Apple Tape Backup 40SC
| Apple Tape Backup 40SC | |
|---|---|
 |
|
| Apple Tape Backup 40SC (Stephen Edmonds, CC BY-SA 2.5) | |
| Manufacturer | Apple Computer, Inc. |
| Type | External SCSI quarter-inch mini-cartridge tape drive |
| Release date | 1987 |
| Discontinued | 1994 |
| Price | US$1,499 |
| Interface | SCSI, two 50-conductor ports |
| Compatible | Macintosh Plus, Macintosh SE, Macintosh II |
| Dimensions | 78 × 246 × 266 mm (H × W × D) |
| Weight | 3.3 kg (7.3 lb) |
| Model | M2640 |
| Power | 85-270 V AC, 47-64 Hz, 15 W |
| Storage | 38.5 MB formatted per cartridge |
| Media | DC2000 quarter-inch mini-cartridge (Apple 40MB Tape Cartridge) |
The Apple Tape Backup 40SC is Apple's external SCSI tape drive for backing up Macintosh hard disks, using quarter-inch DC2000 mini-cartridges that hold 38.5 MB each. Apple's data sheet is dated July 1987, and the drive was sold until 1994.[1][2] Its case matches Apple's external CD-ROM and hard disk drives of the period, such as the AppleCD SC.[3] InfoWorld gave its price as $1,499 in December 1988, and reported in September 1989 that Apple would bundle Dantz Retrospect with it.[2]
Specifications
[edit | edit source]| Item | Value |
|---|---|
| Media | 0.25-inch magnetic tape mini-cartridge, 205 ft (62.5 m) |
| Formatted capacity | 38.5 MB |
| Recording | Group Code Recording; 12,500 ftpi flux density, 10,000 bpi; 24 serpentine tracks |
| Block size | 8,192 bytes (8,320 with 128 bytes of system data) |
| Tape speed | 60 in/s read/write; 90 in/s search and rewind |
| Drive data rate | 600 Kb/s raw; 400 Kb/s fully corrected |
| SCSI transfer rate | 21.3 Kb/s average with continuous tape motion; 500 Kb/s maximum burst |
| Rewind time | 27 s end to end |
| Power | 85-270 V AC, 47-64 Hz; 15 W |
| Operating environment | 5-45 °C (cartridge limited); 20-80% RH non-condensing |
| Size and weight | 78 × 246 × 266 mm; 3.3 kg |
Apple's July 1987 data sheet quotes the transfer rate as 1.25 megabytes per minute in burst mode and up to 1 megabyte per minute for volume backups, about 17 to 18 minutes for every 20 MB backed up, and gives an operating range of 10-35 °C.[1] The owner's guide's own maintenance chapter gives 50-95 °F and 20-80% relative humidity.[4]
Using the drive
[edit | edit source]The drive came with the Apple Tape Backup 40SC application disk, a formatted 40 MB tape cartridge, the owner's guide and a power cord.[4] The application backs up a whole HFS volume or partition, or individual files, and restores either; a volume backup can only be restored to a disk of exactly the same capacity. The application needs System file 4.2 or later and Finder 6.0 or later to run from a hard disk.[4] The data sheet lists the Macintosh Plus, SE and II with an Apple Hard Disk 20SC, 40SC or 80SC, or the internal equivalents.[1]
The factory SCSI ID is 1. The ID switch on the back panel is set with the point of a pin or straightened paper clip with the drive switched off; each push advances the number, and it cycles round if you overshoot.[4]
The cartridges have a record-lock switch at the upper left: to the left the drive can write, to the right the cartridge is write-protected.[4]
Hardware
[edit | edit source]Apple serviced the drive as modules: case top, power supply, tape backup mechanism on its baseplate, fan frame, fan, SCSI device-to-case cable and SCSI select switch.[5] Inside the cartridge slot are the tape head, the drive puck that turns the cartridge's own capstan, and two green buttons; holding the lower button in runs the drive motor, which Apple's cleaning procedure uses.[4]
Known faults
[edit | edit source]The rubber drive puck is the drive's weak point today. Steve (Mac84) on TinkerDifferent reported in 2025 that the capstan in every 40SC he found had become sticky and soft with age and would spread residue onto tapes if used. He measured an intact one at about 17.4 mm across, including a metal spindle of about 12.8-13 mm, and got a drive reading tapes again with a 3D-printed TPU replacement 17.8 mm across. He also found the drive band inside old cartridges dried out and brittle, and broke one tape by running it.[3] The Apple Tape Backup 40SC General Maintenance and Apple Tape Backup 40SC Troubleshooting Guide pages cover cleaning, the puck and Apple's symptom chart.
