Keysight CXG, EXG, and MXG X-Series Signal Generators Service Guide 199
RF Assembly
A3 RF Assembly Troubleshooting
A3 RF Assembly Troubleshooting
A3 RF assembly faults could manifest themselves in a broad range of failure
symptoms. While there are many circuits and multiple sections on the A3 RF
assembly it is very limited in the amount of measurement points for
troubleshooting. This section will address the most common failure symptoms.
To provide access to the internal circuitry required to perform the
troubleshooting procedures in this section the instrument outer cover and
inner top and bottom covers will first need to be removed. Refer to Chapter 15,
“Assembly Replacement,” for instructions on how to remove and reinstall
these covers.
Before replacing the A3 RF assembly be sure to see the “Pre Repair
Procedures” section in Chapter 16, “Pre and Post-Repair Procedures”
Reference Section
The only port that can be used to make a measurement of any of the Reference
section outputs is the rear panel 10 MHz OUT port. As shown in Table 10-4,
this output should be at a level of +4 dBm or greater. It should also always be
at 10 MHz, even if an external reference of a different frequency is being used.
If there is a problem with the Reference section of any sort, including the failing
of a Self Test or a performance verification test, do the following:
1. Verify the power supply voltages by seeing the “Power Supply Status
Quick-Check” section in Chapter 8, “Power Supply”
2. Verify that the instrument is using the factory calibration data by restoring
the data. See “Calibration Data Restore” in Chapter 3, “Instrument
Information and Calibration Data”
3. Run the “Reference Related Adjustments” listed later in this section.
4. If the failure persists, replace the A3 RF assembly.
Reference Unlocked
If there are any reference unlocked errors see the “512 Reference Unlocked”
section in Chapter 6, “Troubleshooting”
External Reference Not Detected
Use the following procedure to troubleshoot a 512 Reference Unlocked error
when using an external frequency reference:
1. Connect a 10 MHz signal with a power level of 0 dBm to the REF IN port on
the rear panel of the instrument. (The power level of the external reference
should be between -3 dBm and +20 dBm.)
2. Force the instrument to use the external reference by pressing FREQ,
More, Reference Oscillator, Ref Oscillator Source, Ext.
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