Keysight N9038A, Service Manual

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Keysight N9038A MXE Service Guide 265
L.O. Synthesizer
A14 L.O. Synthesizer Assembly Troubleshooting
Assembly Status LEDs
There are three assembly status indicating LEDs on the A14 LO Synthesizer
assembly, the location of which are shown in Figure 7-1 . When the instrument
is functioning properly all of these LEDs should be off.
To put the instrument into a known state in which all LEDs should be off tune
the instrument to a Center Frequency of 50 MHz and set the Span to 0 Hz. At
this point all of the LEDs should be off. If any of the LEDs are on see Table 7-2
for a possible cause.
Table 7-2 A14 L.O. Synthesizer Assembly Status LEDs
LED Description Cause for Fault
DS1 FPGA Programming Done FPGA code is not uploading from assembly EEROM. Try reprogramming
FPGA by using the “FPGA Synchronization” instructions in Chapter 19,
“Post-Repair Procedures.” . If this LED is on the state of all other LEDs can
be ignored
DS2 Cycle Slipped If DS3 is also on at the same time the status of this Led can be ignored
and troubleshoot the DS3 LED. If this LED is intermittently on by itself it
may not be a problem.
DS3 Frequency Unlocked Verify that the 4800 MHz reference signal from the A16 Reference
assembly is of the correct frequency and power level (See Chapter 9,
“Reference Assembly.” .)