Field Notice: FN74261 - Some Cisco NCS560 Systems May Fail When Assembly and Installation Procedures are not Followed Properly During Deployment - Replace on Failure

Some Cisco NCS560 Routers may fail if the Cisco-provided installation guide for assembling the ground lug in the chassis is not followed. The routers may be subjected to physical damage and can stall normal operations if Cisco-provided screws for ground lug, ratcheting torque screwdriver, and recommended torque settings (up to 20 in-lbs) are not followed during chassis assembly of the ground lug.

When the above mentioned instructions are not explicitly followed, a Cisco NCS560 Router  in powered on and fully functional state subjected to assembly with excessive length screws  ignoring max torque setting, may experience a carbonizing event.

Customers who followed the Cisco NCS560 Router ground lug assembly instructions that were provided as part of the hardware installation guide and assembled the ground lug in chassis, with Cisco-provided mechanical components are not affected by this issue.

Cisco has observed that deviation from the recommended installation procedure for the ground lug in Cisco NCS560 Router chassis by not using Cisco-provided screws may cause damage and affect functionality.

To avoid a hazard when instructions are not followed, Cisco has included cautionary labels on the product to indicate the maximum screw length and other screw attributes. Also to make the product robust, Cisco has enhanced mechanical components such as insulators added onto backplane Printed Circuit Board (PCB) to mitigate system failure when excessive screw length and torque are applied. The screws that are now being shipped include an integrated serrated washer.

Customers who deviated from the Cisco NCS560 Router ground lug assembly instructions during deployment may see the deformation shown in the following image around the screw area on the chassis.

The following deviations in the assembly instructions have been observed:

• Using screws that were not shipped with the ground lug, and that exceeds 8mm
• Using uncontrolled torque when tightening the screws 
• Installing the ground lug when the device is powered on

Additionally, NCS560 systems that have deviated from assembly instructions of ground-lug during deployment, is  powered on and fully functional during the incorrect installation of  excessive length screws applied ignoring max torque setting, there could be a carbonizing event in the chassis that may lead to the device not powering on in the future.

Solution

Cisco strongly recommends following the torque settings and assembly instructions in the  Hardware Installation Guide for Ground Lug Installation and using only the Cisco-provided screws, thereby enabling normal operation for the Cisco NCS560 Routers.

Cisco installation instructions for ground bond attachment include the following: 

• Install ground bond before power is turned on.
• Use a ratcheting torque screwdriver  to install the screws.
• Screw torques up to 20 in-lbs.
• Use Cisco-provided screw for the ground lug.
• Do not install Ground lug connection to the device in powered ON condition

The detailed instructions for ground lug assembly can be found in the Installing the Chassis Ground Connection section of the Cisco NCS 560-4 Router Hardware Installation Guide.

For chassis that have already been assembled incorrectly and currently have the deformation that is shown in the Problem Symptom section of the field notice, RMA replacement through manufacturing new buy of the chassis is recommended.

Cisco can supply the new labels and new screw kit (with the integrated serrated washer) as an orderable PID N560-4-SCREWKIT=. The PID will be available for ordering beginning April 28, 2025. Customer can attach the cautionary label to the back of the chassis and use new screw kit to install the ground lug onto the chassis.

Screws for NCS560 Ground Lug Assembly

This illustration shows the difference between the new screw with the serrated washer and the old screw. 

Type-1 (New screw with integrated serrated washer)  

Type-2 (Old screw without the serrated washer) 

Note: If the customer used the Type-2 screw and followed Cisco Installation guide for Ground lug assembly, there is no action required.

Cautionary Labels in the Chassis 

Cautionary labels have been added to the back of the chassis. The labels specify the length and type of the screw to be used and the assembly precautions while installing the ground lug on the chassis. The illustrations shows the label and the locations where it is placed on the chassis.

Cisco NCS560 Routers for which the ground lug installation procedure is not followed may have to be visually inspected for any deformation in the chassis.