A And B Sampler Check By Substitution - Agilent Technologies 8719ET Service Manual

Receiver Troubleshooting
At Least One Signal Path Looks Normal

A and B Sampler Check by Substitution

1. For the 8719ET/ES and 8720ET/ES, set the output power to −10 dBm by pressing
−10
Power x1
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
PRESET: FACTORY
Preset
locks. Disregard the trace.
• If the instrument phase locks and no error message is displayed, the sampler under
test is normal. Go to
• If the instrument displays the PHASE LOCK CAL FAIL error message, either the
sampler or its control and bias voltages are faulty. Continue with
Check."
8-8
.
Preset
"2nd Converter Check" on page
Power
and see whether the instrument phase
8-9.
8719ET/20ET/22ET
8719ES/20ES/22ES
RF Network Analyzers
−15
.
x1
"Sampler Voltage
Service Guide