Dell R 420 Manual

1.screws (2)
2.power supply cables to the system board (3)
3.power supply cable to the hard-drive 
backplane
4.standoffs (2)
5.power distribution board
6.fan cable connector
Installing The Power Distribution Board
CAUTION: Many repairs may only be done by a certified service technician. You should only perform 
troubleshooting and simple repairs as authorized in your product documentation, or as directed by the online or 
telephone service and support team. Damage due to servicing that is not authorized...

h)internal dual SD module
i)expansion card holder
NOTE: It is recommended that you remove the power distribution board before removing the system board 
from the chassis.
5.Disconnect all other cables from the system board.
CAUTION: Do not lift the system board assembly by grasping a memory module, processor, or other 
components.
6.Remove the nine screws on the system board and slide the system board toward the front of the system.
7.Slide the system board toward the front of the system.
Figure 60....

3.Hold and align the system board by its edges and align it to the back of the chassis.
4.Lower the system board and align the screw holes to the standoffs on the chassis till firmly seated.
5.Tighten the screws of the system board to secure the system board to the chassis.
6.Replace the following:
a)expansion card holder
b)expansion-card risers
c)expansion cards
d)integrated storage controller card
e)memory modules
f)internal dual SD module
g)PDB shroud
h)cooling shroud
7.Reconnect all cables to the...

104 

4
Troubleshooting Your System
Safety First—For You And Your System
CAUTION: Many repairs may only be done by a certified service technician. You should only perform 
troubleshooting and simple repairs as authorized in your product documentation, or as directed by the online or 
telephone service and support team. Damage due to servicing that is not authorized by Dell is not covered by your 
warranty. Read and follow the safety instructions that came with the product.
Troubleshooting System Startup...

7.Power down all attached USB devices and disconnect them from the system.
8.Restart the system and, if your keyboard is functioning, enter the System Setup. Verify that all USB ports are 
enabled on the 
Integrated Devices screen, in the System Setup options.
If your keyboard is not functioning, you can also use remote access. If the system is not accessible, reset the 
NVRAM_CLR jumper inside your system and restore the BIOS to the default settings.
9.Reconnect and power on each USB device one at a...

Troubleshooting A Wet System
CAUTION: Many repairs may only be done by a certified service technician. You should only perform 
troubleshooting and simple repairs as authorized in your product documentation, or as directed by the online or 
telephone service and support team. Damage due to servicing that is not authorized by Dell is not covered by your 
warranty. Read and follow the safety instructions that came with the product.
1.Turn off the system and attached peripherals, and disconnect the system...

–Hard-drive carriers
–Hard-drive backplane
4.Ensure that all cables are properly connected.
5.Close the system.
6.Run the system board tests in the system diagnostics.
If the tests fail, see Getting Help.
Troubleshooting The System Battery
CAUTION: Many repairs may only be done by a certified service technician. You should only perform 
troubleshooting and simple repairs as authorized in your product documentation, or as directed by the online or 
telephone service and support team. Damage due to...

•System cover, cooling shroud, EMI filler panel, memory-module blank, or back-filler bracket is removed.
•Ambient temperature is too high.
•External airflow is obstructed.
•A cooling fan is removed or has failed.
•The expansion card installation guidelines have not been followed.
Troubleshooting Cooling Fans
CAUTION: Many repairs may only be done by a certified service technician. You should only perform 
troubleshooting and simple repairs as authorized in your product documentation, or as directed by...

If an error message is displayed on the screen, this may indicate a problem with the installed DIMM type(s), 
incorrect DIMM installation, or defective DIMM(s). Follow the on-screen instructions to resolve the problem. For 
more information, see General Memory Module Installation Guidelines.
14.Close the system.
15.As the system boots, observe any error message that is displayed and the diagnostic indicators on the front of the 
system.
16.If the memory problem is still indicated, repeat step 12 through...