248
Analog/Digital IF Troubleshooting
25 MHz BW IF Section
12.The analyzer should read 22.5 MHz at −25 dBm ± 4 dB as shown in Figure
6-8.
Figure 6-8 A3 Digital I.F. Input
If the 22.5 MHz signal is not measuring the correct power level, see “A2
Analog I.F. Troubleshooting” on page 236 in this service guide.
Verifying the 10 MHz Reference Input
1. Perform an instrument shut down.
2. Remove the cover of the analyzer. Refer to Chapter 14, “Assembly
Replacement Procedures”, on page 435 in this service guide.
3. Turn the instrument over so that the bottom is facing up.
4. Turn on the analyzer and wait for the instrument to complete the boot up
process.
5. Press System, Alignments, Auto Align, Off.
6. Press Input/Output, RF calibrator, 50 MHz.
7. Verify the 50 MHz signal is at −25 dBm by pressing FREQ, 50 MHz, SPAN,
1MHz, Peak Search on the analyzer. The marker readout should be 50
MHz at −25 dBm ± 3 dBm. If this reference signal is measuring incorrectly,
see Chapter 4, “RF Section Troubleshooting”, on page 137 in this service
guide.
8. To continue verifying press SPAN, Zero Span. Verify the input attenuator
on the analyzer is set to 10 dB. (Look near the top of the display near the
center and verify Atten: 10 dB)
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