Dell Precision WorkStation 420 Service Manual page 46

NOTE: Before disconnecting a peripheral from the system or removing a component from the system board, verify that the standby
power LED on the system board has turned off. For the location of this LED, see
1. Remove the computer cover.
2. Rotate the power supply.
3. Remove the existing microprocessor from its connector.
Squeeze in on the two pairs of tabs on the airflow shroud and lift it away. Press outward on the guide bracket tabs to release them from the
processor/heat sink assembly. Remove the two thumbscrews. Then pull the processor/heat sink assembly out of its connector (see
32). You must use up to 15 lb of force to disengage the processor from the connector.
Figure 32. Microprocessor Removal
Figure 33. Microprocessor Replacement
4. Insert the new microprocessor into the system board connector (see Figure 33).
Figure 28.
1 Airflow shroud
2 Thumbscrews (2)
3 Processor/heat sink assembly
4 Guide bracket
5 Second processor
1 Airflow shroud
2 Thumbscrews (2)
3 Processor/heat sink assembly
4 Guide bracket
5 Second processor
Figure