Keysight U3020AS26, User'S And Service Manual

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32 Keysight U3020A User’s and Service Guide
Front panel input port LEDs
1 If the Input Port LEDs do not operate when you have executed a Port Selection command on
the Test Set continue with the following procedure:
a If you have determined that the RF switch is operating, either by an audible sound or by an
RF Input to Output port measurement, remove the top cover of the instrument.
b Ensure that the two ribbon cables going from the Controller Module I/O port to the front
panel LED board are properly in place.
c Measure the three labeled output power supply voltages on the Controller Module at the
green connector.
d If any voltages are not present, the Controller Module Power Supply will need to be
replaced.
e If the Power Supply voltage are all present, suspect the front panel Input Port LED board or
the Controller Module I/O section.
RF switch is not switching
1 If the RF Switches are not operating continue with the following procedure:
a Determined if you can hear an audible switching sound.
b If an audible sound is heard, but the switch is not being properly control in order for the
correct Port to be selected, it is possible that the instrument Power On preset set has been
corrupted.
c Contact Keysight Technologies for support in recovering this preset set.
d If no audible sound is heard, remove the top cover of the instrument.
e Insure that the ribbon cable connections at the distribution board and switch are properly in
place.
f Measure the three labeled output power supply voltages on the Controller Module at the
green connector.
g If any voltages are not present, the Controller Module Power Supply will need to be
replaced.