The customer reported that they are using an MX480 router, and following a midplane replacement, the new chassis began shutting down intermittently—typically within 15 to 20 minutes of being powered on.

The device was consistently shutting down every 15 to 20 minutes, with failure reports indicating issues across multiple FRU components.

The customer reported an issue with an MX480 router. After performing a midplane replacement, the new chassis began shutting down intermittently—typically within 15 to 20 minutes of being powered on. Additionally, several FRU components, including the Control Board (CB) and Power Entry Modules (PEMs), were reported to be entering a fault state.

Troubleshooting Steps Taken:

    Physical Inspection:
    Verified the physical condition of the device, including the status of all PEMs. All PEMs were found to be functioning         normally.

   Software Verification:
   Checked for any software-related issues. No core dumps were generated during the shutdown or reboot cycles.

  Power Supply Check:
 Confirmed that all FRU components were receiving power.

Upon further investigation, it was discovered that the fan tray was either missing. As a result, the device was not receiving adequate cooling. This led to a significant rise in ambient temperature, triggering the thermal protection policy. Consequently, multiple FRUs were falsely reported as failed due to overheating, and the device shut down to prevent thermal damage