274 Keysight N9038A MXE Service Guide
Front End Control
A15 Front End Control Assembly Troubleshooting
A15 Front End Control Assembly Troubleshooting
Since the A15 Front End Control assembly is responsible for the control of
many different components in the front end of the instrument there are quite a
few different things that will need to be checked to verify that it is functioning
properly. They are:
— Assembly Initialization
— A9 Input Attenuator A Control*
— A10 Input Attenuator B Control*
— A11 RF Switch / High Band Preamp Control*
— A12 YTF Preselector Control*
— A12 YTF Preselector Alignment
— A13 RF Front End Assembly Control*
— IF Switching
— AUX IF Output (Option CR3)
* Can only be verified in instruments with Option 503, 508, or 526.
Assembly Initialization
Before the A15 Front End Control 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 A15 Front End Control assembly
should identify itself on this list as Front End Controller. 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 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.”.
— A15 Front End Control assembly is defective
Solution: Replace the A15 Front End Control assembly
Refer to Chapter 15, “Block Diagrams.”.
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