Lenovo ThinkSystem DM240N Service Manual page 16

Step 3. Remove the NSM module from the shelf:
a. Loop your index fingers through the finger holes of the latching mechanisms on either side of
the NSM module.
Note: If you are removing the bottom NSM module, and if the bottom rail is obstructing
access to the latching mechanisms, place your index fingers through the finger holes from the
inside (by crossing your arms).
b. With your thumbs, press down and hold the orange tabs on top of the latching mechanisms.
The latching mechanisms raise, clearing the latching pins on the shelf.
c. Gently pull forward until the NSM module is about one third of the way out of the shelf, grasp
the NSM module sides with both hands to support its weight, and then place it on a flat stable
surface. When you begin pulling forward, the latching mechanism arms extend from the NSM
module and lock in their fully extended position.
Step 4. Loosen the NSM module cover thumb screw and open the cover.
The FRU label on the NSM module cover shows the location of the four DIMMs, two on either side
of the heat sink, in the center of the NSM module.
Step 5. Physically identify the faulty DIMM.
When a DIMM is faulty, the system logs a warning message to the system console indicating which
DIMM is faulty. Additionally, the DIMM attention (amber) LED, located on the board next to the
DIMM slot, illuminates.
Note: The LED for the faulty DIMM remains illuminated for 10 minutes after you remove the NSM
module from the shelf.
Step 6. Replace the faulty DIMM:
a. Note the orientation of the DIMM in the slot so that you can insert the replacement DIMM using
the same orientation.
b. Eject the DIMM from its slot by slowly pushing apart the ejector tabs at both ends of the DIMM
slot, and then lift the DIMM out of the slot.
Attention: Carefully hold the DIMM by the corners or edges to avoid pressure on the DIMM
circuit board components.
The ejector tabs remain in the open position.
c. Remove the replacement DIMM from its antistatic shipping bag.
d. Hold the DIMM by the corners, and then insert the DIMM squarely into a slot.
The notch on the bottom of the DIMM, among the pins, should line up with the tab in the slot.
When inserted correctly, the DIMM should go in easily but fit tightly in the slot. If not, reinsert
the DIMM.
e. Push down carefully, but firmly, on the top edge of the DIMM until the ejector tabs snap into
place over the notches at both ends of the DIMM.
Step 7. Close the NSM module cover, and then tighten the thumb screw.
Step 8. Reinsert the NSM module into the shelf:
a. Make sure that the latching mechanism arms are locked in the fully extended position.
b. Using both hands, gently slide the NSM module into the shelf until the weight of the NSM
module is fully supported by the shelf.
c. Push the NSM module into the shelf until it stops (about half an inch from the back of the shelf).
You can place your thumbs on the orange tabs on the front of each finger loop (of the latching
mechanism arms) to push in the NSM module.
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Service Guide for DM240N