Keysight Technologies N5221A, Service Manual, Page: 111 / 368

Keysight N5221A/22A Service Guide 4-37
Troubleshooting
Measurement System Troubleshooting
6. If the signal is not present and the signal is present from “Checking the
A11 13.5 GHz LO Synthesizer Output,” replace the A21 HMA 26.5. Refer to
“Removing and Replacing the A21 HMA26.5” on page 7-33 .
7. If the signal is present, reconnect cable W42 or W70, and then:
— for 2-port models, continue checking with “Checking the Receiver
Group” on page 4-43 .
— for 4-port models, continue checking with “Checking the A22
Splitter Output” .
Checking the A22 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 6-56 . Locate
the semi-rigid cables W43 and W44, at the A22 splitter.
2. Disconnect W43 and W44, one at a time, from the A22 splitter.
3. Connect the spectrum analyzer to the open connector.
4. Refer to Note on page 4-28 . 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 and the signal is present from “Checking the
A21 HMA26.5 Output,” replace the A22 splitter. Refer to “Removing and
Replacing the A22 Splitter” on page 7-35 .
7. If the signal is present, reconnect cables W43 and W44, and then continue
with “Checking the Receiver Group” on page 4-43 .
Checking the A4 and A13 Source Synthesizer Outputs
1. Refer to the block diagram at the end of this chapter and to “Top Cables,
All Cables—All Options” on page 6-19 . Locate either the flexible cable W1
at the A4 source 1 synthesizer board or W2 at the A13 source 2
synthesizer board. (W2 and A13 are only available in 4-port models and
2-port models with Option 224.)
2. Disconnect W1 or W2 from J1207.
3. Connect the spectrum analyzer to J1207.
4. Set the network analyzer for a 800 MHz CW frequency and observe the
spectrum analyzer measurement. The spectrum analyzer should measure
a signal at 800 MHz.