Chapter 1 55
Troubleshooting
Isolating an RF, Analog IF, Digital IF, Reference, Synthesizer, or CPU Problem
Once the boot process is complete, the instrument runs the auto-align
procedure documented on page 32.
If the instrument does not boot, look to see if the LEDs on the processor
are flashing. When the instrument power is turned on, you can observe
the processor LEDs from the rear panel access holes by the LAN
connector as indicated in Figure 1-15. Upon power-up, the green LEDs
will flash on and off as the instrument steps through the boot-up
sequence. At the end of the sequence, all of the green LEDs should be
off. If one or more of the green LEDs remains on, suspect the processor
assembly as being defective. If a LAN cable is attached, it is normal for
the yellow LEDs to flash indicating LAN activity. If a LAN cable is
attached the link integrity LED will also light up.
Figure 1-15 Processor LEDs
If the screen remains blank (dark) and the green LEDs never blink, the
instrument was not able to boot from bootrom. Bootrom on the A22
processor assembly could be bad, or the instrument clock signals could
be missing. The bootrom is not a replaceable part.
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