Field Notice: FN74297 - Some Cisco Network Convergence System 540 Series Routers — N540X-6Z18G-SYS-D and N540X-4Z14G2Q-D — May Fail When Subjected to 4kV Common Mode Surge Voltage - Replace on Failure

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Updated:April 2, 2026
Document ID:FN74297

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High
Impact Rating:
High
First Published:
2026-Apr-02
Last Published:
2026-Apr-02
Revision:
1.0
Cisco Bug IDs:

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


Affected Product Name Description Comments
N540-6Z18G-10TS50= Screw and torque kit for Beagle  
N540-6Z18G-1TS10= Screw and torque kit for Beagle  
N540-6Z18G-20TS2C= Screw and torque kit for Beagle  
N540X-4Z14G2Q-D NCS540 14x1G + 4x1/10G + 2x10/25G Dual-DC iTEMP Conf-Coat  
N540X-6Z18G-SYS-D NCS540 18x1G SFP + 6x1/10G SFP+ Dual DC iTEMP Conformal Coat  




Defect Information


Defect IDHeadline
CSCwq07458PABU: NCS540: N540X-6Z18G-SYS-D and N540X-4Z14G2Q-D: Add insulative sticker around the power connector and add insulator to conceal exposed screw.

Problem Description


A limited number of Cisco Network Convergence System (NCS) 540 Series Routers with Product ID N540X-6Z18G-SYS-D and N540X-4Z14G2Q-D may fail to power on when exposed to a Common Mode Surge Event greater than 4 kV. A common mode surge event occurs when a sudden voltage spike simultaneously affects both the positive and negative lines with respect to ground, often due to external factors such as lightning strikes or electrical switching disturbances.


Background


A manufacturing process deviation has affected a specific batch of Cisco N540X-6Z18G-SYS-D and N540X-4Z14G2Q-D routers, resulting in a missing screw assembly that connects the Common Mode Surge protector to the ground. The issue has been rectified through corrective actions, and all new devices that are now shipping are assembled correctly. The functionality of the routers is not impacted for any voltage less than 4KV Common Mode Surge.


Problem Symptom


The impacted routers might become unresponsive if subjected to Common Mode Surge of 4kV.


Workaround/Solution


Solution

To determine if a serial number is affected, see the Serial Number Validation section of this field notice. Cisco is offering the screws and accessories kit. 

Cisco recommends properly installing the screws so that the routers can withstand 4KV Common Mode Voltage. The screw location is on the front panel of the router, as shown in the picture. Only one screw is required per affected device. Cisco recommends using only the Cisco-provided screwdriver, which is set to deliver a maximum torque of 0.5Nm.

 

The affected router must be powered off during in the screw installation.

The following table provides various  combination  of screws quantity and Torque Screw drivers.  Once the impacted quantity of devices is determined from the Serial Number Validation section of the field notice, the Product ID with appropriate Screw quantity and accessories to be chosen. Please contact TAC to order any of the below  listed PIDs based on quantiy of Screws  needed.Cisco will ensure the required quantity  is delivered to the specified location.

Product ID Screw Quantity Details
N540-6Z18G-1TS10= 10 The kit contains 10 screws and a torque screwdriver.
N540-6Z18G-10TS50= 50 The kit contains 50 screws and 10 torque screwdrivers.
N540-6Z18G-20TS2C= 200 The kit contains 200 screws and 20 torque screwdrivers.

Affected routers that fail to power on after being subjected to 4kV Common Mode Surge Voltage can be returned to Cisco as part of the Return Materials Authorization (RMA) process.


How to Identify Affected Products


To determine if a router is affected, please follow the instructions provided in the Serial Number Validation section of this field notice.


Serial Number Validation


The Cisco Support Assistant (CSA) can help verify whether a device is impacted by the issue that is described in this Field Notice. To check the device, either enter the serial number in the CSA on the right side of this page or click the following URL: Cisco Support Assistant

Revision History


VersionDescriptionSectionDate
1.0Initial Release—2026-APR-02

For More Information

For further assistance or for more information about this field notice, contact the Cisco Technical Assistance Center (TAC) using one of the following methods:

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