4-36 Keysight N5227B Service Guide
Troubleshooting
Measurement System Troubleshooting
4-
Checking the A14 50 MHz Reference Outputs
1.
Refer to the block diagram at the end of this chapter and to
All Cables—All Options” on page 6-20
. 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
.
6.
If the 50 MHz signals are present, reconnect the cables, and then:
—
for LO related problems, continue testing at
.
—
for source related problems, continue testing at
and A17 Source Synthesizer Outputs” on page 4-38
.
Checking the A15 13.5 GHz LO Synthesizer Output
1.
Refer to the block diagram at the end of this chapter and to
All Cables—All Options” on page 6-20
. 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 Note on
. 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 LO signal is not present but the 50 MHz reference signal from
“Checking the A14 50 MHz Reference Outputs”
is present, replace the A15
LO synthesizer board. Refer to
“Removing and Replacing the A4–A17
.
7.
If the signal is present, reconnect cable W41, and then continue with
“Checking the A25 HMA26.5 Output”
.
