Apple Design Keyboard

AppleDesign Keyboard
AppleDesign Keyboard M2980 (ISO layout)
Manufacturer	Apple Computer, Inc. (made by NMB and Alps Electric)
Type	Computer keyboard
Release date	1994
Interface	Apple Desktop Bus
Compatible	ADB-equipped Macintosh computers
Predecessor	Apple Extended Keyboard II
Successor	Apple USB Keyboard
Model	M2980

The AppleDesign Keyboard (model M2980) was Apple's first low-cost full-size Macintosh keyboard, full-size meaning it has a function-key row and a navigation cluster. It was introduced in 1994, uses rubber domes where the Apple Extended Keyboard II it replaced used Alps mechanical switches, and was followed by the Apple USB Keyboard. The FCC ID is BCGM-2980.

Most were made in "platinum" beige; a black version was shipped with the black Macintosh models. Apple's specification gives a 6 ft (1.8 m) cable permanently attached at the front of the keyboard and one ADB connector on the underside for a mouse or other pointing device; the Extended Keyboard II instead has an ADB port on each side. The US versions of the two keyboards have the same key layout. Some production runs are reported to have had detachable cables and Alps-compatible sliders.

Specifications

AppleDesign Keyboard specifications (Apple)

Item	Value
Keys	105: 60-key alphanumeric block, 18-key numeric keypad, four inverted-T cursor keys, 15 programmable function keys, six editing keys, Escape, Power-on/Reset
Indicators	three LEDs; Caps Lock works under the Mac OS, Num Lock and Scroll Lock only in some applications and other operating systems
Keyswitches	peak tactile force above 0.75 N; minimum life 10 million cycles; key travel printed as "approx. 4.5 cm"
Size	47.5 cm W × 17.5 cm D × 4.1 cm H (maximum)
Weight	1.2 kg (2.7 lb)
Keyboard angle	6-12°
Connector and cable	ADB 4-pin mini-circular; 6 ft (1.8 m) cable, attached
Power	150 mA typical with the LEDs on
Environment	operating 10-40 °C; storage −40 to 60 °C; 95% humidity maximum, non-condensing

Apple's figure for key travel, "approx. 4.5 cm", is evidently a misprint; 4.5 cm would exceed the keyboard's height.

Variants

There are at least four internal designs. They look alike from outside, but the keycap mount differs between them, so keycaps are not interchangeable, and the number of screw holes in the case differs.

Identifying the variant

Variant	Case screws	Domes and switches	Keycaps	Other markers
NMB dome with slider, "Version A"	4	white NMB sliders over bright yellow domes		Option keys 1 u; black barrel plate; long, wide rubber feet; controller marked "NMB16R2677"
NMB dome with slider, "Version B"	8	white NMB sliders over bright yellow domes	shorter, each with a post	Option keys 1.25 u; stepped Caps Lock (1.5:0.25); beige barrel plate; homing keys (D, K, numpad 5) have stems rotated 90°; long, narrow feet
Alps dome with slider	3	Alps "Type 2" dome with slider	OEM profile; Mexico: pad-printed ABS; Czech Republic: dye-sublimated PBT	thin metal plate held to the membrane assembly by melted plastic rivets; bottom row 1.5/1.25/1.5/6.5/1.5/1.25/1.5 u; Caps Lock slider offset to line up with Tab
Alps membrane dome		clear loose domes in a self-contained membrane module; dome housings identical to the Alps KFRF-1	integrated mount	curved black key mounting plate; controller marked "©APPLE, Inc"; 39 screws on the back of the membrane module

Three screw holes on the bottom of the case identify the Alps dome-with-slider board.

Construction

NMB variants

The upper shell carries white NMB sliders over bright yellow domes. The keyboard controller is marked "NMB16R2677", which is part of the reason the keyboard is attributed to NMB. The fixed cable exits through a cable channel. On Version B the stems of D, K and numpad 5 are rotated 90°, so note their orientation before removing them.

Alps dome with slider

The metal plate is fixed to the membrane assembly by melted plastic rivets, not screws, so the plate cannot be separated without cutting them. The stabiliser wires are hinged on the keys and slide in recesses in the membrane assembly.

Alps membrane dome

The self-contained membrane module screws to the base of the keyboard. It has three membrane layers, the upper one printed with Alps branding, and loose clear domes. The 39 screws on the back of the module apply the pressure that holds the membrane sheets together, so all of them need to be refitted evenly.

ADB

The M2980 is an encoded ADB device, and keyboards default to ADB address $02. All devices on one bus together may draw no more than 500 mA, cables should be no longer than 5 m, and Apple does not recommend daisy-chaining more than three devices on one ADB port. Do not unplug or plug in an ADB device while the computer is running. See Apple Desktop Bus for the protocol.

Maintenance and repair

Identify the variant first

Count the screws in the bottom of the case and look at the dome colour under a removed keycap. Keycaps and membranes do not swap between the variants.

Dead key or dead patch

1. On the Alps membrane-dome variant, check that all 39 module screws are present and evenly tight.
2. Open the keyboard and check the membrane traces from the key pad to the tail connector for continuity.
3. A broken trace can be bridged with conductive silver paint. Clean the area with isopropyl alcohol, let it dry, build the bridge in thin coats and check its resistance before reassembly.
4. A whole dead row or column is a matrix line: follow it back to the tail connector and check the connection there.

Cable fault

The cable is fixed. Check each conductor for continuity while flexing the cable at the case entry. Repair with a splice and heat-shrink and a new strain relief, or replace the cable at the PCB keeping the same pinout.

Soft or sticking keys

Worn or torn domes. On the Alps membrane-dome variant the domes are loose and can be replaced individually.

See also

• Apple Extended Keyboard II
• Apple Adjustable Keyboard
• Apple Desktop Bus
• Retrobrite