Microprocessor Cooling Fan - Dell Precision WorkStation 420 Service Manual

Press the processor firmly into its connector until it is fully seated. You must use up to 25 lb of force to fully seat the processor in its connector.
5. Install the two thumbscrews.
6. Replace the airflow shroud.
7. Rotate the power supply back into position, making sure that the securing tab snaps into place.
8. Replace the computer cover, and reconnect your computer and peripherals to their power sources and turn them on.
NOTE: After you remove and replace the cover, the chassis intrusion detector will cause the following message to be
displayed at the next system start-up:
ALERT! Cover was previously removed.
9. Enter System Setup, and confirm that the top line in the System Data area correctly identifies the installed processor(s).
10. While in System Setup, reset the chassis intrusion detector by changing Chassis Intrusion to Enabled or Enabled-Silent.
NOTE: If a setup password has been assigned by someone else, contact your network administrator for information on resetting
the chassis intrusion detector.
11. Run the Dell Diagnostics to verify that the new microprocessor is operating correctly.

Microprocessor Cooling Fan

Figure 34. Microprocessor Cooling Fan Removal
To remove a microprocessor cooling fan, perform the following steps.
CAUTION: Before you remove the computer cover, see
1. Remove the computer cover according to the instructions in
2. Rotate the power supply.
3. Remove the airflow shroud by squeezing in on the two pairs of tabs on the shroud and lift it away.
4. Remove the fan power cable from its connector (see
5. Gently pull the plastic locking tab, and push down on the fan to disengage the four latching tabs holding the fan to the back of the chassis.
6. Pull the fan forward (toward the microprocessor slots) to remove it.
1 Fan power cable
2 Fan
3 Plastic locking tab
4 Latching tabs (4)
"Precautionary Measures."
"Computer Cover."
Figure 28 for the location of the system FAN connector).