Editing Apple Desktop Bus Mouse

{{Infobox computer peripheral
| name         = Apple Desktop Bus Mouse
| image        = [[File:Apple_Desktop_Bus_Mouse.jpg|250px]]
| caption      = Apple Desktop Bus Mouse (Model M0142)
| manufacturer = Apple Computer, Inc.
| type         = Pointing device
| release date = September 1986
| discontinued = January 1993
| price        = US$119 (retail)
| interface    = [[Apple Desktop Bus]]
| compatible   = Apple IIGS, Macintosh SE, Macintosh II, all ADB-equipped Macs
| dimensions   = 93 mm L × 61 mm W × 36 mm H
| weight       = 175 g (6.2 oz)
| predecessor  = [[Apple Mouse]] (DE-9)
| successor    = [[Apple Desktop Bus Mouse II]]
| model        = M0142, G5431, A9M0331
}}

The '''Apple Desktop Bus Mouse''' was the first mouse designed for the [[Apple Desktop Bus]] (ADB) interface, introduced in September 1986 with the [[Apple IIGS]]. Released alongside Apple's transition from proprietary connectors to the standardized ADB system, it became the standard mouse for Macintosh computers from the [[Macintosh SE]] and [[Macintosh II]] through early 1993. The mouse retained the angular, blocky design of its DE-9 predecessor but adopted the Snow White design language with uniform Platinum gray coloring.

== Model Variants ==

Three model numbers were assigned to the Apple Desktop Bus Mouse during its production run:

* '''A9M0331''' – Original model introduced with the Apple IIGS (September 1986)
* '''G5431''' – Version bundled with Macintosh II and SE (March 1987)
* '''M0142''' – Consolidated model number used from 1988-1993

Despite different model numbers, all variants were functionally identical. Manufacturing occurred in Taiwan (early models), Ireland, USA, and later Singapore and Malaysia facilities.

== Design & Construction ==

=== Physical Characteristics ===
The ADB Mouse maintained the rectangular footprint of earlier Apple mice but featured a lower, triangular profile measuring 93mm × 61mm × 36mm. The single button spanned the entire front section of the mouse, providing a large clicking surface. The case was injection-molded ABS plastic in Apple's standard Platinum gray (Pantone 423C), with only the cable and connector retaining the darker "Smoke" gray color.

=== Internal Components ===
The mouse utilized mechanical ball tracking with the following key components:

* '''Tracking mechanism:''' 19mm rubber-coated steel ball (black on early models, gray on later)
* '''Optical encoders:''' Two perpendicular slotted wheels with infrared LED/phototransistor pairs
* '''Controller chip:''' Various manufacturers including:
** Mitsumi custom ADB controller
** Logitech 42c60p5625 (Taiwan models)
** IC Designs custom ASIC
** Alps 820-0232 (USA models)
* '''Microswitch:''' Omron D2F series rated for 1 million clicks
* '''Circuit board:''' Single-sided PCB with through-hole components

=== Manufacturing Variations ===
Five primary internal designs existed across production facilities:

'''Taiwan manufacture (Logitech):'''
* Model A9M0331 with black ball
* Beige PCB top, green bottom
* Marked "ADB Mouse by Logitech Rev C2"
* White ball cage
* Part numbers: 400115-400118

'''Taiwan manufacture (Logitech G5431):'''
* Green PCB marked "Logitech AT Rev B"
* P/N 200048-00
* Black ball cage
* Part numbers: 400234-400235

'''USA manufacture (Alps):'''
* Brown PCB stamped 820-0232
* Gray 25mm ball
* Round retainer with V-notch
* Integrated ball cage
* Part numbers: 815-1090 to 815-1092

'''USA manufacture (Unknown):'''
* Green PCB stamped 820-0146
* Gray 25mm ball
* Ribbed retainer with 3 tabs
* White ball cage
* Steel rollers

'''Malaysia manufacture (Mitsumi):'''
* Brown PCB marked Mitsumi
* Gray 25mm ball
* Black ball cage
* Two-screw PCB mounting
* Part numbers: 64-1259 to 64-1262

== Technical Specifications ==

=== ADB Interface ===
The Apple Desktop Bus Mouse communicated using the ADB protocol over a 4-pin mini-DIN connector:

