Replacing an M40e DC Power Supply
On a DC-powered router, the
router has two load-sharing, redundant DC power supplies. Each power
supply is hot-removable and hot-insertable, as described in M40e Field-Replaceable Units (FRUs).
When one power supply fails or is powered down, the other power supply
automatically assumes the entire electrical load for the router.
Removing an M40e DC Power Supply
The DC power supplies are located at the bottom rear of
the chassis, as shown in M40e Chassis Description. Each DC power supply weighs approximately
13 lb (5.9 kg).
 | 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. |
To remove a DC power supply (see Figure 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. For more information about ESD, see Preventing Electrostatic Discharge Damage to an M Series, MX Series, or T Series Router.
- Press the power switch for the power supply (located on the
circuit breaker box) to the OFF (O) position.
 | Note:
If you are power cycling the power supply rather than
shutting it off for a time, wait at least 60 seconds after turning
it off before turning it back on. If you need to power it off again,
wait for at least 60 seconds after powering it on. |
- Shut off the power flowing to the power supply
from the external power source, so that the voltage across the leads
of the power cables is 0 V. Ensure that there is no chance that
the cable leads might become active during the procedure.
- Loosen the thumbscrew at each corner
of the power supply faceplate, using a Phillips screwdriver if necessary.
- Grasp the handle or handles on the power supply
faceplate and pull firmly to slide the unit about halfway out of the
chassis.
- Place one hand under the power supply to support
it, then slide it completely out of the chassis.
 | Warning:
Do not touch the power connectors on the rear of the
power supply (see Figure 2). They can contain dangerous voltages. |
Figure 1: Removing a DC Power
Supply
Figure 2: Rear of DC Power Supply
Showing Midplane Connectors
Installing an M40e DC Power Supply
To install a DC power supply (see Figure 3):
- Verify that there is no power flowing to the power supply from
the external power source, so that the voltage across the leads of
the power cables is 0 V. Ensure that there is no chance that
the cable leads might become active during the procedure.
- Verify that the power switch for the power supply
(located on the circuit breaker box) is in the OFF (O) position.
- Attach an electrostatic discharge (ESD) grounding strap
to your bare wrist, and connect the strap to one of the ESD points
on the chassis. For more information about ESD, see Preventing Electrostatic Discharge Damage to an M Series, MX Series, or T Series Router.
- Place one hand under the power supply and grasp a handle on
the faceplate with the other hand. Slide the power supply into the
chassis until it contacts the midplane.
- Starting with the bottom screws, tighten (but do
not overtighten) the thumbscrew at each corner of the power supply
faceplate.
- Press the switch on the
corresponding circuit breaker to the ON ( | ) position.
Verify that on the power supply faceplate the green LED labeled CB ON lights steadily, the blue LED labeled OUTPUT OK blinks momentarily, then lights steadily, and the yellow LED labeled CB OFF does not light.
 | Note:
After powering off a power supply, wait at least 60 seconds
before turning it back on. 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, see Disconnecting AC Power from the M40e Router or Disconnecting DC Power from the M40e Router. After a power supply is powered on, it can take up to 60 seconds
for status indicators—such as LEDs on the power supply, show chassis commands, and messages on the craft interface
LCD—to indicate that the power supply is functioning normally.
Ignore error indicators that appear during the first 60 seconds. |
Figure 3: Installing a DC Power
Supply
Published: 2010-10-28