Emerson Centellis 2000 Shelf Release 3.0 Manual page 79

The shelf is equipped with up to two PEMs. They are installed in the middle of the shelf's front.
Before replacing a PEM, verify that a second PEM is present with both of its green notification
LEDs lit. This second PEM will provide a single power supply path during the replacement
process.
If no second PEM is installed or operational, you have to power down the system before
exchanging the PEM (see section
Damage of Circuits
Electrostatic discharge and incorrect blade installation and removal can damage circuits or
shorten their life.
Before touching the blade or electronic components, make sure that you are working in an
ESD-safe environment.
System Damage
Inserting or extracting the PEM with the PEM breaker in the ON position may damage your
system.
If power is connected to the shelf, make sure the PEM breaker is in the OFF position before
you insert or extract a PEM.
Replacement Procedure
To replace a PEM proceed as follows.
Personal Injury
Hot PEMs may cause injury.
Allow the PEM to cool before servicing.
1. Put on an ESD wrist strap.
2. Connect the strap to the shelf by attaching the front or rear ESD jack/ESD snap.
Centellis 2000 Shelf Release 3.0 Installation and Use (6806800L99F)
Powering Down the System on page
FRU Installation
67).
79