Cisco 6000 Series IP DSL Switches

Field Notice: Cisco 6160 DSLAM Blower Assembly May Short Circuit on Initial Power Up

July 27, 2001

Products Affected


Top Assembly

Printed Circuit Assembly


HW Rev.

Part Number


Part Number





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Problem Description

During the initial power up of a properly grounded chassis, the blower assembly in the Cisco 6160 digital subscriber line access multiplexer (DSLAM) may experience a failure resulting from an electrical short.


Poor alignment of the component clamp during the blower tray assembly process may result in an electrical short between the -48V return and the 5V regulator. This electrical short may cause the failure of the voltage regulator, microprocessor, and associated components within the circuit.

Once the chassis has been properly grounded and powered up without failures, the likelihood of this failure occurring during subsequent powerings is minimal.

Problem Symptoms

During the initial power up of a system with the faulty blower assembly, one or more of the following problem symptoms may be exhibited:

  • Smoke

  • Burning smell

  • Red LED or no LED on the blower assembly

  • "Popping" sound(s), as the board components are damaged


If any of the above problem symptoms occur, immediately remove power from the unit and discontinue use of this product. Contact the Cisco Systems Technical Assistance Center (TAC) to request an Return Material Authorization (RMA) of the blower tray, and do not attempt to use this unit until a replacement blower tray has been provided and installed. No attempt should be made to repair these units.

How To Identify Hardware Levels

The part number of affected units is 74-1259-01.

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) by one of the following methods: