Keysight Technologies X Series Service Manual page 245

Front End Control Troubleshooting
A15 Front End Control Assembly Troubleshooting
Input Attenuator A Control Logic Verification (Option 532 or 544)
Ignore DS11 in this procedure.
Press System, Show, Hard ware. Look for an entry for the Low Band Switch
and verify that the HW ID is 45. If the HW ID is something other than 45 (for
example, 10) or there is no entry for the Low Band Switch, the analyzer will
control the attenuators as if they are 26.5 GHz attenuators, not the 50 GHz
attenuators that are actually installed. If this occurs, skip this procedure and
troubleshoot the Low Band Switch.
Press AMPTD, Attenuation 0 dB on the analyzer.
Attenuation LEDs DS14 through DS20 should be off.
When the input attenuation is changed from 0 to 8 dB in 2 dB steps, LEDs
DS14 through DS16 should be illuminated as per
6, and 8 dB attenuator settings are only available on analyzers with Option
FSA, Fine Step Attenuator.
If this is incorrect, the most probable cause is the A15 Front End Control
Assembly.
Keysight N9010A EXA Service Guide
Table 6-6 Input Attenuator A LED's (Opt 543, 544, 550)
Attenuator Setting
(dB)
0
a
2
a
4
a
6
a
8
a. These settings available only if analyzer has Option FSA, Fine
Step Attenuator.
Table
DS14 DS15
OFF OFF
OFF ON
ON ON
OFF OFF
OFF ON
6-6. Note that the 2, 4,
DS16
OFF
OFF
OFF
ON
ON
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