{| class="wikitable" style="width:50%; text-align:center;"
|+'''ADB Connector Pinout'''
! Pin !! Signal !! Description
|-
| 1 || ADB Data || Bidirectional serial data line
|-
| 2 || PSW || Power switch signal (unused on mouse)
|-
| 3 || +5V || Power supply (100mA max draw)
|-
| 4 || GND || Ground reference
|}

=== Communication Protocol ===
* '''Data rate:''' Up to 125 kbit/s theoretical (typically 10-50 kbit/s)
* '''Bit encoding:''' Self-clocking duty cycle modulation
** Logic 0: Low 65μs, High 35μs
** Logic 1: Low 35μs, High 65μs

* '''Default address:''' $3 (reassignable via bus enumeration)
* '''Polling rate:''' ~100 Hz typical

=== Protocol Timing Details ===
Each ADB transaction follows this sequence:
# '''Attention signal:''' Host pulls bus low for 800μs
# '''Sync signal:''' Bus high for 70μs
# '''Command byte:''' 8 bits (4-bit address, 2-bit command, 2-bit register)
# '''Stop bit:''' Logic 0 with optional 300μs service request window
# '''Stop-to-start time (Tlt):''' 140-260μs high period

=== Device Registers ===
The ADB Mouse implemented standard ADB register functionality:

* '''Register 0:''' Mouse movement data (2 bytes)
** Byte 0: Button state (bit 7) + X movement delta (-127 to +127)
** Byte 1: Button state (bit 7) + Y movement delta (-127 to +127)

* '''Register 1:''' Reserved (unused, later used for extended protocol)
* '''Register 2:''' Reserved (unused)
* '''Register 3:''' Device identification and address
** Default handler ID: $01 (standard mouse)
** Bits 11-8: Device address (default $3)
** Bits 7-0: Handler ID

=== Tracking Performance ===
* '''Resolution:''' 100 counts per inch (CPI)
* '''Maximum tracking speed:''' 10 inches/second
* '''Sampling rate:''' Mechanical encoder dependent (~200 Hz)
* '''Encoder wheel slots:''' 36 per wheel (10° resolution)

== ADB System Architecture ==

The Apple Desktop Bus represented a major shift in Apple's peripheral connectivity strategy. Key features included:

* '''Multi-device support:''' Up to 16 devices on a single bus
* '''Daisy-chaining:''' Devices could be connected in series
* '''Hot-swapping:''' Theoretical support (not recommended on most systems)
* '''Power distribution:''' Bus supplied up to 500mA at 5V total
* '''Collision detection:''' Automatic address conflict resolution

The mouse typically operated at address $3, with the keyboard at address $2. During system initialization, the ADB Manager would enumerate devices and resolve any address conflicts through a sophisticated random address generation scheme.

== Expanded Troubleshooting & Repair ==

=== Diagnostic Procedures ===

==== Erratic Cursor Movement ====
'''Symptoms:''' Jumpy, inconsistent, or drifting cursor movement

'''Root Causes & Solutions:'''
# '''Dirty encoder wheels''' (Most common)
#* Remove ball and inspect encoder wheels for dust/debris
#* Clean wheels with cotton swab and 90%+ isopropyl alcohol
#* Use compressed air to clear encoder slots
#* Ensure LED/phototransistor pairs are clean

# '''Worn ball surface'''
#* Check for flat spots or uneven wear
#* Clean ball with isopropyl alcohol
#* Replace if severely worn (19mm rubber-coated steel ball)

# '''Encoder wheel damage'''
#* Inspect for broken or bent encoder wheel teeth
#* Check encoder shaft for excessive play
#* Replacement requires donor mouse or compatible encoder assembly

# '''Controller chip issues'''
#* Test with known-good ADB system
#* Check for proper +5V supply at controller
#* Controller replacement requires exact matching part

==== Button Failures ====
'''Symptoms:''' No click, stuck button, double-clicking, intermittent response

'''Microswitch Testing:'''
# Measure resistance across switch terminals (should be <1Ω when pressed)
# Test for proper tactile feedback and audible click
# Check for mechanical obstruction in button mechanism

'''Replacement Procedure:'''
# Compatible switches: Omron D2F-01, D2F-01F, D2F-01F-T
# Specifications: SPDT, 10mA minimum current rating
# Desolder old switch carefully to avoid PCB damage
# Install new switch ensuring proper alignment with button actuator

==== Complete Failure ====
'''Symptoms:''' No response, system doesn't recognize mouse

