NEC PowerMate Enterprise Manual page 186

4-16 Maintenance and Troubleshooting
5. With the positive (+) side facing up, press the new battery into the socket.
6. Replace the system unit cover as described in Section 3.
Connect external peripherals and power cables.
7.
Run Setup to reconfigure system parameters (see Section 2, "Setup and
8.
Operation").
WARNING: The battery can explode if it is
incorrectly replaced or improperly discarded.
Use only the same battery or an equivalent type
recommended by the manufacturer when
replacing the battery.
Lithium acts as a catalyst when exposed to water
and causes spontaneous combustion on contact.
Discard used batteries according to the
manufacturer's instructions.