Keysight E4990A Troubleshooting Manual page 25

1
Troubleshooting
24
Step 1.
Check fan operation and DC monitor LED.
If the rear panel fan (blower) doesn't run, a failure in power supply
is assumed. Remove the E4990A outer cover and check if the
following LEDs light:
• +3.3 V and +5 V DC monitor LEDs on A60 CPU module as shown
in Figure 4.
• LEDs on A51 DSP module as shown in
Figure 4 LEDs on CPU module
Figure 5 LEDs on DSP module
Figure 5.
Impedance Analyzer