186 Keysight NFA Series Noise Figure Analyzers Service Guide
RF Section Troubleshooting (N8973B, 74B, 75B Analyzers)
Troubleshooting
If any of the preselector control currents do not match the levels in Table 4-16,
the most probable causes are a misaligned YTF or the A15 Front End Control
Assembly. Perform the YTF characterization (press System, Alignments,
Ad vanced, Characterize Preselector) and re-check the control current at
various center frequencies.
In order to measure the control current correctly, press Restart on the
analyzer in between each measurement.
Table 4-16 YTF Tune Current
Center Frequency
(GHz)
Control Current
(mA)
Tolerance
(mA)
5.0 106 ±20
10
a
a. N8975B/76B
215 ±25
15
a
324 ±30
20
a
430 ±40
26
a
560 ±50
Tolerances should be used as a guideline. The true test is whether or not
the analyzer will function and meet published specification.
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