Dell Precision WorkStation 420 Service Manual page 39

To remove an expansion-card guide 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 expansion-card guide and
4. Squeeze the tabs on the end of the fan bracket and slide the fan off of the expansion-card guide
Control Panel
Figure 25. Control Panel Removal
To remove the control panel, perform the following steps:
1. Disconnect the control panel cable from the PANEL connector on the system board (see
2. Remove the mounting screw that secures the control panel to the hard-disk drive cage door.
3. Disconnect the chassis intrusion switch cable connector from the control panel.
4. Disconnect the thermal cable connector from the control panel.
5. Disconnect the speaker cable connector from the control panel.
6. Remove the control panel from the chassis.
Chassis Intrusion Switch
Figure 26. Chassis Intrusion Switch Removal
1 Fan power cable
2 Fan
3 Plastic locking tabs (2)
"Precautionary
"Computer
fan.
1 Control panel
2 Thermal cable connector
3 Control panel cable
4 Screw
5 Speaker cable connector
6 Chassis intrusion switch cable
connector
7 Chassis intrusion switch
8 Hard-disk drive cage door
Measures."
Cover."
(see Figure
Figure 28 for the location of the PANEL connector).
24).