Service manual

5 131
Power Supply Troubleshooting
TROUBLSHOOT THE FAN AND THE A50 DC-DC CONVERTER
5. Power Supply Troubleshooting
TROUBLSHOOT THE FAN AND THE A50 DC-DC
CONVERTER
Perform the following procedure to troubleshoot the fan and the A50 DC-DC Converter.
1. Troubleshoot the Fan
1. Turn the analyzer power off.
2. Disassemble the rear panel.
3. Remove the fan power cable from the Motherboard A20J22.
4. Connect a DC power supply, a 10 kΩ resistance, and a oscilloscope to the fan power
cable using appropriate wire as shown in
Figure 5-9.
Figure 5-9 Fan Troubleshooting Setup
5. Turn the DC power supply on. Adjust the output voltage to +24V.
6. Check the fan is rotating. Check the FAN LOCK signal is as shown in Figure 5-9
• If the fan is not rotating or the FAN LOCK signal is unexpected, replace the fan.
• If these are good, the fan is verified.
7. Reconnect the fan power cable to the Motherboard A20J22.