Keysight N5227B, Service Manual

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Keysight N5227B Service Guide 4-37
Troubleshooting
Measurement System Troubleshooting
Checking the A25 HMA26.5 Output
1. Refer to the block diagram at the end of this chapter and to “Bottom RF
Cables, Standard 4-Port Configuration, Option 400” on page 6-65 . Locate
the flexible cable W52 at the A25 HMA26.5.
2. Disconnect W52 (4-port models) or W80 (2-port models) from the A25
HMA 26.5.
3. Connect the spectrum analyzer to the open connector on the A25 HMA
26.5.
4. Refer to Note on page 4-29 . 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.
5. If the observed problem was frequency banded rather than broadband
related, set the analyzer frequency to the center of the problem band. The
spectrum analyzer should measure a signal above the network analyzer
setting. For analyzers with DSP version 4.0, the signal is 7.61 MHz above
the network analyzer setting. For analyzers with DSP version 5.0, the
signal is 7.44 MHz above the network analyzer setting.
6. If the signal is not present but the signal from “Checking the A15 13.5 GHz
LO Synthesizer Output” is present, replace the A25 HMA 26.5. Refer to
“Removing and Replacing the A25 HMA26.5” on page 7-35 .
7. If the signal is present, reconnect cable W52 or W80 and then:
— for 2-port models, continue checking with “Checking the Receiver
Group” on page 4-46 .
— for 4-port models, continue checking with “Checking the A26
Splitter Output” .
Checking the A26 Splitter Output
1. Refer to the block diagram at the end of this chapter and to “Bottom RF
Cables, Standard 4-Port Configuration, Option 400” on page 6-65 . Locate
the semi-rigid cables W53 and W54, at the A26 splitter.
2. Disconnect W53 and W54, one at a time, from the A26 splitter.
3. Connect the spectrum analyzer to the open connector.
4. Refer to the Note on page 4-29 . 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.
5. If the observed problem was frequency banded rather than broadband
related, set the analyzer frequency to the center of the problem band. The
spectrum analyzer should measure a signal above the network analyzer