Dell PowerVault 725N (Rackmount NAS Appliance) - Manual (Page 43)

12. Enter the System Setup utility. If the time and date are still incorrect, replace the system board. See " Removing the System Board/Backplane Board
Assembly ."
System Board and Backplane Board
The system board and backplane board provide IDE interface signal routing between the system board and the four IDE hard-drive bays. In addition, the
backplane provides power distribution from the power supply to the system board and to internal peripherals.
The system board and backplane board are removed from the chassis as a single assembly, and then are separated for replacement of either board.
Removing the System Board/Backplane Board Assembly
To remove the system board/backplane board assembly, perform the following steps:
1. Turn off the system and attached peripherals, and disconnect the system from the electrical outlet.
2. Remove the system cover. See " Removing the System Cover ."
3. If you are replacing the system board, remove the system battery. See " Replacing the Battery ."
4. If you are replacing the system board, remove the processors. See " Removing the Processor ."
5. If you are replacing the system board, remove the shroud.
6. If you are replacing the system board, remove the memory modules. See " Removing Memory Modules ."
7. Disconnect the control panel cable from the backplane board. See " Removing the Control Panel ."
8. Disconnect all hard drives from the backplane board:.
a. Push the release lever to the right. See Figure 4 -15 .
b. Open the latch and use it to pull the drive carrier out approximately 2.5 cm (one inch).
c. Repeat this step for each installed drive.
9. Rotate the backplane release latches up. See Figure 4 -21 .
10. Remove the power supply. See " Removing the Power Supply ."
11. Remove the cooling shroud.
12. Remove the blower and fan assemblies. See " Fan Assemblies ."
13. Loosen the thumbscrew securing the system board to the chassis floor.
14. Slide the system board/backplane assembly toward the front of the system and lift the assembly up and out of the chassis. See Figure 4 -21 .
Figure 4-21. System Board/Backplane Board Assembly Removal
CAUTION: See your System Information Guide for complete information about safety precautions, working inside the computer, and protecting
against electrostatic discharge.
NOTICE: When you turn off the system, press the power button for less than 2 seconds. If you press the power button for longer than 3 seconds, the
system will automatically rebuild the RAID arrays the next time the system is turned on. This could impact system performance for several hours.