Cisco 6900 Series Multiplexers

Field Notice: C6920 Power Pack Dual Fuse Issue

September 3, 2002

Products Affected


Top Assembly

Part Number


C6920 RateMux Power Supply



C6920 RateMux Power Supply



Problem Description

All Ratemux power supplies (800-07201-01/-02) currently have two fuses when they are specified to have only one fuse. This is a safety hazard to the technician handling the Ratemux. If the fuse on the neutral line is blown, while the fuse on the hot line is not, the technician servicing the chassis can be shocked.


The power supply used on all RateMux C6920 products currently in the field has two fuses in the mains line: one on the Hot and one on the Neutral. If the fuse on the neutral blows the Hot line of the mains will still be live. This situation may lead to a false sense of safety if the technician that is working on the power supply or chassis assumes that the mains are disconnected from the supply.

Problem Symptoms

The mains Hot lead connected to the power supply remains live, causing the potential for electric shock.



There is no direct solution to the problem. There are no user serviceable parts in the module and care should be taken if working at the component level with the power supply.


The power supply will have the 47-14840-01 warning sticker applied to the top-left hand corner of the power supply front face without covering any existing text on the front face. These warning labels are available and will be proactively distributed to the customer base.

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:

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