Cisco Catalyst 3750-E Series Switches

Revised July 1, 2008
April 23, 2007

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.

Revision History

Products Affected

Problem Description

Although there has not been a reported safety incident, Cisco is aware of a potential safety issue that can be caused by a welded nut breaking free inside the switch and Redundant Power Supply (RPS).

Tightening the mounting screws used to secure the power supply or blower module to the switch or the RPS can lead to a welded nut on the interior to the switch or RPS breaking free from the chassis sheet metal. A risk of electric shock may exist if the chassis is not properly grounded and the loose nut comes in contact with the power supply line-in and chassis.

Background

This problem could be initiated by the separation of the weld nuts in the mounting screw assemblies that are used to secure the power supplies to the switches and the RPS. Several improperly welded mounting nuts were found, when their associated power supply or RPS mounting screws were tightened, resulting in their weld nuts breaking free inside the units.

The following series of events can result in a safety issue:

• The affected switches or RPS are connected to the power source.
• The unit does not have a proper connection to earth ground.
• A welded nut breaks free when the power supply mounting screws are tightened.
• The nut enters the power supply assembly and lodges between the AC line-in of the power supply and the chassis, creating a short-circuit. Without a proper ground, the chassis will become electrically energized.
• At this point, any contact with the chassis or the mounting rack, if not properly grounded, could result in an electric shock.

This problem involves only switches that run AC power. In addition, only switches with certain switch system serial numbers and version ID of "VO1" are affected by this issue. For the list of affected switches, please follow the link in the Affected System Serial Numbers section.

Likewise, only RPS with certain serial numbers a version ID of "V01" are affected by this issue. For the list of affected RPS, please follow the link in the Affected System Serial Numbers section.

Problem Symptoms

A loose weld nut condition cannot be detected by visual inspection. A unit with a weld nut that has broken free can be detected when one attempts to tighten a power supply or blower mounting screw. Such a screw will not engage the missing weld nut and it will not be possible to completely tighten the screw. Units in operation may be affected by this problem without showing any signs of malfunction.

Workaround/Solution

Workaround:
The solution is to replace the affected switches and RPS. Use the standard RMA process to order replacement.

Solution:
The solution is to replace the affected switches and RPS.

Until a replacement is secured from Cisco, the user can continue to use an impacted switch if it is already installed and operational and all of the following conditions are met:

1) The switch is already mounted in a customer rack.
2) The mounting screws on the power supply or blower have not been un-tightened or retightened.
3) The unit is properly grounded.

If the switch has not yet been installed, do not continue with installation. Instead, use Standard RMA to get a replacement.
Customers should not try to alter any mounting screws, on any suspect units, whether the unit is currently rack mounted or still in its original shipping container.

Affected System Serial Numbers

The list of affected switches' system serial numbers and RPS' serial numbers can be found by following this link.

How To Identify Hardware Levels

The switch system serial number can be found on:

• The packout box.
• A label on the back of the switch.
• Using the show version command. If the switch is already installed in a network, telnet to the switch, or connect directly to the switch console, then type the show version command and reference the switch System serial number and version ID.

Below is an example of the output of the show version command from an affected switch:

Switch#sh ver
Cisco IOS Software, C3560E Software (C3560E-UNIVERSAL-M), Version 12.2(35)SE2, RELEASE SOFTWARE (fc1)
Copyright (c) 1986-2007 by Cisco Systems, Inc.
Compiled Tue 06-Feb-07 00:24 by antonino
Image text-base: 0x00003000, data-base: 0x0144B97C
ROM: Bootstrap program is C3560E boot loader
BOOTLDR: C3560E Boot Loader (C3560E-HBOOT-M) Version 12.2(35r)SE, RELEASE SOFTWARE (fc1)
Switch uptime is 1 minute
System returned to ROM by power-on
System image file is "flash:c3560e-universal-mz.122-35.SE2/c3560e-universal-mz.122-35.SE2.bin"
License Level: ipservices Type: Permanent
Next reboot license Level: ipservices
cisco WS-C3560E-48PD (PowerPC405) processor (revision A0) with 122880K/8184K bytes of memory.
Processor board ID CAT1107R1KA
Last reset from power-on
1 Virtual Ethernet interface
1 FastEthernet interface
52 Gigabit Ethernet interfaces
2 Ten Gigabit Ethernet interfaces
The password-recovery mechanism is enabled.
512K bytes of flash-simulated non-volatile configuration memory.
Base ethernet MAC Address : 00:1A:E2:BE:74:80
Motherboard assembly number : 73-10320-11
Motherboard serial number : CAT110754Y9
Model revision number : A0
Motherboard revision number : A0
Model number : WS-C3560E-48PD-E
Daughterboard assembly number : 800-28590-01
Daughterboard serial number : CAT104500VR
System serial number : CAT1107R1KA --> System Serial Number is on the affected list
Top Assembly Part Number : 800-27547-02
Top Assembly Revision Number : A0
Version ID : V01 --> Affected Version ID
CLEI Code Number : COM7H10ARA
Hardware Board Revision Number : 0x01

Switch Ports Model SW Version SW Image
------ ----- ----- ---------- ----------
* 1 54 WS-C3560E-48PD 12.2(35)SE2 C3560E-UNIVERSAL-M

Configuration register is 0xF

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:

• Open a service request on Cisco.com
• By email
• By telephone

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