Keysight Technologies N5224A Service Manual page 108

Troubleshooting
Measurement System Troubleshooting
Checking the A15 13.5 GHz LO Synthesizer Output
1. Refer to the block diagram at the end of this chapter and to
Assemblies and Cables, All Options" on page
cable W51 at the A15 LO synthesizer board.
2. Disconnect W51 from J1207.
3. Connect the spectrum analyzer to J1207.
4. Refer to Note on
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 LO signal is not present but the 50 MHz reference signal from
"Checking the A14 50 MHz Reference Outputs"
LO synthesizer board. Refer to
Boards" on page
7. If the signal is present, reconnect cable W41, and then continue with
"Checking the A25 HMA26.5
Checking the A25 HMA26.5 Output
1. Refer to the block diagram at the end of this chapter and to
Assemblies, Standard 4-Port Configuration, Option 400" on page
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
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.
4-36
page 4-28. Set the network analyzer for an 800 MHz CW
"Removing and Replacing the A4–A17
7-14.
Output".
page 4-28. Set the network analyzer for an 800 MHz CW
Keysight N5224A/25A Service Guide
"Top
6-16. Locate the flexible
is present, replace the A15
"Bottom
6-54.