
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
4-18 Service Guide
Category 2 Failures: No Error Messages but One or
More Measurements Are Nonfunctional
This section is divided into three parts. The first two parts contain separate sections to
troubleshoot the ET and ES analyzers in a step-by-step process. If the step-by-step
procedures are unsuccessful, the third part contains general troubleshooting information.
Category 2 (ET Analyzer Troubleshooting)
This process assumes that a single assembly or part has failed in an otherwise fully
functional ET model analyzer. Go through the numbered symptoms in this section and find
the one that best describes the failure.
The block diagrams in Figure 4-4 and Figure 4-5 show the signal flow through the RF
portion of the receiver assembly, while the shaded area lists the normal signal trace levels
for each detector. These figures apply to symptoms 2 through 9.
Using the figures as a template to troubleshoot
Figure 4-4 and Figure 4-5 assist you in troubleshooting by supplying normal trace levels
that occur for each detector in the open state and with a thru cable attached. Compare the
trace levels for the analyzer under test with the trace levels in the figures and find which
traces or trace are abnormal. Go through the symptoms in the order listed, find the first
symptom that matches the measurement results. Follow the instructions for that
symptom.
NOTE Use these trace definitions when applying the measured results to symptoms
2 through 9:
• For a trace to meet the “Above −10 dBm” trace level, all parts of the trace
must be above −10 dBm.
• For a trace to meet the “Below −10 dBm” trace level, all parts of the trace
must be below −10 dBm.
• For a trace to be considered noisy, the peak to peak noise must be greater
than 5 dB.
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