★ Troubleshooting Ideas for Switch Fan Noise

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When a customer powers on a new switch and starts it up with two fan modules installed, they find that one of the fan modules is making a loud noise.

1. Swap the fan module with the loud noise with the one that has normal noise to determine if the issue is caused by the fan module itself.

By replacing and observing, it is found that when either of the two fan modules is inserted into the FAN1 slot, there is a significant increase in noise. Therefore, it can be concluded that the issue is not due to a hardware fault in the fan module itself.

2. Check if the software-defined airflow direction of the switch matches the actual airflow direction of the fan. Use the "display fan" command to check:

  <H3C>display fan 

   Slot 1: 

   Fan 1: 

   State: Normal 

   Airflow Direction: Port-to-power 

   Prefer Airflow Direction: Port-to-power 

   Fan 2: 

   State: Normal 

   Airflow Direction: Port-to-power 

   Prefer Airflow Direction: Port-to-power 

Since the Airflow Direction and Prefer Airflow Direction are both Port-to-power, it can be concluded that there is no abnormal configuration command.

3. Check the temperature of the switch. Use the "display environment" command to check:

[H3C]display environment 

System temperature information (degree centigrade): 

---------------------------------------------------------------------- 

Slot Sensor Temperature Lower Warning Alarm Shutdown 

1     hotspot 1 23           0    57        62      NA

The temperature of the switch is 23℃, which is within the normal operating temperature range. Therefore, it can be concluded that the issue is not due to abnormal environmental conditions or temperature sensors.

4. Check the abnormal noise and normal fan speed. Use the "fancontrol fanstatus" command in diagnostic mode to check:

[H3C]probe // Enter diagnostic mode 

[H3C-probe]fancontrol fanstatus 

Now soft control fanspeed 

Fan 1 speed is 19047

Fan 1 PWM is c8 

Fan 2 speed is 3720 

Fan 2 PWM is 10

From the information, it is confirmed that the speed of Fan 1, which has the loud noise, is 19047, much higher than the normal noise level of Fan 2. Additionally, the Fan 1 PWM is "c8," indicating that the fan is running at full load. 

Based on the above, it can be concluded that the reason for the excessive fan noise is the high speed of Fan 1.

1. Temporarily reduce the fan speed manually to minimize the impact of fan noise on on-site personnel.

[H3C]probe // Enter diagnostic mode 

[H3C-probe]cpld read 1 1a // Read the PWN value of the abnormal fan 1 (1a) in slot 1 

Read Addr 26 OK Value = 0xC8. 

[H3C-probe]cpld read 1 1b // Read the PWN value of the normal fan 2 (1b) in slot 1 

Read Addr 27 OK Value = 0x10. 

[H3C-probe]cpld write 1 1a 10 // Manually adjust the PWN value of the abnormal fan 1 (1a) in slot 1 to the PWN value of the normal fan 2 Write Addr 26 OK Value = 0x10.

[H3C-probe]fancontrol fanstatus // Check the fan speed, Fan 1 and Fan 2 speeds have returned to normal 

Now manual control fanspeed 

Fan 1 speed is 3718 

Fan 1 PWM is 10 

Fan 2 speed is 3720 

Fan 2 PWM is 10 

With this, the issue of excessive fan noise in the S5560-30-EI switch has been temporarily resolved.

2. Collect relevant device information and report it to the 400 engineer. The command collection method is as follows: 

<H3C>system-view 

[H3C] display environment 

[H3C]probe // Enter diagnostic view 

[H3C-probe] fancontrol fanstatus // Collect this command three times, with an interval of about 5 minutes each time 

[H3C-probe] fancontrol paramshow 

[H3C-probe] debug sysm fan 0 get-speed 

[H3C-probe] display drv system 4 

Finally, collect diagnostic information for the faulty device. 

<H3C>display diagnostic-information

Save or display diagnostic information (Y=save, N=display)? [Y/N]:y // Choose Y to save the diagnostic information

Please input the file name(*.diag)[flash:/default.diag]: 

Diagnostic information is outputting to flash:/default.diag. 

Please wait................................................... 

Save successfully.

<H3C>tftp 1.1.1.1 put flash:/default.diag // Export the diagnostic information from the switch to the PC. "1.1.1.1" is the IP address of the PC, and "flash:/default.diag" is the information following "Diagnostic information is outputting to."