275
Analog/Digital IF Troubleshooting
≥ 85 MHz BW IF Section
A25 Wideband Troubleshooting
Verify the 300 MHz IF Input level
1. Turn the instrument off.
2. Remove the instrument cover. Refer to Chapter 14, “Assembly
Replacement Procedures” in this service guide.
3. Turn on the N9020A Signal Analyzer and wait for the instrument to
complete the boot up process.
4. Press System, Alignments, Auto Align, Off.
5. Press Mode, IQ Analyzer
6. Press Meas, Complex Spectrum
7. Press Input/Output, RF Calibrator, 50 MHz
8. Press Mode Setup, IF Path, 85, 120, or 140 MHz
9. Verify the 50 MHz signal is at −25 dBm on the analyzer display by pressing
FREQ, 50 MHz, SPAN, 1 MHz, Peak Search on the N9020A. The marker
readout should be 50 MHz at −25 dBm ±3 dB. If this reference signal is
measuring incorrectly, see Chapter 4, “RF Section Troubleshooting” in this
service guide.
10.Connect A25J02 to a known good spectrum analyzer. Tune the spectrum
analyzer to 300 MHz.This port switches the 300 MHz IF that is input to the
A25 Wideband Analog IF to be routed to the A3J16 40 MHz Digital IF. If
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