4
Troubleshooting Guide
52
Keysight N1911A/1912A Service Guide
Instrument Self-Test
Instrument
Purpose
Debug tips
Possible faults
Test point voltages
Checks that all of the supply
voltages are present
Replace the PSU to see if this
clears the faults
PSU (low probability)
Main board (high probability)
Calibrator
Verifies that the calibrator is
working
(Note: This test does not check
that the calibrator meets its
specifications)
Check/reseat that cable
between the Calibrator
Assembly and the Main board
Attempt to adjust the 1 mW
Power Reference Level
Calibrator assembly (high
probability)
Main board (low probability)
Fan
Verifies that the fan is working
Check/reseat the cable
between the Fan Assembly and
the Main board
Check visually to see whether
or not the Fan is working
Fan assembly (high probability)
Main board (low probability)
Battery
Checks that the lithium
manganese battery on the
main board is working
Replace the battery to see if
this clears the fault
(Note: It is recommended for
the battery to be replaced at
the Keysight service center
every five years)
Lithium manganese battery
(high probability)
Main board (low probability)
Peak path/ChA peak path
Verifies that the peak path of
channel A is working
(Note: This does not prove that
the peak path meets its
specifications)
Replace the DAP Assembly for
Channel A to see if this clears
the fault
DAP assembly, channel A (low
probability)
Main board (low probability)
CW path/ChA CW path
Verifies that the average path
of channel A is working
(Note: This does not prove that
the average path meets its
specifications)
Not applicable
Main board
DAP check/ChA DAP check
Executes an internal self-test
procedure on the DAP
assembly for channel A
Replace the DAP assembly for
channel A to see if this clears
the fault
DAP assembly, channel A (high
probability)
Main board (low probability)