Keysight N9038A Service Guide

372 Keysight N9038A MXE Service Guide
Power Supply & Midplane
A6 Power Supply Assembly Troubleshooting
boot-up. Once this output goes to a TTL high level the instrument
CPU will start its boot-up process and the POWER_ON_L line coming
from the A4 Processor assembly will go to a TTL low level which will
tell the A6 Power Supply assembly to turn on the rest of it output
voltages.
If the A6 Power Supply assembly is suspected of causing the
instrument to not power on properly the status of this output can be
verified by either measuring the voltage level at Test Point 506 on the
A7 Midplane board assembly or by viewing the status of the
POWER_OK LED. See the A7 Midplane Board Assembly
Troubleshooting section in this chapter 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.
FAULT_L
The FAULT_L status output is an indication of whether or not there is
a fault detected by the A6 Power Supply that is keeping it from
powering on properly. If all of the required conditions to turn the A6
Power Supply assembly on properly are being met this status output
line will be at a TTL high level. The conditions that could cause this
status output line to be at a TTL low level include that of an over
current condition, an over voltage condition, and an over
temperature condition. However, there is no way to know at the A6
Power Supply assembly level which one of these conditions may be
the cause of a TTL low level to be on the FAULT_L status output.
While any over voltage or over temperature conditions will most
likely be caused by an A6 Power Supply assembly failure, an over
current condition will most likely be caused by another assembly in
the instrument demanding too much current.
If this output is not at a TTL high level the A6 Power Supply assembly
will not turn its non-standby power supplies on, no matter what the
A4 Processor assembly tells it to do.
If the A6 Power Supply assembly is suspected of causing the
instrument to not power on properly the status of this output line can
be verified by either measuring the voltage level at Test Point 508 on
the A7 Midplane board assembly or by viewing the status of the
FAULT_L LED. See the A7 Midplane Board AssemblyTroubleshooting
section in this chapter 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.

Keysight N9038A Specifications

General

Brand	Keysight
Model	N9038A
Category	Measuring Instruments
Language	English