Keysight Technologies X Series Service Manual page 228

RF Section Troubleshooting (Millimeter-Wave Analyzers)
Troubleshooting
A9 Input Attenuator A and A10 Input Attenuator B Verification
Calibrator Switch Test
On the A16 Reference assembly, disconnect semi rigid cable W19 from
A16J701 and measure A16J701 with a spectrum analyzer. Expected signal is
4.8 GHz at −28 dBm ± 0.5 dB. If signal level is incorrect, suspect A16 Reference
Assembly.
To verify calibrator switch operation, connect external signal source set to
4.8 GHz and −25 dBm to the RF input connector of analyzer under test. Press
Input/Output, RF Calibrator, Off. If the signal level at the attenuator output is
now correct, suspect the A9 Attenuator cal switch or a faulty control signal
from the A15 Front End Controller assembly.
Attenuation Check
Set the signal source connected to the analyzer input port to 0 dBm. On the
analyzer, press Amplitude, Attenuation, and change input attenuation to 0 dB.
The measuring spectrum analyzer connected to A10 Attenuator output port
should indicate a 0 dBm level. Change the input attenuation on the analyzer
under test to 2 dB (if Option FSA is present), or to 10 dB (if Option FSA is not
present).
See the chart below for expected measurement values at the A10 Attenuator
output port.
228
Analyzer Under Test
Attenuator Setting (dB)
0
a
2
a
4
a
6
a
8
10
20
30
40
50
60
70
a. These settings only available if Option FSA is installed.
Power at A10 Output Input Attenuator Being
Port (dBm) Tested
0 dBm (reference)
−2
−4
−6
−8
−10
−20
−30
−40
−50
−60
−70
Keysight N9010A EXA Service Guide
Both set to through path
A9
A9
A9
A9
A10
A10
A10
A10
A10
A10
A9 set to 10 dB,
A10 set to 60 dB