Keysight Technologies N9030B Service Manual page 221

Front End Control Troubleshooting
A15 Front End Control Assembly Troubleshooting
functioning spectrum analyzer if the Front End Controller board is switching
this level correctly. If -23 dBm is not being measured correctly, remove the
cable labeled J902 from the Front End Controller board and measure the
output of that cable. This should also measure 322.5 MHz at ~-23 dBm. If the
output of the J902 cable measures correctly and yet the output of J900 is
incorrect, the most probable cause is the A15, Front End Controller board.
Reconnect all cables to their correct location when finished with the
measurements.
When plugging in an mmcx connector, a distinct "snap" should be heard
IMPORTANT
when the cable is seated correctly.
Verifying Wideband IF Out (A15J901, Option B40 or B1X only)
The outer cover and top shield need to be removed to verify A15J901 output.
Refer to Chapter 16, "Assembly Replacement Procedures" for the removal
procedure. Press Mode, IQ Analyzer (Basic), Mode Preset on the analyzer.
Press Input/Output, RF Calibrator, 50 MHz, Freq, 50 MHz, Amptd,
Attenuation, 10 dB, Amptd, More 1 of 2, Internal Preamp Off, System,
Alignments, Auto Align, Off. Disconnect the cable marked J901 that plugs
into the Front End Controller board and connect a functioning spectrum
analyzer where the cable was plugged in. J901's I.F. output will vary
depending on the I.F. path that is chosen. Press Mode Setup, IF Path and
select 40 MHz. If the switch path is working correctly in the A15 Front End
Controller board, the functioning spectrum analyzer should measure 250 MHz
at ~-30 dBm.
If Option B1X is installed in the analyzer press Mode Setup, IF Path and select
140 MHz. If the switch path is working correctly in the A15 Front End Controller
board, the functioning spectrum analyzer should measure 300 MHz at ~-30
dBm.
In order for these I.F. levels to measure correctly, the I.F. input at A15J902
must be correct. Refer to Chapter 4, "RF Section Troubleshooting
(RF/Microwave Analyzers)". Reconnect all cables to their correct location
when finished.
Verifying Aux IF Out, Rear Panel (Option CR3, CRP, ALV only)
The Aux I.F. output connector on the rear panel of the PXA is installed on each
instrument; however the actual Aux I.F. output frequency will vary depending
on the options installed. These options are all enabled with a license key. The
first step in verifying the Aux I.F. output is the make sure the option is licensed
by pressing System, Show System on the analyzer and make sure the option
identifies itself in the table.
N9030B PXA Signal Analyzer Service Guide 221