194 Keysight N9038A MXE Service Guide
RF Preselector Section
RF Preselector Section Troubleshooting
A22 Radiated Filter Assembly
The A22 Radiated Filter assembly is responsible for providing the RF
preselector filtering for frequencies between 30 MHz and 3.6 GHz. Each of the
filter paths, as well as any through paths, will be verified in this section.
However, before verifying the operation of any of the filter paths the assembly
initialization will need to be verified.
There are also a number of status LEDs that can be monitored to get an
indication of the status of the assembly.
Assembly Initialization
Before the A22 Radiated Filter assembly will function properly it needs to
initialize itself when the instrument is turned on and be recognized by the
instrument software. The first step in verifying that this has happened is to look
at the instrument Hardware Information screen. To view this information press
System, Show, Hardware. Once you do this you will see a listing of instrument
hardware assemblies that are installed. The A22 Radiated Filter assembly
should identify itself on this list as RF Presel Radiated Filter. If this assembly
does not identify itself the cause for this will need to be determined before any
other troubleshooting is performed. The most probable causes for this type of a
problem would be:
— FPGA Code on the assembly is corrupt
Solution: Reload the FPGA code. See “FPGA Synchronization” in
Chapter 19, “Post-Repair Procedures”.
— An instrument power supply voltage is not operating properly
Solution: Verify all instrument power supply voltages. See Chapter
12, “Power Supply & Midplane”.
— A22 Radiated Filter assembly is defective
Solution: Replace the A22 Radiated Filter assembly
Assembly Status LEDs
There are six diagnostics LEDs visible on the A22 Radiated Filter Assembly, as
shown in Figure 5-20. Table 5-7 lists the diagnostic LEDs and what their status
indicates.
Refer to Chapter 15, “Block Diagrams.”.
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