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Cisco 2900 Series and 3900 Series Hardware Installation Guide
OL-18712-03
Chapter 5      Installing and Upgrading Internal Modules and FRUs
  Replacing Power Supplies and Redundant Power Supplies
Figure 5-30 Cisco 2921 and 2951 Power Supply Components
.
Replacing the Power Supply on the Cisco 3900 Series Routers
Step 1
Read the “Safety Warnings” section on page 5-2 section and disconnect the power supply before you 
perform any module replacement.
1 Fan tray and bezel assembly 2 Power supply
3 Power supply fastening screws (2) 4 (Optional) RPS adapter
5 RPS or secondary power supply fastening 
screws (2)
250908 
1 
4 
2 
5 
5 
3 
SYS 
ACT 
SYS 
PWR1 
AUX 
PWR1 
SYS 
PWR2 
AUX 
PWR2 
Cisco
 2900 Series