8-8 Service Guide
Receiver Troubleshooting 8719ET/20ET/22ET
At Least One Signal Path Looks Normal 8719ES/20ES/22ES
RF Network Analyzers
A and B Sampler Check by Substitution
1. For the 8719ET/ES and 8720ET/ES, set the output power to −10 dBm by pressing
.
2. For the 8722ET/ES, set the output power to −15 dBm by pressing .
For ES Models, set up the following
3. Connect an RF flexible cable from the output of the transfer switch (A74) directly to the
2.4 mm RF INPUT (J2) of the suspect sampler. Use 3.5 mm to 2.4 mm adapters where
necessary. This connection bypasses the step attenuator, bias tee, and the coupler.
IMPORTANT To disconnect the semirigid cable of the A74 transfer switch, it may be
necessary to disconnect additional semirigid cables and loosen the transfer
switch. Be careful not to damage the center pin when disconnecting the cable.
For ET Models, set up the following
4. For standard ET models, connect an RF flexible cable from the cable (W76) that
connects the MADS (A58) to the directional coupler (A62) to the 2.4 mm RF INPUT (J2)
of the suspect sampler. (Make the connection at the coupler end of the cable.)
For ET Option 004 models, connect an RF flexible cable from the cable that connects the
MADS (A58) to the step attenuator (A69) to the 2.4 mm RF INPUT (J2) of the suspect
sampler. (Make the connection at the attenuator end of the cable.)
5. Connect the IF output cable for the R sampler, to the IF Output of the suspect sampler.
Checking the Operation of the Sampler
6. Press and see whether the instrument phase
locks. Disregard the trace.
• If the instrument phase locks and no error message is displayed, the sampler under
test is normal. Go to “2nd Converter Check” on page 8-9.
• If the instrument displays the PHASE LOCK CAL FAIL error message, either the
sampler or its control and bias voltages are faulty. Continue with “Sampler Voltage
Check.”
Power −10 x1
Power −15 x1
Preset
Preset
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