Keysight Technologies X Series Service Manual page 249

Front End Control Troubleshooting
A15 Front End Control Assembly Troubleshooting
Disconnect RF Front End Troubleshooting Board
You do not need the RF front end troubleshooting board to test out the
remaining front end hardware components. At this point it is advisable to
shutdown the analyzer and disconnect the test board and cables. Be sure to
reconnect the EXA Low Band switch ribbon cable and the input attenuator
ribbon that were originally plugged into the Front End Control board before
testing the input attenuator and low band switch logic.
Keysight N9010A EXA Service Guide 249