'''Systematic Diagnosis:'''
# '''Power verification'''
#* Measure +5V at pin 3 of ADB connector
#* Check ground continuity at pin 4
#* Typical current draw: 50-80mA during operation

# '''Cable testing'''
#* Check for breaks at strain relief points
#* Test continuity of all four wires end-to-end
#* Common failure point: cable entry to mouse body

# '''ADB communication test'''
#* Use oscilloscope to verify data signal on pin 1
#* Check for 800μs attention pulse from host
#* Verify mouse responds with register data when polled

# '''Controller diagnostics'''
#* Check crystal oscillator (if present) for proper frequency
#* Verify controller power pins (+5V and ground)
#* Test for shorts on data lines

=== Component-Level Repairs ===

==== Circuit Board Repair ====
'''Common PCB Issues:'''
* Cracked traces near cable entry
* Cold solder joints on through-hole components
* Corrosion from liquid spills

'''Repair Techniques:'''
* Use 30AWG wire for trace repairs
* Reflow all solder joints with flux
* Clean corrosion with white vinegar, then IPA
* Apply conformal coating after repairs

==== Encoder Maintenance ====
'''Cleaning Procedure:'''
# Remove encoder wheels from shafts
# Clean wheel slots with soft brush
# Clean optical pairs with lens cleaning solution
# Verify proper spring tension on roller shafts
# Apply small amount of silicone lubricant to shafts

'''Alignment Check:'''
* Encoder wheels must be perpendicular
* LED must align with center of phototransistor
* Wheel must pass cleanly through optical gap
* No rubbing or binding during rotation

==== Cable Replacement ====
'''Required Skills:''' Soldering, cable preparation

'''Procedure:'''
# Source replacement 4-conductor cable with shield
# Match original wire colors if possible:
#* Pin 1 (Data): Usually white or yellow
#* Pin 2 (PSW): Usually black or brown
#* Pin 3 (+5V): Usually red
#* Pin 4 (Ground): Usually green or shield
# Maintain original cable length (approximately 1.2m)
# Use heat shrink tubing at stress points

=== Test Equipment & Tools ===

'''Essential Tools:'''
* Digital multimeter with continuity test
* Precision screwdriver set (Phillips #0, #1)
* Desoldering pump or wick
* Temperature-controlled soldering iron (15-25W)
* 90%+ isopropyl alcohol
* Cotton swabs and lint-free cloths
* Compressed air

'''Advanced Diagnostics:'''
* Oscilloscope (10MHz minimum bandwidth)
* Logic analyzer for protocol analysis
* ADB diagnostic software (TechTool, ADB Parser)
* Frequency counter for timing verification

=== Preventive Maintenance Schedule ===

'''Monthly:'''
* External cleaning of mouse surface
* Check cable for damage

'''Quarterly:'''
* Remove and clean ball
* Inspect encoder wheels
* Clean mouse pad surface

'''Annually:'''
* Disassemble and deep clean
* Check microswitch operation
* Inspect PCB for damage
* Test on known-good system

== Common Modifications ==

=== Two-Button Conversion ===
Most ADB controller chips included support for a second button, though Apple never implemented it. Common modifications included:

* Identifying the unused second button pin on the controller chip (varies by manufacturer)
* Adding a tactile switch connected to this pin and ground
* Modifying the case to accommodate the additional button
* Software support via third-party control panels (ClickChange, MouseWorks)

=== Optical Sensor Upgrade ===
Modern retrofit kits allow replacement of the mechanical ball system with optical tracking:

* TT Design's ADB Optical Mouse Retro Board (RP2040-based)
* Uses modern optical sensor (PixArt or similar)
* Maintains original 100 CPI default with adjustable settings
* Compatible with original ADB protocol and timing
* Requires desoldering original PCB and installing retrofit board

=== Performance Enhancements ===
* '''Teflon pad replacement:''' Replace worn pads with PTFE dots
* '''Ball upgrade:''' Replace with precision phenolic resin ball
* '''Spring tension adjustment:''' Optimize encoder wheel pressure
* '''Shielding improvements:''' Add EMI shielding to reduce interference

== Maintenance & Repair ==

=== Cleaning Procedure ===
Regular maintenance was essential for reliable operation:

