Juniper MX240 Hardware Manual page 434

To restart a high-capacity AC power supply after a shut down due to an over-temperature situation:
1. Move the power switch on the power supply to the off (o) position.
2. Turn off power to where the AC line goes into the power distribution module (PDM) area.
3. Wait for the power supply LEDs to fade out and for the fans inside the power supply to shutdown.
This can take up to 10 seconds.
4. Turn on power to where the AC line goes into the power distribution module (PDM) area.
5. Move the power switch on the power supply to the on (|) position.
6. Verify that the LEDs on the power supply faceplate are properly lit.
7. Issue the CLI show chassis environment pem command and verify the State is ONLINE and the
Temperature is OK.
To restart a high-capacity DC power supply after a shut down due to an over-temperature situation:
1. Switch off the circuit breaker(s) on the DC distribution panel to remove power to the chassis and
power supplies.
2. Switch on the circuit breaker(s) on the distribution panel to power up the chassis and power supplies.
NOTE: The power switch on the power supplies is not part of the outer or inner DC
circuits and therefore does not need to be switched off when restarting the chassis.
NOTE: If output power is not load-balancing correctly in the same zone on an MX router with
a high-capacity AC or DC power supply module, connect two feeds and change the DIP switch
to 1 to boost the voltage on the power supply module.
CAUTION: Do not attempt to power-on the power supply if the LED is still
lit and the fan is still running. If you do, the router will not reboot.
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