Brand: Cisco
Category: Networking
Document Type: Installation Guide
Language: EN
Installation Guide for 3600 Series
Uploaded: Nov. 21, 2025, 8:27 p.m.
Manual Publish Date: 1996-01-01
This document provides instructions for replacing the AC or DC power supply in a Cisco 3620 or Cisco 3640 router. It includes safety recommendations, an overview of power supplies, required tools, and step-by-step procedures for removing the chassis cover, removing the power supply, installing the new power supply, replacing the cover, and reconnecting cables. Troubleshooting tips and service and support information are also provided.
Troubleshooting and error codes
| Problem | Possible Cause | Solution |
|---|---|---|
| Power LED on the front panel is off | No AC or DC input power | Check AC or DC input, AC or DC source, router circuit breaker, and power supply cable/wiring. |
| Incorrect power supply connection to motherboard | Check the power supply connection to the motherboard. | |
| Power supply failure | If the power LED is still off, the power supply may have failed. | |
| Router shuts down shortly after being powered on | Overheating due to fan failure | Check the fans. If fans are not working, check fan power connections. Ensure chassis vents are clear. |
| Environmental site requirements not met | Check the environmental site requirements in your router installation and configuration guide. |