Keysight Technologies X Series Service Manual page 199

RF Section Troubleshooting (RF/Microwave Analyzers)
Troubleshooting
A12 YTF Preselector Power Level Verification
Press Input/Output, RF Calibrator, 4.8 GHz, AMPTD, Attenuation, 10 dB,
SPAN (X Scale), Zero Span on the analyzer. Measure the 4.8 GHz calibrator on
the output of either the W7 (or, if the microwave preselector bypass hardware
is installed, W34) cable using a functioning spectrum analyzer. When the
4.8 GHz calibrator signal is used, there will be ~ 5 dB (~8 dB if microwave
preselector bypass hardware is installed) ± 4 dB of insertion loss through the
YTF Preselector. The tolerance is large because the A12 YTF loss varies
between devices, and the YTF might not be perfectly aligned, or the frequency
response adjustment may be required.
If the signal level is incorrect, and Option MPB, Microwave Preselector Bypass
is installed and licensed, press AMPTD, More, uW Path Control, uW
Preselector Bypass. If the signal level is now ~ − 51 dBm ± 4 dB as shown in
Figure
To perform the YTF alignment, reconnect W7 or W34 and press System,
Alignments, More, Ad vanced, Characterize Preselector. The routine may take
several minutes to align the YTF. Display the 4.8 GHz calibrator on screen as
explained in the quick check section. If the signal level is still incorrect, suspect
all assemblies, cables, and switches between the W7 (or W34) cable and the
output of the A11 Low Band Switch.
Reconnect W7 and W8 cables (or W31 and W34 cables).
Figure 4-36 4.8 GHz Calibrator Signal at Output of W7 Cable
If the power level is incorrect, the most probable cause is the YTF Preselector.
Reconnect W7 and W8 cables (or W31 and W34 cables).
Keysight N9010A EXA Service Guide
4-36, suspect the A12 YTF is either out of adjustment or faulty.
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