
Troubleshooting and Block Diagrams 8712ET/ES and 8714ET/ES
Category 2 Failures: No Error Messages but One or More Measurements Are Nonfunctional RF Network Analyzers
4-20 Service Guide
Steps Associated with Figure 4-5
1. Connect a thru cable between RF OUT and RF IN.
2. Press .
3. Observe the traces at each detector and compare to the normal signal trace levels in
Figure 4-5. Press in the menu. For narrowband traces,
press and , , or keys. For broadband detectors,
press and the or keys.
Figure 4-5
NOTE The following troubleshooting descriptions are for the ET models that include
the attenuator (Option 1E1). However, this troubleshooting section can also
be applied to the standard ET analyzers. For a standard ET analyzer, the A
coupler and R coupler functions are combined into one dual directional
coupler.
Symptom 1: Trace at ± 200 dB
A flat trace at ±200 dB indicates that the Digital Signal Processing (DSP) circuit is not
getting data (zero data).
1. Check the connections; make sure the receiver and the CPU board are making good
solid contact to the backplane connectors.
2. If the boards are firmly connected, the problem is most likely the DSP circuit on the
CPU board or the ADCs on the receiver board. To determine the exact cause of failure,
perform the steps in “Testing the DSP Circuit” on page 4-21.
MEAS 1
MEAS 1
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