# Remove the retaining ring on the bottom of the mouse (rotate counterclockwise)
# Extract the tracking ball
# Clean ball with isopropyl alcohol
# Remove lint and debris from encoder wheels using compressed air
# Clean encoder wheel surfaces with cotton swab and IPA
# Clean mouse pad contacts if present
# Reassemble in reverse order

=== Common Failures ===
* '''Erratic cursor movement:''' Dirty encoder wheels or worn ball (80% of issues)
* '''Button failure:''' Worn microswitch (replaceable with D2F series)
* '''Intermittent connection:''' Broken wires at cable strain relief
* '''Complete failure:''' ADB controller chip damage (often from hot-swapping)

=== ADB Port Safety ===
The ADB port lacked proper protection against hot-swapping on most systems. Connecting or disconnecting devices while powered could blow the ADB fuse on the motherboard (typically 1.1A polyfuse), requiring professional repair or fuse replacement.

== Historical Context ==

The Apple Desktop Bus Mouse marked several important transitions:

* '''First ADB peripheral:''' Introduced the new connection standard alongside the Apple IIGS
* '''Design language shift:''' Fully embraced Snow White industrial design
* '''Manufacturing globalization:''' Production spread across multiple facilities worldwide
* '''Extended compatibility:''' Worked with all ADB-equipped systems through 1999

Production estimates suggest over 4 million units manufactured during its 6.5-year production run.

== Software Compatibility ==

=== System Software ===
* '''Apple IIGS:''' GS/OS with built-in mouse driver
* '''Macintosh:''' System 3.2 through Mac OS 9.2.2
* '''NeXT:''' Compatible with ADB-equipped NeXT systems
* '''Third-party:''' MouseKeys, QuicKeys, SteerMouse, USB Overdrive (with adapters)

=== Control Panels ===
* '''Mouse control panel:''' Tracking speed adjustment (System 6.0+)
* '''CloseView:''' Cursor size and visibility options
* '''Third-party tools:''' Added acceleration curves and button customization

== Parts & Specifications ==

=== Replacement Components ===
{| class="wikitable" style="width:70%; text-align:center;"
|+'''Common Replacement Parts'''
! Component !! Specification !! Modern Equivalent
|-
| Microswitch || Omron D2F series || D2F-01F-T, D2FC-F-7N
|-
| Ball || 19mm rubber-coated steel || 3/4" precision bearing ball
|-
| Encoder wheels || 36-slot optical || Custom part (donor required)
|-
| LED || IR 940nm || Standard 3mm IR LED
|-
| Phototransistor || IR sensitive || Standard 3mm phototransistor
|-
| Controller IC || Various proprietary || No direct replacement
|}

=== Electrical Specifications ===
* '''Operating voltage:''' 4.75V - 5.25V
* '''Current consumption:''' 50mA typical, 100mA maximum
* '''Data rate:''' 10-50 kbit/s typical
* '''Temperature range:''' 10°C - 40°C operating
* '''Humidity:''' 20% - 80% non-condensing

== Collector Information ==

=== Identification ===
* '''Early models (1986-1988):''' Larger printed label with two screws
* '''Later models (1988-1993):''' Smaller label with single center screw
* '''Serial number format:''' First letter indicates year, second indicates manufacturing location

=== Condition Assessment ===
* '''Case yellowing:''' Common due to brominated flame retardants in ABS plastic
* '''Cable integrity:''' Check for cracks at strain relief points
* '''Mechanical wear:''' Test ball retention and encoder wheel movement
* '''Button feel:''' Should have distinct tactile feedback

=== Modern Usage ===
* '''ADB-to-USB converters:''' Griffin iMate (discontinued), Wombat adapter, Belkin F5U118
* '''Retrobrighting:''' Possible but risky for painted Platinum plastic
* '''Replacement parts:''' NOS balls and microswitches still available
* '''Modern retrofits:''' Optical sensor upgrades maintain vintage appearance

== Related Accessories ==
* [[Apple Desktop Bus Keyboard]]
* [[Apple Desktop Bus Mouse II]]
* [[Macintosh Mouse Pad]]
* [[ADB Extension Cable]]

== See Also ==
* [[Apple Desktop Bus]]
* [[Apple Desktop Bus Protocol Specification]]
* [[ADB Device Programming]]


{{Navbox-AppleVintageAccessories}}


[[Category:Apple Vintage Accessories]]
[[Category:Apple Desktop Bus]]