If the router displays the system bootstrap version and hangs or falls into a booting loop, repeating the same information, the memory may not be well-seated. To address this issue, perform these steps:
Re-seat by removing and then re-inserting the DRAM SIMM memory. A faulty or poorly-seated module can cause the router to enter a boot loop.
Physically remove all network modules and power on the router.
If the router goes back into a loop, replace the router chassis.
If the router does not go back into a loop, add a network module, and boot the router. If the router loads without errors, repeat until all of the modules have been tested.
If one of the modules causes the router to go back into a loop, try the module in another slot. This narrows the issue to either the card or the slot.
Replace the faulty hardware.
Note: If the router does not experience the continuous loop after following the troubleshooting steps, then the problem may be caused by a mis-seated network module. Monitor the router for 24 hours to make sure that the router continues to function without experiencing the issue again.
When hardware replacement is indicated after troubleshooting:
If you have a hardware support contract directly with Cisco for this part, use the Service Order Submit Tool to request a replacement part directly.
For warranty service, contact the Cisco Technical Assistance Center (TAC) directly at 1-800-553-2447, or online by using the TAC Service Request Tool.
If your product is not covered by contract or warranty, contact your Cisco partner or reseller to request a replacement part for the hardware component that is causing the issue.