Cisco ASR-920-20SZ-M Operating and safety instructions

Replace the Power Supply
Before you begin this task, ensure that you have read and understood the safety warnings in the Safety with
Electricity section of the Safety Warnings handout topic.
The Cisco ASR-920-20SZ-M Router power supplies are hot-swappable. If you have installed redundant power
supplies, you can replace a single power supply without interrupting power to the router.
Note
To avoid erroneous failure messages, allow at least 2 minutes for the system to reinitialize after a power supply
has been removed or replaced.
Caution
You can replace the AC or the DC power supply.
•Remove the DC Power Supply, on page 1
•Remove the AC Power Supply, on page 3
Remove the DC Power Supply
This equipment is suitable for installation in Network Telecommunications Facilities and locations where the
NEC applies. The equipment is suitable for installation as part of the Common Bonding Network (CBN).
Note
The grounding architecture of this product is DC-isolated (DC-I) for DC-powered products. DC-powered
products have a nominal operating DC voltage of 48 VDC. Minimal steady state DC operating voltage is 19.2
VDC.
Caution
Replace the Power Supply
1

Procedure
Step 1 Before servicing the power supply, switch off the circuit breaker in your equipment area. As an additional
precaution, tape the circuit-breaker switch in the Off position.
Step 2 Slip on the ESD-preventive wrist strap that was included in the accessory kit.
Step 3 Switch the power supply circuit-breaker switch to the Off (O) position.
Step 4 Pull the terminal block plug connector out of the terminal block head in the power supply.
Step 5 Loosen the captive screw on the DC power supply. See the figure below.
Figure 1: Remove the DC Power Supply
Do not use the captive installation screw to pull out the power supply.
Caution
Step 6 Grasping the power supply handle with one hand, pull the power supply out from the chassis while supporting
it with the other hand.
Step 7 Replace the DC power supply within 5 minutes.
Install the DC Power Supply
Procedure
Step 1 Ensure that the system (earth) ground connection has been made. For ground connection installation instructions,
see the Installing the Chassis Ground Connection section.
Step 2 If present, remove the blank power supply filler plate from the chassis power supply bay opening by loosening
the captive installation screws.
Replace the Power Supply
2
Replace the Power Supply
Install the DC Power Supply

Step 3 Verify that power to the DC circuit connected to the power supply you are installing is off. To ensure that
power has been removed from the DC circuits, locate the circuit breakers for the DC circuits, switch the circuit
breakers to the OFF position, and tape the circuit-breaker switches in the OFF position.
Step 4 Grasp the power supply metal tab with one hand. Place your other hand underneath the power supply. Slide
the power supply into the power supply bay as shown in the figure below. Make sure that the power supply
is fully seated in the bay.
Figure 2: Install the DC Power Supply
Step 5 Tighten the captive installation screw of the power supply. The recommended maximum torque is 5.5
inch-pounds (.62 newton meters).
If you are installing a redundant DC power supply, repeat these steps for the second power source too.
Remove the AC Power Supply
Procedure
Step 1 Disconnect the power cord from the power source. Do not touch the metal prongs on the power cord when it
is still connected to the power supply.
Step 2 Remove the power cord from the power connection on the power supply. Do not touch the metal prongs
embedded in the power supply.
Step 3 Loosen the captive installation screw as shown in the figure below.
Replace the Power Supply
3
Replace the Power Supply
Remove the AC Power Supply

Figure 3: Remove the AC Power Supply
Do not use the captive installation screw or the power retainer to pull out the power supply.
Caution
Step 4 Grasp the AC power supply metal tab with one hand, and slide it part of the way out of the chassis. Place your
other hand underneath the power supply, and slide it completely out of the chassis.
Step 5 Replace the AC power supply within 5 minutes.
Install the AC Power Supply
Procedure
Step 1 Ensure that the system (earth) ground connection has been made. For ground connection installation instructions,
see the Installing the Chassis Ground Connection section.
Step 2 If necessary, remove the blank power supply filler plate from the chassis power supply bay opening, by
loosening the captive installation screws.
Step 3 Grasp the power supply handle with one hand. Place your other hand underneath the power supply, as shown
in the figure below. Slide the power supply into the power supply bay. Make sure that the power supply is
fully seated in the bay.
Replace the Power Supply
4
Replace the Power Supply
Install the AC Power Supply

Figure 4: Install the AC Power Supply
Step 4 Tighten the captive installation screw of the power supply. The recommended maximum torque is 5.5
inch-pounds (.62 newton meters).
Replace the Power Supply
5
Replace the Power Supply
Install the AC Power Supply

Replace the Power Supply
6
Replace the Power Supply
Install the AC Power Supply