Keysight Technologies N5224A, Service Manual

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Keysight N5224A/25A Service Guide 4-35
Troubleshooting
Measurement System Troubleshooting
Too many sections! Equipment Setup
1. Before starting these checks, zero and calibrate the power meter. (See the power
meter user’s guide for instructions on setting the calibration factor.)
2. If the
Receiver Display
(
Figure 4-7
or
Figure 4-8
) is not on the analyzer screen,
perform the following: Press UTILITY , then , then ,
then .
3. Set the sweep speed for a 10 second sweep: Press STIMULUS , then
. Set the time to 10.000 seconds in the
Sweep Time
box.
To isolate a broadband RF signal generation failure, check the test port output power:
1. Note the power reading displayed on the power meter; it should be the preset
power level +/- 1 dB.
2. Connect the power sensor, in turn, to Ports 2, 3, and 4 and set trace to measure
S22, S33, and S44 respectively. Note the power reading displayed on the power
meter.
— If the power level is low or high on all test ports, the problem is LO signal related.
Continue with
“Checking the A14 50 MHz Reference Outputs”
.
— If the power level is low or high on only one of the test ports, the problem is either
source group or in the signal separation group. Continue with
“Checking the A14
50 MHz Reference Outputs”
to check the source group.
Checking the A14 50 MHz Reference Outputs
1. Refer to the block diagram at the end of this chapter and to “Top
Assemblies and Cables, All Options” on page 6-16 . Locate flexible cables
W75, W76, and W77, at the A14 frequency reference board.
2. Disconnect cables W75, W76, and W77, one at a time, from the A14
board.
3. Connect the spectrum analyzer to the open connector on the A14 board.
4. The spectrum analyzer should measure a signal at 50 MHz.
5. If any of the 50 MHz signals are not present, replace the A14 frequency
reference board. Refer to “Removing and Replacing the A4–A17 Boards”
on page 7-14 .
6. If the 50 MHz signals are present, reconnect the cables, and then:
— for LO related problems, continue testing at “Checking the A15 13.5
GHz LO Synthesizer Output” .
— for source related problems, continue testing at “Checking the A4
and A17 Source Synthesizer Outputs” on page 4-37 .
System
Service Utilities
Receiver Display
Sweep
Sweep Time