Fan(S) Are Not Operating - Agilent Technologies N9039A Service Manual

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
LED Does Not Illuminate"
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 7, "Assembly Replacement Procedures," on page 161
3. Are all three fans not spinning?
If yes:
Proceed to step 4.
If not:
Proceed to step 6.
4. Remove the MP7 Top Brace. Refer to
Procedures," on page 161
5. Referring to Figure 2-4, verify that the Fan Supply Failure LED on the A7
Midplane board is off.
Is the Fan LED off?
If yes:
Measure the voltage level at Test Point 522 on the A7 Midplane board.
Is the Test Point 522 voltage between +7 and +15 VDC?
If yes:
Proceed to step
If not:
Replace the A6 Power Supply assembly.
Chapter 2
Potential Problems During Boot Process
section before proceeding.
Chapter 7, "Assembly Replacement
in this manual.
6.
Troubleshooting
"Green Power On
in this manual.
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