NEC Express5800 series User Manual page 211

Removal
To remove the CPU, provide the preparation of the removal following steps 1 to 7 in the installation
procedure and perform steps 8 to 15 in the reverse order. To remove the heat sink, slide it a little on
the level and remove it.
IMPORTANT:
Remove the CPU only if it is defected. After replacement, select
[Main] → [Processor Settings] → [Processor Retest] and set
[Processor Retest] to [Yes] to restart the CPU for clearing the error
information (see Chapter 4).
After operation, the cool sheet at the bottom of the heat sink may
adhere to the CPU. To remove the heat sink, first turn it left and
right to take it apart from the CPU. If you remove the heat sink with
the cool sheet adhering to the CPU, the CPU and/or the socket may
be damaged.
Put a dust cover and CPU dummy plate on Processor #2 if it is
equipped with no CPU.
The operation of the CPU blade cannot be secured if the CPU is
installed only on the Processor #2 socket.
To reinstall a CPU having been removed, the cool sheet should be
replaced with a new one. Contact your service representative.
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