Juniper MX240 Hardware Manual page 385

CAUTION:
power supply unit, each power supply slot must contain either a power supply or a
blank panel. If you remove a power supply, you must install a replacement power
supply or a blank panel shortly after the removal.
NOTE: After powering off a power supply, wait at least 60 seconds before turning it back on.
To remove a DC power supply (see
1. Switch off the dedicated customer site circuit breaker for the power supply being removed. Follow
your site's procedures for ESD.
2. Make sure that the voltage across the DC power source cable leads is 0 V and that there is no chance
that the cables might become active during the removal process.
3. Wrap and fasten one end of the ESD grounding strap around your bare wrist, and connect the other
end of the strap to the ESD point on the chassis.
4. Move the DC circuit breaker on the DC power supply faceplate to the off (O) position.
5. Remove the clear plastic cover protecting the terminal studs on the faceplate.
6. Remove the nut and washer from each of the terminal studs. (Use a 7/16-in. [11 mm] nut driver or
socket wrench.)
7. Remove the cable lugs from the terminal studs.
8. Loosen the captive screws on the bottom edge of the power supply faceplate.
9. Carefully move the power cables out of the way.
10. Pull the power supply straight out of the chassis.
To maintain proper cooling and prevent thermal shutdown of the operating
Figure 135 on page 390):
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