Dell Precision WorkStation 420 Service Manual page 18

CAUTION: Before you remove the computer cover, see
To remove a Rambus in-line memory module (RIMM), perform the following steps.
CAUTION: To avoid the possibility of electric shock, turn off the computer and any peripherals, disconnect them from their
electrical outlets, and then wait at least 5 seconds before you remove the computer cover.
CAUTION: The RIMMs can get extremely hot during system operation. To avoid dangerous burns, be sure that the RIMMs
have had sufficient time to cool before you touch them.
1. Remove the computer cover.
2. Press the securing clips outward simultaneously until the RIMM disengages and pops out slightly from the socket (see Figure 24).
Figure 24. RIMM Removal
To install replacement memory, perform the following steps.
CAUTION: To avoid the possibility of electric shock, turn off the computer and any peripherals, disconnect them from their
electrical outlets, and then wait at least 5 seconds before you remove the computer cover. Also, before you replace memory,
see the other precautions in
1. Remove the computer cover.
2. If necessary, remove any RIMMs that occupy sockets in which you plan to install the replacement RIMMs.
NOTES: If you are not installing a replacement RIMM at this time, you MUST remove the remaining RIMM in the pair and install a pair
of continuity modules (CRIMM).
When operating with a single pair of RIMMs, they MUST occupy sockets RIMMB-1 and RIMMA-2, with CRIMMs installed in RIMMB-3
and RIMMA-4.
3. Install the RIMMs:
a. Locate the plastic securing clips at each end of the socket (see
b. Press the clips outward until they snap open.
c. Press the RIMM straight into the slot running down the center of the socket until the securing tabs snap into place around the ends
of the RIMM.
Figure 25. RIMM Installation
4. Replace the computer cover, and reconnect your computer and peripherals to their electrical outlets and turn them on.
"Precautionary
1 Securing clips (2)
"Precautionary Measures. "
Measures"
Figure 25).
1 Securing clips (2)
2 Notches (2)