Keysight N9038A Service Guide

Keysight N9038A MXE Service Guide 371
Power Supply & Midplane
A6 Power Supply Assembly Troubleshooting
A6 Power Supply Assembly Troubleshooting
The A6 Power Supply assembly is serviced as an assembly only; no component
level repair is supported.
If the instrument will not boot up properly, or the display is not turning on, refer
to the “MXE Instrument Boot Up Process” on page 39 before further A6 Power
Supply troubleshooting to rule out any other assembly as the cause of the
failure.
Supply Voltages
While there are no test points or status LEDs accessible for troubleshooting on
the A6 Power Supply assembly, there are both test points and status LEDs for
all of the different power supply voltages, as well as other power supply status
lines, on the A7 Midplane Board assembly. See the A7 Midplane Board
Assembly section in this chapter for detailed information on the location of
each.
Control Inputs
POWER_ON
POWER_ON is a signal that when pulled low tells the A6 Power
Supply assembly to turn on all of its outputs. This signal comes from
the A4 Processor board assembly and is initiated by pressing the front
panel power button.
If the instrument will not turn on be sure that this line is being pulled
low by either measuring the voltage level at Test Point 518 on the A7
Midplane board assembly or by viewing the status of the
POWER_ON_L LED. See the "A7 Midplane Board Assembly
Troubleshooting" on page 375 for detailed information on the
location of this test point and LED as well as the expected status for
both when the instrument is operating properly.
Status Outputs
POWER_OK
The POWER_OK status output is an indication of whether or not all of
the digital power supply voltages are up to their specified voltage
levels or not. If all of these supplies are working properly this output
line will be at a TTL high level. If this output is not at a TTL High level
the instrument CPU will not come out of its reset state and will not
The A6 Power Supply has no user replaceable fuse. While there is a fuse internal to the supply
this is not meant for field replacement. If the internal fuse is blown, the power supply has
experienced a major failure and should be replaced.

Keysight N9038A Specifications

General

Brand	Keysight
Model	N9038A
Category	Measuring Instruments
Language	English