Keysight N8973B User Manual

240 Keysight NFA Series Noise Figure Analyzers Service Guide
Front End Control Troubleshooting
A15 Front End Control Assembly Troubleshooting
Input Attenuator A Control Logic Verification (N8976B)
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 MODE/MEAS, Spectrum Analyzer, OK, AMPTD, Attenuation, Mech
Atten, 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 Table 6-5.
If this is incorrect, the most probable cause is the A15 Front End Control
Assembly.
Ignore DS11 in this procedure.
Table 6-5 Input Attenuator A LED’s (N8976B)
Attenuator Setting
(dB)
DS14 DS15 DS16
0OFFOFFOFF
2 OFF ON OFF
4ONONOFF
6OFFOFFON
8 OFF ON ON

Keysight N8973B Specifications

General

Brand	Keysight
Model	N8973B
Category	Measuring Instruments
Language	English