A4 Processor Description; Disk Drive; A4A1 Disk Drive Interface Board; Front Panel Interface - Keysight N8973B Service Manual

CPU/Disk Drive Troubleshooting

A4 Processor Description

A4 Processor Description

If the A4 Processor assembly is suspect in an instrument failure, a full
description of the instrument boot process is described in
and Initialization

Disk Drive

The A5 Disk Drive can easily be removed from the A4 Processor assembly
without removing any of the instrument covers. The disk drive is attached to a
tray that is accessed on the rear panel by loosening one screw and pulling the
drive out of the processor assembly.
If the A4 Processor assembly is replaced, the existing A5 Disk Drive must be
transferred to the replacement Processor assembly.
The A5 Disk Drive is field replaceable. See
the correct replacement part number.

A4A1 Disk Drive Interface Board

There may be situations where the A5 disk drive must be removed and inserted
many times, such as in a security sensitive environment. Therefore, the A4A1
disk drive interface board can be replaced if connector wear is an issue. See
Chapter 14, "Replaceable Parts"

Front Panel Interface

The instrument USB bus is the electrical interface to the instrument front
panel. One of the USB ports on the host controller located on the A4 Processor
assembly is routed to the A1A2 Front Panel Interface board for this use. This
port is a High Speed USB 2.0 compliant port.

Graphics Controller

The entire graphics subsystem is contained within the instrument system
processor chipset. There are multiple outputs of the graphics controller that
are used by the instrument. One provides the LVDS video control to drive the
internal instrument LCD display, one supplies the analog signals to the rear
panel VGA output, and one provide the display data to the rear panel
DisplayPort connector, which can be used to drive multiple external display
types.

Power Supply Control

The power control line from the front panel momentary power switch connects
to the A4 Processor assembly. When the front panel power switch is pressed
the A4 Processor assembly tells the A6 Power Supply assembly to turn on.
Once the +12V D, +5.1V D, and +3.35V D supplies are all on and within
292
Troubleshooting".
for the correct replacement part number.
Keysight NFA Series Noise Figure Analyzers Service Guide
Chapter 2, "Boot Up
Chapter 14, "Replaceable Parts" for