Replacing A T640 Two-Input 160-A Dc Power Supply; Removing A T640 Two-Input 160-A Dc Power Supply - Juniper T640 Hardware Manual

T640 Core Router Hardware Guide

Replacing a T640 Two-Input 160-A DC Power Supply

308
Replacing a Front Air Filter Element on a T640 AC or DC Power Supply on page 373
Replacing a Side Air Filter on a T640 AC Power Supply on page 375
1. Removing a T640 Two-Input 160-A DC Power Supply on page 308
Installing a T640 Two-Input DC Power Supply on page 310
2.

Removing a T640 Two-Input 160-A DC Power Supply

CAUTION: Do not leave a power supply slot empty for more than 30 minutes
while the router is operational. For proper airflow, the power supply must
remain in the chassis, or a blank panel must be used in an empty slot.
The router has either one nonredundant power supply or two redundant, load-sharing
power supplies. Each redundant power supply is hot-insertable and hot-removable.
When a redundant power supply is powered down or removed, the other power supply
automatically assumes the entire electrical load for the router. If you have only one power
supply, you must power off the system before removing the power supply.
To remove a two-input 160-A DC power supply:
Make sure that the voltage across the DC power source cable leads is 0 V and that
1.
there is no chance that the cables might become active during the removal process.
For a nonredundant power supply, power off the system. For redundant power supplies,
2.
verify that the other power supply is functional.
Attach an electrostatic discharge (ESD) grounding strap to your bare wrist, and connect
3.
the strap to one of the ESD points on the chassis.
Switch the circuit breakers on the power supply faceplate to the off position (
4.
NOTE: After powering off a power supply, you must wait at least 60
seconds before turning it back on.
Remove the clear plastic cover protecting the terminal studs on the faceplate.
5.
Using a 7/16-in. (11 mm) nut driver, remove the nuts and washers from the terminal
6.
studs (see Figure 174 on page 309).
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