Keysight E4990A Troubleshooting Manual page 26

Impedance Analyzer
Step 2.
Check system fan inside.
If the system fan, located on the left side of the chassis inside the
E4990A, does not run, the problem seems to be in the A51 DSP
board or the flat cable between the A51 DSP board and A60 CPU
module. In this case, remove the E4990A outer cover and
determine if the fan runs or not.
If a beep and power shutdown occurs immediately after the power
is turned on, there is a possibility that the fan would not run. The
power shutdown occurs the moment the system fan stops by any
anomaly. In this case, check the fan.
If the power shutdown occurs without a beep, the problem seems
to be with the A51 DSP board or the A60 CPU module.
Step 3. Check LED of "Num Lock" key.
Press the Num Lock key on the keyboard. If the LED on the
keyboard does not light as shown in
be in the A60 CPU module.
Figure 6 LED of the Num Lock key
Check the following before replacing the A60 CPU module.
• Connections to the A60 CPU Module are normal
• There are no disconnections or loose connections
Troubleshooting
Figure 6, a problem seems to
1
25