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Cisco 6100 Series IP DSL Switches

Field Notice: Field Notice: FN - 10211 - 6100 Series DSLAM - Problem with Fan Unit Mechanical Stability


Revised March 6, 2006
February 2, 2000


NOTICE:

THIS FIELD NOTICE IS PROVIDED ON AN "AS IS" BASIS AND DOES NOT IMPLY ANY KIND OF GUARANTEE OR WARRANTY, INCLUDING THE WARRANTY OF MERCHANTABILITY. YOUR USE OF THE INFORMATION ON THE FIELD NOTICE OR MATERIALS LINKED FROM THE FIELD NOTICE IS AT YOUR OWN RISK. CISCO RESERVES THE RIGHT TO CHANGE OR UPDATE THIS FIELD NOTICE AT ANY TIME.


 

Products Affected



Product TAN TAN Rev BAL BAL Rev Comments HW Rev
6100-FU-01= 800-05437-01 -A0 33-0428-01 -A0 ASY,MECH,6100 FAN MODULE N/A

Problem Description

During the shipment of the fan tray module, the screws that secure the fan inside the fan unit may become loose or fall out.

Background



Cisco engineering has discovered isolated cases that during the shipment of the Cisco 6100 fan tray module, the screws that secure the fan inside the fan unit can become loose. If the fan unit is installed with loosened screws, the normal fan unit vibration can cause the fan mounting screws to disengage. In all cases, the fan and screws remained inside the fan tray. This issue can result in a 10 to 20 percent reduction in airflow to the chassis. The reduced airflow can cause heat-related line card failures on a heavily loaded chassis.  

Problem Symptoms



The fan vibrates loose from its mounting bracket and remains inside the fan unit assembly, resulting in reduced airflow into the chassis. The reduced airflow can cause heat related line card failures on heavily loaded chassis.

Workaround/Solution



There is no workaround for this problem. Cisco has updated the Cisco 6100 Fan Unit (6100-FU-01=) to enhance the assembly stability. The update requires the replacement of the screws used to attach the fan inside the fan unit assembly. This enhancement (6100-FAN-UPGD-1=) was made available to existing fan unit customers at no charge.

Cisco recommends that all affected fan units be updated with the fan upgrade kit (6100-FAN-UPGD-1=). Only one upgrade kit is required per fan tray since one upgrade kit will update three fan units. This replacement program is no longer available.


The table below identifies affected and corrected fan units.

Cisco Ordering Number Cisco Part Number
Affected 6100-FU-01= 800-05437-01 (A0)
Corrected 6100-FU-01= 800-05437-01 (B0)

The Cisco fan unit with part number 800-05437-01 (B0) already has the corrected fix applied and does not need to be upgraded.

All fan units shipped after January 13, 2000 already have the corrective fix applied and do not need to be upgraded.

Caution: In software release 2.4.0, removing a fan unit from a currently operating chassis will generate a fan tray alarm, causing the DMT2 line cards to detrain. Under software release 2.4.1, the DMT2 line cards will not detrain from a fan tray alarm.

For More Information 

If you require further assistance, or if you have any further questions regarding this field notice, please contact the Cisco Systems Technical Assistance Center (TAC) at (800) 553-24HR, (408) 526-7209, or send e-mail to tac@cisco.com