Front Panel; Hard Disk Drive - Keysight 8990B Service Manual

2 Theory of Operation

Front Panel

The front panel keyboard has a breakaway section that interfaces to the keyboard.
This breakaway section receives the power supply nets from the acquisition board.
The keyboard links to the PC motherboard through a high-speed USB 2.0
interface. The on-board USB hub serves the PIC microcontroller, touch screen
controller board, and up to three front panel USB connectors as user's
peripherals.
A conductive element on the inside of each key shorts a gap on the underlying
keyboard circuit board. The keyboard controller detects this short and sends the
proper keypress information to the system controller on the motherboard.
There are 12 knobs located on the front panel.
Option U02 is not integrated with the three front panel USB connectors.
NOTE

Hard Disk Drive

The hard disk drive is a high-capacity and shock-resistant unit. It is used to store
the peak power analyzer operating system and certain system configuration data.
The hard disk drive can also be used to store and recall the peak power analyzer
setups and waveforms.
60 Keysight 8990B Service Guide