160 Keysight N9038A MXE Service Guide
Input Selection & Level Control
Input Selection & Level Control Section Troubleshooting
3. Referring to Figure 4-20, disconnect W30, W31, W36, and W37 from the
SW2 Transfer Switch.
4. Turn the instrument on and allow it to complete its boot up process,
ignoring any error messages.
5. Turn the instrument self-alignment routine off by pressing System,
Alignments, Auto Align, Off.
6. Connect a signal generator to the SW2 Transfer Switch RF Input (P1), as
shown in Figure 4-21.
7. Tune the signal generator to 100 MHz with an amplitude of −20 dBm.
8. Connect a spectrum analyzer to the SW2 Transfer Switch RF Output (P4),
as shown in Figure 4-21.
9. Tune the spectrum analyzer to 100 MHz with a span of 1 MHz.
10.Switch the instrument to bypass the RF preselector, which will connect
the SW2 Transfer Switch RF Input (P1) to the RF Output (P4), by pressing
Input / Output, RF Input, RF Preselector Off.
11.Verify that the signal level on the spectrum analyzer is at −20 dBm
(±0.25 dB), as shown in Figure 4-24, allowing for any additional test cable
loss.
If the signal level is incorrect the most likely cause of the problem is the
SW2 Transfer Switch itself. However, before replacing an SW2 Transfer
Switch for any failure, refer to the “A21 RF Preselector Input Assembly”
section on page 175 for information on how to verify the control signals to
it.
In order to not bend the semi-rigid cables it may be necessary to remove some of them from the
other end as well.
If there is a particular frequency of interest use that instead of the 100 MHz used in this example.
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