Keysight N8976B

160 Keysight NFA Series Noise Figure Analyzers Service Guide
RF Section Troubleshooting (N8973B, 74B, 75B Analyzers)
Troubleshooting
8. Front End Assembly Control Logic Verification
Since the RF Front End Troubleshooting board is connected, now is a good
time to test out the remaining control circuits from the A15 Front End Control
Assembly.
Table 4-9 Front End Control Logic
Test Point Description Instrument Settings Voltage
(VDC)
Tolerance
(VDC)
S2A Sets switch for Low Band/preamp path CF 50 MHz preamp on +9.67 ±0.5
S2B Sets switch for Low Band/preamp path CF 50 MHz preamp on +9.83 ±0.5
S3A Sets E-atten to 5 dB preamps off E-atten = 5 dB +9.67 ±0.5
S3B Sets E-atten to 5 dB preamps off E-atten = 5 dB +9.83 ±0.5
S4A Sets E-atten to 10 dB preamps off E-atten = 10 dB +9.67 ±0.5
S4B Sets E-atten to 10 dB preamps off E-atten = 10 dB +9.83 ±0.5
S5A Sets E-atten to 2 dB preamps off E-atten = 2 dB +9.67 ±0.5
S5B Sets E-atten to 2 dB preamps off E-atten = 2 dB +9.83 ±0.5
S6A Sets E-atten to 1 dB preamps off E-atten = 1 dB +9.67 ±0.5
S6B Sets E-atten to 1 dB preamps off E-atten = 1 dB +9.83 ±0.5
S7A Sets E-atten to 2 dB preamps off E-atten = 2 dB +9.67 ±0.5
S7B Sets E-atten to 2 dB preamps off E-atten = 2 dB +9.83 ±0.5
S8A Sets E-atten to 20 dB preamps off E-atten = 20 dB +9.67 ±0.5
S8B Sets E-atten to 20 dB preamps off E-atten = 20 dB +9.83 ±0.5
S9A Controls in & out to low band preamps off E-atten = off +9.83 ±0.5
S9B Controls in & out to low band preamps off E-atten = off +9.67 ±0.5
S11A Sets path for 1st or 2nd L.O. CF 1 GHz +9.67 ±0.5
S11B Sets path for 1st or 2nd L.O. CF 1 GHz +9.83 ±0.5
S12A Sets path for L.O. normal or
x2 for band 4
CF 1 GHz +9.83 ±0.5
S12B Sets path for L.O. normal or
x2 for band 4
CF 1 GHz +9.67 ±0.5
S13A Sets path for L.O. to either of the high band
mixers and L.O. output
CF 5 GHz
CF 20 GHz
−9.67
+9.67
±0.5
S13B Sets path for L.O. to either of the high band
mixers and L.O. output
CF 5 GHz
CF 20 GHz
+9.83
−9.83
±0.5
S14A Sets path to either band 1 & 2 mixer or band
3 & 4 mixer
CF 5 GHz
CF 20 GHz
−9.83
+9.83
±0.5