Keysight N8976B

188 Keysight NFA Series Noise Figure Analyzers Service Guide
RF Section Troubleshooting (N8973B, 74B, 75B Analyzers)
Troubleshooting
S14B Sets path to either band 1 & 2 mixer or band
3 & 4 mixer
CF 5 GHz
CF 20 GHz
+9.67
−9.67
±0.5
VCC1 Voltage always on 4.8 ±0.5
VCC2 Voltage always on 4.8 ±0.5
VCC3 Voltage always on 7.85 ±0.5
VCC4 Voltage always on 5.0 ±0.5
VCC5 Voltage always on 5.0 ±0.5
TWAD1 Amplifier bias to A13 RF Front End
Assembly
6.0 ±0.5
TWAD2 Amplifier bias to A13 RF Front End
Assembly
6.0 ±0.5
TWAD3 Amplifier bias to A13 RF Front End
Assembly
6.0 ±0.5
TWAD4 Amplifier bias to A13 RF Front End
Assembly
6.0 ±0.5
TWAD5 Amplifier bias to A13 RF Front End
Assembly
6.0 ±0.5
Table 4-17 Front End Control Logic
Test Point Description Instrument Settings Voltage
(VDC)
Tolerance
(VDC)