Juniper MX240 - Removing an MX240 DC Normal-Capacity Power Supply

Removing an MX240 DC Normal-Capacity Power Supply
Before you remove a power supply, be aware of the following:
NOTE: The minimum numberofpower supplies mustbepresentinthe router
at all times.
WARNING: Before performing DC power procedures, ensure that power is
removed from the DC circuit. To ensure that all power is off, locate the circuit
breaker on the panel board that services the DC circuit, switch the circuit
breaker to the off position, and tape the switch handle of the circuit breaker
in the off position.
CAUTION: To maintain proper cooling and prevent thermal shutdown of the
operating 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 Figure 153 on page 340):
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. Attach an ESD grounding strap to your bare wrist and connect the strap to one of the
ESD points 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.
339Copyright © 2017, Juniper Networks, Inc.
Chapter 26: Replacing Power System Components