Removals and Replacements (Machine Type 2170/71/74/87/90)
BEFORE REMOVING ANY FRU, POWER-OFF THE COMPUTER, UNPLUG ALL POWER CORDS FROM ELECTRICAL OUTLETS, THEN DISCONNECT
ANY INTERCONNECTING CABLES.
-ATTENTION- The system board, processors, adapter cards, DIMMs, and
upgrade processors can be damaged by electrostatic discharge.
Use an electrostatic discharge 
(ESD) strap to establish personal grounding.
If you don't have an ESD strap, establish personal grounding by touching a ground point with one hand
before touching the static-sensitive FRUs.
The arrows in the removals and replacements procedures show the direction of movement to remove
a field-replaceable unit (FRU), to turn a screw, or the direction to press a tab to release the FRU.
Begin all removals by removing the cover (and rear cover, if applicable).
When other FRUs must be removed prior to removing the failing FRU, they are listed at the top of the page.
Go to the removal procedure for each FRU listed, remove the FRU, and then continue with the removal of the failing FRU.
To replace a FRU, reverse the removal procedure and follow any notes that pertain to replacement.
Before disconnecting any cables, note their location and orientation.
Reinstall any new FRUs with cabling in their original location.
for any BUG on this page found - Thank you.