Apple Desktop Bus Keyboard: Difference between revisions
Rewrite: power key resets the IIGS (Control-Command-Reset), it does not switch it on; FCC ID BCG5ARA9M0330 is the later Alps label only; cite IIGS Hardware Reference ch. 6 (key rollover, M50740); ADB facts cited to Family Hardware pages; remove uncited claims (ports in parallel, ADB fuse, four retention tabs, power key not a keycode); release_date param fixed |
Update links to Apple Extended Keyboard after page move |
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| Line 54: | Line 54: | ||
* [[Apple Desktop Bus Mouse]] | * [[Apple Desktop Bus Mouse]] | ||
* [[Apple Keyboard (M0116)]] | * [[Apple Keyboard (M0116)]] | ||
* [[Apple Keyboard|Apple Extended Keyboard]] | * [[Apple Extended Keyboard|Apple Extended Keyboard]] | ||
* [[Apple IIGS]] | * [[Apple IIGS]] | ||
* [[Retrobrite]] | * [[Retrobrite]] | ||
Latest revision as of 19:26, 1 October 2026
| Apple Desktop Bus Keyboard | |
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 |
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| Apple Desktop Bus Keyboard | |
| Manufacturer | Apple Computer, Inc. (made by Alps Electric and SMK) |
| Type | Computer keyboard |
| Release date | September 1986 (with the Apple IIGS) |
| Interface | Apple Desktop Bus |
| Compatible | Apple IIGS and ADB-equipped Macintosh computers |
| Successor | Apple Keyboard (M0116) |
| Model | A9M0330 (part number 658-4081 on early Alps units) |
The Apple Desktop Bus Keyboard was sold with the Apple IIGS, and so is often called the Apple IIGS Keyboard. The IIGS and its keyboard were the first Apple products with the Apple Desktop Bus, including a second port on the keyboard for daisy-chaining the Apple Desktop Bus Mouse, the first with a power key, and the first in the "Platinum" design. Deskthority gives the production years as 1986-1992.[1] On the IIGS the power key does not switch the computer on or off: pressed with Control and Command it resets the machine. The ADB microcontroller treats Control-Command-Reset as a special key code, halts the running program and restarts the computer.[1][2]
Apple's IIGS hardware reference describes the keyboard's behaviour: automatic key repeat with rate and delay set from the Control Panel, n-key rollover for the modifier keys, and two-key lockout for the alphanumeric keys, so a third key pressed at the same time as two others is not recognised.[2]
Variants
[edit | edit source]The keyboard was made by Alps in Japan and by SMK in Taiwan, with different switches.[1]
| Version | Rear label | Switches | Notes |
|---|---|---|---|
| Alps (Japan), earlier | part number 658-4081 | Alps SKCM Orange | Caps Lock is an Alps SKCL Lock; cream on one orange example |
| Alps (Japan), later | model A9M0330, FCC ID BCG5ARA9M0330 | Alps SKCM Salmon (apparently) | the later label matches the SMK version; the link to salmon switches is Deskthority's speculation |
| SMK (Taiwan) | model A9M0330, FCC ID BCG47FA9M0330 | white tactile SMK Alps-mount | PCB part number 2J-M9020-02B; double-shot keycaps, slightly darker than the Alps version |
Photographed controller date codes are 8844 on an SMK example and 9041 on a salmon Alps example. Deskthority suggests the change to salmon switches may coincide with orange Alps switches going out of production around 1991.[1] It also infers from the way the parts yellow that the case and space bar are ABS and the other keycaps a different plastic, possibly PBT.[1]
ADB
[edit | edit source]The keyboard is an encoded ADB device; keyboards default to ADB address $02.[3] On the IIGS, all input devices on the ADB are controlled by the ADB microcontroller, an M50740 with 96 bytes of RAM and 3K of ROM, and Apple II programs read the keyboard through the Keyboard Data register at $C000.[2] The ADB connector carries the data line on pin 1, pulled up to +5 V through a 470 Ω resistor on the computer's logic board; POWER.ON on pin 2 (on the Macintosh II family a key on the ADB keyboard grounds it to pin 4 to switch the power supply on; on other models it is not connected); +5 V on pin 3; and ground on pin 4.[4] All ADB devices together may draw no more than 500 mA, and Apple does not recommend daisy-chaining more than three devices on one port.[5] See Apple Desktop Bus for the protocol.
Maintenance and repair
[edit | edit source]Both switch types are long out of production, so replacement switches come from donor keyboards.
Keyboard dead
[edit | edit source]- Try the keyboard on another ADB machine and with a known-good ADB cable.
- At the computer's ADB port, measure +5 V between pin 3 and pin 4. Pin 1 should idle high through the 470 Ω pull-up.[4]
- Keep the chain short: no more than three devices on one port.[5]
Dead or intermittent key
[edit | edit source]- Remove the keycap, flush the switch with isopropyl alcohol while working it, and let it dry fully before testing.
- If that fails, desolder the switch and replace it from a donor of the same version.
Caps Lock will not latch
[edit | edit source]Caps Lock uses a latching switch (Alps SKCL Lock on the Alps boards), which a standard switch cannot replace.[1]
See also
[edit | edit source]- Apple Desktop Bus
- Apple Desktop Bus Mouse
- Apple Keyboard (M0116)
- Apple Extended Keyboard
- Apple IIGS
- Retrobrite
References
[edit | edit source]- ↑ 1.0 1.1 1.2 1.3 1.4 1.5 1.6 Deskthority wiki, "Apple Desktop Bus Keyboard": model A9M0330, part number 658-4081 (older Alps version), FCC IDs BCG47FA9M0330 (SMK) and BCG5ARA9M0330 (newer Alps), Alps SKCM Orange and Salmon and SMK Alps-mount switches, Alps SKCL Lock for Caps Lock, production 1986-1992, controller date codes, and photographs of each version. Community wiki, secondary source. Retrieved 2026-09-30.
- ↑ 2.0 2.1 2.2 Apple Computer, Apple IIGS Hardware Reference, 2nd edition (1989), chapter 6, "The Apple Desktop Bus", pp. 124-127. Hosted as File:Apple IIGS Hardware Reference 1989.pdf.
- ↑ Apple Computer, Guide to the Macintosh Family Hardware, 2nd edition (1990), chapter 8, Table 8-16, p. 318. Hosted as File:Apple Guide to the Macintosh Family Hardware 2nd Edition 1990.pdf.
- ↑ 4.0 4.1 Guide to the Macintosh Family Hardware, 2nd ed., Table 8-1, p. 288.
- ↑ 5.0 5.1 Guide to the Macintosh Family Hardware, 2nd ed., p. 292.