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Troubleshooting the Power System
To verify that a power supply is functioning normally, perform
the following steps:
- Check the LEDs on each power supply faceplate. If an AC
power supply is correctly installed and functioning normally, the AC OK and DC OK LEDs light steadily, and the PS FAIL LED is not lit. If
a DC power supply is correctly installed and functioning normally, the PWR OK, BRKR ON, and INPUT OK LEDs
light green steadily.
For more information about the LEDs, see AC Power Supply LEDs or DC Power Supply LEDs.
- Issue the CLI show chassis environment pem command to check the status of installed power supplies. As shown
in the sample output, the value Online in the rows labeled State indicates that the power supplies in slots 0 and 1 are functioning normally:
user@host> show chassis environment
PEM 0 status: State Online Temperature OK DC output OK PEM 1 status: State Online Temperature OK DC output OK
If a power supply is not functioning normally, perform the following
steps to diagnose and correct the problem:
- If a red alarm condition occurs, issue the show chassis
alarms command to determine the source of the problem.
If the system temperature exceeds the threshold, the JUNOS software
shuts down all power supplies so that no status is displayed.
The JUNOS software also can shut down one of the power supplies
for other reasons. In this case, the remaining power supplies provide
power to the services gateway, and you can still view the system status
through the CLI or display.
- Check that the DC circuit breaker --
or AC switch | is in the on position and is receiving power.
- Verify that the source circuit breaker has the proper
current rating. Each power supply must be connected to a separate
source circuit breaker.
- Verify that the AC power cord or DC power cables from
the power source to the device are not damaged. If the
insulation is cracked or broken, immediately replace the cord or cable.
- Connect the power supply to a different power source with
a new power cord or power cables. If the power supply status LEDs
indicate that the power supply is not functioning normally, the power
supply is the source of the problem. Replace the power supply with
a spare, as described in Replacing Power System Components.
- If you cannot determine the cause of the problem or need
additional assistance, see Juniper Networks Technical Assistance Center.
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