a DC2000 cartridge moves the tape. In the 2025 restoration, the bands in the old Apple cartridges were dried out and brittle and one snapped in use, while the bands from new old stock cartridges of the late 1990s were still springy. Treat any original cartridge as fragile.

Opening the drive

From the Service Source:

1. Case top: with a jeweller's screwdriver, press gently on the two holding tabs while pushing the case top up slightly. Then put the screwdriver straight into each of the two tab holes, one on each side, and nudge the top upwards as each tab releases. Do not prise; it can damage the case.
2. Power supply: press down on the back of the supply, push back its tab and lift it. Disconnect the power supply connector from the tape mechanism, the fan cable and the LED cable, then lift the supply free.
3. Tape mechanism: push back the holding tab with a flat-blade screwdriver and lift the mechanism and its baseplate onto the edge of the case. Open the end tabs on the SCSI device-to-case cable connector and disconnect it, then disconnect the power supply cable, the SCSI select switch cable and the LED cable, and lift the mechanism out.
4. Fan frame: with the mechanism resting on the edge of the case, push back the plastic tab and lift out the metal fan frame with the fan, SCSI device-to-case cable, fan cable and SCSI select switch attached.
5. Fan: two screws hold it to the frame; remove the two screws holding the upper SCSI connector, push the connector back through the frame to free the fan cable, and lift the fan out.
6. SCSI device-to-case cable: four screws. SCSI select switch: press in the four plastic arms on the back and push it through the fan frame.

Apple's note for exchange is to return the tape mechanism on its metal frame with the LED cable and SCSI select switch cable.

Capacitors

Apple published no component list for the power supply or the mechanism. Inspect both boards for leaking electrolytics when the case is open; Capacitor Failure Symptoms describes the signs.

Related pages

• Apple Tape Backup 40SC
• Apple Tape Backup 40SC Troubleshooting Guide
• Recommended Tools