178 Keysight Technologies N9040B UXA Signal Analyzer Service Guide
Front End Control Troubleshooting
A15 Front End Control Assembly Troubleshooting
Preselector Tune Output
The J302 connector is a test point used to verify the internal A12, YIG Tuned
Filter drive voltage variations with center frequency. The YTF is used in the
high band path (3.6 GHz to 26.5 GHz). Connect A15J302, Presel Tune to a
voltmeter. Use the MMCX (m) to SMB (f) to connect to J302 on the A15 board
and appropriate adaptors to connect to the voltmeter. Refer to Figure 5-1 for
J302 location. You may also need a Banana plug to BNC (f) adapter, part
number E9637A for the voltmeter. The preselector tune output voltage can be
measured to verify this portion of the A15 is functioning.
Press System, Alignments, Auto Align, and choose Off from the drop-down
menu once it has fully booted to the spectrum analyzer application. Press Freq,
Span and toggle to Zero Span on the analyzer. The preselector tune output
voltage in high band should change when the center frequency of the analyzer
is changed.
Table 5-9 Preselector Tune Output Voltages
(Option 508, 513, 526)
Center Frequency
(GHz)
~ Tune Voltage
(VDC)
Valid Frequency
Range Option
5.0 1.55 508, 513, 526
10.0 3.12 513, 526
15.0 4.7 526
20.0 6.27 526
26.0 8.17 526