Documentation
[edit | edit source]- Apple Tape Backup 40SC Service Source: Apple's module-level service manual.
- Apple Tape Backup 40SC Documentation: the 1987 data sheet and the 1988 owner's guide.
Related pages
[edit | edit source]- Apple Tape Backup 40SC General Maintenance
- Apple Tape Backup 40SC Troubleshooting Guide
- AppleCD SC
- Hard Drive Maintenance and Repair
References
[edit | edit source]- ↑ 1.0 1.1 1.2 Apple Computer, Apple Tape Backup 40SC data sheet, M2235, July 1987, hosted as File:Apple Tape Backup 40SC Data Sheet (1987).pdf. Features; technical specifications (DC2000 cartridge, 38.5 MB, 8,192-byte blocks, 24 serpentine tracks, 60/90 in/s, 1.25 MB per minute burst and up to 1 MB per minute in volume mode, 17-18 minutes per 20 MB, 85-270 V, 15 W, 10-35 °C); system requirements; order numbers M2640 (drive) and M0132 (five-pack of 40MB tape cartridges).
- ↑ 2.0 2.1 "Apple Tape Backup 40SC", Wikipedia, en.wikipedia.org/wiki/Apple_Tape_Backup_40SC (retrieved 4 October 2026). Introduced 1987, discontinued 1994; price US$1,499 (citing InfoWorld, 5 December 1988, p. 88); Retrospect bundled from 1989 (citing InfoWorld, 25 September 1989, p. 33).
- ↑ 3.0 3.1 Mac84 (Steve), "Repairing my Apple Tape Backup 40SC Drive and Rescuing Apple History from 36 year old data tapes!", TinkerDifferent forum, 8 July 2025, tinkerdifferent.com. Soft, sticky capstans; measurements of an intact capstan; TPU replacements 17.4, 17.8 and 18 mm; spring-loaded hinged capstan platform; brittle cartridge tension bands; Apple software for System 6; Retrospect 4 under Mac OS 8.6 working with the drive.
- ↑ 4.0 4.1 4.2 4.3 4.4 4.5 4.6 Apple Computer, Apple Tape Backup 40SC Owner's Guide, 030-5631-A, 1988, hosted as File:Apple Tape Backup 40SC Owner's Guide (1988).pdf. Equipment p. 2 (PDF p. 16); SCSI ID p. 14 (PDF p. 28); general rules p. 36 (PDF p. 50); Chapter 5, Troubleshooting and Maintenance, pp. 86-95 (PDF pp. 100-109); Appendix A, Specifications, pp. 97-98 (PDF pp. 111-112).
- ↑ Apple Computer, Apple Tape Backup 40SC Service Source, hosted as File:Apple tape backup 40sc.pdf (see Apple Tape Backup 40SC Service Source). Troubleshooting: General p. 2, Symptom Charts/Miscellaneous pp. 3-7; Take Apart: Case Top pp. 2-4, Power Supply pp. 5-8, Tape Backup Mechanism pp. 9-11, Fan Frame pp. 12-13, Fan pp. 14-17, SCSI Device-to-Case Cable pp. 18-19, SCSI Select Switch pp. 20-21.