Service Guide N5227-90001 4-31
PNA Series Microwave Network Analyzers Troubleshooting
N5227A Measurement System Troubleshooting
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:
4. Note the power reading displayed on the power meter; it should be the preset power level +/- 1 dB.
5. Connect the power sensor, in turn, to Ports 2, 3, and 4 and set trace to measure S
22
, S
33
, and S
44
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 Cables, All Cables—All Options” on
page 6-18. 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 7-10
.
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 4-33.
Checking the A15 13.5 GHz LO Synthesizer Output
1. Refer to the block diagram at the end of this chapter and to “Top Cables, All Cables—All Options” on
page 6-18. Locate the flexible cable W51 at the A15 LO synthesizer board.
2. Disconnect W51 from J1207.
3. Connect the spectrum analyzer to J1207.
4. Refer to the IMPORTANT notice on page 4-23. Set the network analyzer for an 800 MHz CW frequency
and observe the spectrum analyzer measurement. For analyzers with DSP version 4.0, an 807.61 MHz
signal should be present. For analyzers with DSP version 5.0, an 807.44 MHz signal should be present.
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