Juniper MX2020 Hardware Manual page 411

CAUTION:
power supply unit, each PDM slot must contain either a PDM or a blank panel. If you
remove a PDM, you must install a replacement PDM or a blank panel shortly after the
removal.
NOTE: After powering off a PDM, wait at least 60 seconds before turning the circuit breaker
back on.
1. Switch off the dedicated customer site circuit breaker for the PDM 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. Verify that the –48V LEDs on the PDM to be removed are not lit.
4. Attach an electrostatic discharge (ESD) grounding strap to your bare wrist, and connect the strap to
one of the ESD points on the chassis.
5. Move the DC circuit breaker on the power input source to the OFF position.
6. Remove the clear plastic covers protecting the terminal studs on the faceplate.
7. Remove the nut and washers from each of the terminal studs. (Use a 7/16-in. [11 mm] nut driver or
socket wrench.)
8. Remove the cable lugs from the terminal studs.
9. Carefully move the power cables out of the way.
10. Loosen the two captive screws on the locking levers, and pull away from the chassis.
NOTE: For the MX2020 Router, pull down the PDM3/Input1 and PDM1/Input1 locking
levers to release the PDM from the chassis, and pull up the PDM0/Input0 and
PDM2/Input0 locking levers to release the PDM from the chassis.
To maintain proper cooling and prevent thermal shutdown of the operating
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