Editing Apple Extended Keyboard II (section)

== Internal Design ==

=== PCB Architecture ===
'''Controller:''' Toshiba TC4515BP binary controller
* 8-bit microcontroller
* Integrated ADB protocol handling
* Key matrix scanning at 1000 Hz
* Debounce processing

'''Component layout:'''
* Surface-mount technology throughout
* Dual ADB ports on separate daughter boards
* Ribbon cable interconnects
* Component count: ~35 discrete parts

=== Assembly Process ===
# Steel plate preparation and powder coating
# Switch insertion into plate (105 positions)
# PCB alignment and mounting to plate assembly
# Wave soldering of switch pins
# Manual installation of stabilizers
# ADB port PCB installation
# Case assembly (front clips, rear tabs)
# Cable routing and strain relief
# Quality control testing

=== Key Matrix Design ===
* '''Matrix size:''' 8×16 (128 possible positions)
* '''Ghost key prevention:''' Diode per switch
* '''Scan rate:''' 1000 Hz internal, 100 Hz ADB report
* '''Debounce period:''' 5ms typical