Fault Description

After a terminal connecting to the device, it cannot display anything or displays garbled characters.

Possible Cause

• The power module of the device is faulty or the device is not powered on.

• The serial interface connecting to the device is incorrectly configured.

• The cable between the terminal and device is faulty or not firmly connected to the serial interface.

Troubleshooting Roadmap

• Check the power indicator on the device's front panel to ensure that the power module is working properly.

• Ensure that the serial interface is correctly configured.

• Install the cable firmly or replace the cable.

Troubleshooting Procedure

1. Check indicators on the device. If the LED indicator is on, the power module is working properly; if not, the device is not powered on. In this case, see Power Supply Fault for details.

2. Check whether the correct combo interface is selected and whether the physical attributes of the PC are consistent with those of the serial interface. The default parameters are as follows:

   • Baud rate: 9600

   • Data bit: 8

   • Stop bit: 1

   • Parity check: None

   • Flow control: None

3. Ensure that the cable is firmly connected to the serial interface. You can replace it with a new cable to verify whether the cable is faulty.

Fault Description

The device restarts unexpectedly or repeatedly.

Possible Cause

• The hardware is faulty or the software has a bug.

• Other errors occur on the device.

Troubleshooting Procedure

1. Check the causes of a device reset.

   Run the display reset-reason command to check the causes of a device reset.

   • If "Reset for power off" is displayed, the device restarts due to a power-off.
   • If "Reset for unknown reason" is displayed, the device restarts due to an unknown error.
   • If "Reset for update version success" is displayed, the device restarts due to a successful upgrade.
   • If "Reset for update version failed" is displayed, the device restarts due to an upgrade failure.
   • If "Reset for kernel panic" is displayed, the device restarts due to a kernel error.
   • If "Reset for mfpi detect fwd abnormal" is displayed, the device restarts due to a forwarding kernel error.
   • If "Reset for memory use out" is displayed, the device restarts due to insufficient memory.
   • If "Reset for exception" is displayed, the device restarts due to a VOS error.

2. If the fault is not caused by the preceding reasons, a hardware fault occurs or the software has bugs. Contact the technical support personnel.

   Perform the following operations to collect related information and provide the information to the technical support personnel.

   NOTICE:

   Do not power off the device before information is collected.

   1. Collect information according to Information Collection.

   2. Run the following commands to collect related information.

      V200R005C10 and earlier versions:

      <Huawei> display reset-reason
      <Huawei> system-view
      [Huawei] diagnose
      [Huawei-diagnose] display inspect black-box record 8 0 0 0
      [Huawei-diagnose] display inspect black-box record 10 0 0 0
      [Huawei-diagnose] display inspect black-box record 12 0 0 0
      [Huawei-diagnose] display inspect black-box record 13 0 0 0
      [Huawei-diagnose] set kernel-monitor irq
      [Huawei-diagnose] display kernel-monitor irq level 1
      [Huawei-diagnose] display kernel-monitor irq level 2
      [Huawei-diagnose] display kernel-monitor irq level 3
      [Huawei-diagnose] display lastwords all
      

      V200R006C10 and later versions:

      <Huawei> display reset-reason
      <Huawei> system-view
      [Huawei] diagnose
      [Huawei-diagnose] display inspect black-box record assert all
      [Huawei-diagnose] display inspect black-box record deadloop all
      [Huawei-diagnose] display inspect black-box record error all
      [Huawei-diagnose] display inspect black-box record exception all
      [Huawei-diagnose] set kernel-monitor irq
      [Huawei-diagnose] display kernel-monitor irq record-range 1
      [Huawei-diagnose] display kernel-monitor irq record-range 2
      [Huawei-diagnose] display kernel-monitor irq record-range 3
      [Huawei-diagnose] display lastwords all