Keysight Technologies N5247B, Service Manual

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Keysight N5247B Service Guide 4-49
Troubleshooting
Measurement System Troubleshooting
Checking Port 1, 2, 3, or 4 Power Outputs (A, B, C, or D Signals)
The object of this check is to verify the power of the output signal across the
entire frequency range. Perform this test if there is an observed problem only
with one receiver trace. The ten second sweep is slow enough to allow you to
observe the output power on the power meter as the sweep occurs.
1. Connect the power sensor to the suspect port.
2. Set the trace to measure S
11
, S
22
, S
33
, or S
44
, dependent on the suspect
port.
3. Observe the power reading on the power meter as the sweep occurs on
the analyzer.
4. The measured output power on the power meter should be at least the
preset power level ±1 dB over the entire frequency range.
— If the measured power is correct, go to “Checking the Receiver
Group” on page 4-52 .
— If the measured power is not correct, go to “Checking the Signal
through the Signal Separation Path” on page 4-49 .
Checking the Signal through the Signal Separation Path
For all of the following checks, refer to the block diagrams at the end of this
chapter and to any of the following that are appropriate:
— “2-Port Configurations, Serial Number Prefixes <6021” on page 6-31
— “4-Port Configuration, Serial Number Prefixes <6021” on page 6-84
— “2-Port Configurations, Serial Number Prefixes
≥
6021” on page 6-58
— “4-Port Configurations, Serial Number Prefix
≥
6021” on page 6-136
Trace loss in the signal separation group is due to one or more of the following
assemblies being defective:
— A50, A51, A52, or A53 mechanical switch and A54 combiner (A54 is only
available in 4-port models with Option 423 and 2-port models with Option
224.)
— A29, A30, A31, or A32 reference coupler
— A38, A39, A40, or A41 source step attenuator
— A42, A43, A44, or A45 bias tee
— A33, A34, A35, and A36 test port coupler