Huawei OSN 8800

Cations for the Cable of the OptiX OSN 8800 Fan Assembly Is Incorrectly Connected

Summary: Under certain circumstances, a batch of fan assemblies of the Huawei Optical transmission OptiX OSN 8800 T32 or T64 intelligent optical transport platform have a speed regulating problem in high temperature.

Huawei OSN 8800

[Problem Description]
When the version of the fan board is changed according to the requirement, the layout and cabling engineer modifies the slot of the fan board in the fan assembly from fan 1, fan 2, fan 3 to fan 2, fan 3, fan 1 (left-to-right). When regulating the speed of the Huawei OptiX OSN 8800 partition, if the high temperature alarm occurs in the third partition, the full speed command will be dispatched to the J7 terminal. However, the J7 terminal is connected to the fan of the second partition, which results in the board of the third partition is always in high temperature. Modify the speed of the fan in the second partition to a higher rate based on the policy of the adjacent speed modification. That is, the full speed command is dispatched to the J8 terminal. The J8 terminal is connected to the fan of the first partition. Consequently, the board of the third partition is always in the high temperature.

Figure 1 Cable connection

Cable connection

 

Symptom
The NE reports a TEMP_OVER alarm. In the fan assembly, all fans are in full speed except the fan in the third partition.

Figure 2 Partition of a NE

Partition of a NE

Diagnosis Method
Step 1 Check whether a TEMP_OVER alarm is reported. If it is reported, go to the next step. If it is not reported, the fan assembly is not involved in this precaution notice and no further action is required.
Step 2 Query the manufacturer information of the fan assembly, and check whether the fan assembly is included in the delivery list (find the attachment). If it is included, the fan assembly is involved in this precaution notice. Otherwise, it is not involved.

[Root Cause]
In 2009, the version of the fan assembly is changed according to the requirement. The new version has no inheritance to the earlier version because the slot ID of the fan is changed. The manufacturer assembles the device according to the old figure for the assembly. As a result, the speed regulating of the fan assembly fails to be performed.

[Impact and Risk]
The NE reports a TEMP_OVER alarm, which has no impact on the device operation.

[Measures and Solutions]
Temporarily restoration
Manually run the full speed command to the fan assembly for maximum heat dissipation.
Solution
Change the cable order of the fan assembly according to the R&D operation guide. After that, the fan assembly can be used as a spare part.
Install the R4C04SPH870 hot patch that will be published in January 2014).

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