Cisco Catalyst 4000 Series Switches

Field Notice: Cosmetic Discoloration of Catalyst 4000 Immersion Silver Printed Circuit Boards (PCBs)

May 5, 2004

Products Affected

This issue potentially affects all Catalyst 4000 linecards that use an Immersion Silver Printed Circuit Board finish.

Problem Description

Some Catalyst 4000 Immersion Silver Printed Circuit Board (PCB) surface finishes which are not covered by solder may become discolored over time. This discoloration is purely cosmetic in nature and has NO impact on product performance or product functionality.


Immersion Silver is one of several surface finishes commonly used on PCBs in both the electronic and automotive industries. Discoloration of Catalyst 4000 Immersion Silver surfaced PCBs commonly occurs for a couple of reasons:

  1. If Immersion Silver surfaced PCB's come into contact with finger oil residue from bare hands.

  2. If Immersion Silver surfaced PCB's are exposed to excessive levels of humidity.

Cisco takes every precaution to ensure that Catalyst 4000 products containing Immersion Silver finish are free from discoloration when they are shipped from our factories.

Problem Symptoms

Dark smudges and areas of discoloration appear on the silver surfaces of a Catalyst 4000 PCB. The edge rails of a PCB are the most common locations for discoloration to occur.


Customers are encouraged not to handle Immersion Silver PCBs by the edge rails. No other workaround is required.

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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