56 Keysight NFA Series Noise Figure Analyzers Service Guide
Boot Up and Initialization Troubleshooting
Potential Problems During Boot Process
Fan(s) Are Not Operating
Control of the instrument fans comes from the A6 Power Supply assembly. This
signal is routed from the A6 Power Supply through the A7 Midplane board,
where there is a test point and LED to monitor the level, and is then routed to
the A8 Motherboard where it is filtered before being sent to the Fans. When the
Fans do not come on it could be due to any one of these assemblies. This
procedure will help to determine which one is the cause.
This procedure assumes that the green Power On LED on the front panel does
turn on when the instrument is turned on. If it doesn't, refer to the “Green
Power On LED Does Not Illuminate” section before proceeding.
1. The instrument fans will only turn on when the instrument is connected to
an AC source that has a voltage level and frequency of that specified for
the instrument and the front panel On/Off button has been pressed. Before
proceeding verify that these requirements are being met. Refer to the
instrument rear panel for these requirements.
2. Remove the AC power cord and then remove the instrument cover. Refer
to the Chapter 15, “Assembly Replacement Procedures”, on page 389 in
this manual.
3. Are both fans not spinning?
If yes:
Proceed to step 4.
If no:
Proceed to step 6.
4. Remove the MP7 Top Brace. Refer to Chapter 15, “Assembly Replacement
Procedures”, on page 389 in this manual.
5. Refer to Figure 2-5, verify that the Fan LED on the A7 Midplane board is
on. Is the Fan LED on?
If yes:
Measure the voltage level at TP1 on the A7 Midplane board. Is the
TP1 voltage between +7 and +15 VDC
If yes:
Proceed to step 6.
If no:
Replace the A6 Power Supply assembly.
To Next Page
Loading...
Need help?
General
