Verifying Sw1 And Sw2 (Option Mpb Only) - Keysight n9020a Service Manual

Front End Control Troubleshooting
A15 Front End Control Assembly Troubleshooting
Table 5-10 Front End Control Logic
Test Point Description
TWAD3 Amplifier bias to A13 RF Front End
Assembly
TWAD4 Amplifier bias to A13 RF Front End
Assembly
TWAD5 Amplifier bias to A13 RF Front End
Assembly
Tolerances should be used as a guideline.
NOTE
If any of the voltages measured are incorrect, the most probable cause is the
A15 Front End Control Assembly. Once the switch control logic has been
verified, turn off the instrument. Disconnect the RF Front End Troubleshooting
board cables, and reconnect the analyzer cables to the A15 Front End Control
Assembly. Turn the instrument on and allow it to complete its full boot up
process to Spectrum Analyzer mode.

Verifying SW1 and SW2 (Option MPB only)

SW1 and SW2 can be verified three different ways:
— "Click" Test
— Oscilloscope
— R.F. Signal Tracing
"Click" Test
This test changes between two different path modes. When this is done a
distinct "click" noise from SW1 and SW2 can be heard. Since both switches
switch at the same time, it is difficult to decipher if one is switching and the
other is not.
Press Mode, Preset on the analyzer. Press FREQ, 5 GHz, SPAN, 1 MHz,
AMPTD, More 1 of 2, uW Path Ctrl. Standard Path is the default. Select uW
Preselector Bypass and you should hear a distinct "click" noise if the control
logic from the A15 Front End Control board is getting to SW1 and SW2.
Instrument
Settings
221
Vol tage Tolerance
(VDC) (VDC)
6.0 ±0.5
6.0 ±0.5
6.0
±0.5