• Supported Platforms
• T640 Routers

• Related Topics
• T640 Power System Description
• Maintaining the T640 Power Supplies
• T640 Preventing Electrostatic Discharge Damage.
• T640 DC Power Supply Electrical Specifications
• Site Electrical Wiring Guidelines for M Series and T Series Routers

Powering On a T640 Replacement Three-Input 240-A DC Power Supply

To power on a three-input 240-A DC power supply:

1. Attach an electrostatic discharge (ESD) grounding strap to your bare wrist, and connect the strap to one of the ESD points on the chassis.
2. Switch on the customer site circuit breakers to provide voltage to the DC power source cables.
3. Verify that the INPUT PRESENT LEDs on the power supply faceplate are lit steadily, indicating that the inputs are receiving power.
4. Switch the circuit breakers on the power supply to the ON position (|).

   Note: After a power supply is powered on, it can take up to 60 seconds for status indicators—such as the LEDs on the power supply, the command output displays , and messages on the LED display on the craft interface—to indicate that the power supply is functioning normally. Ignore error indicators that appear during the first 60 seconds.

5. Verify that the CB ON LEDs on the power supply faceplate are lit steadily. The CB ON LEDs blink momentarily, then light steadily to indicate that the circuit breakers are on.
6. Verify that the DC OK LED on the power supply faceplate is lit steadily, indicating that the power supply is correctly installed and is functioning properly.

Note: After powering on a power supply, wait at least 60 seconds before turning it off. If the system is completely powered off when you power on the power supply, the Routing Engine boots as the power supply completes its startup sequence. If the Routing Engine finishes booting and you need to power off the system again, first issue the CLI request system halt command. After powering off a power supply, wait at least 60 seconds before turning it back on.