HP DC7800 - Manual (Page 171)

9 Removal and Replacement Procedures
Ultra-Slim Desktop (USDT) Chassis
Adherence to the procedures and precautions described in this chapter is essential for proper service.
After completing all necessary removal and replacement procedures, run the Diagnostics utility to verify
that all components operate properly.
NOTE: Not all features listed in this guide are available on all computers.
Preparation for Disassembly
See Identifying the Chassis, Routine Care, and Disassembly Preparation on page 51 for initial safety
procedures.
1. Remove/disengage any security devices that prohibit opening the computer ( External Security
Devices on page 160 ).
2. Close any open software applications.
3. Exit the operating system.
4. Remove any compact disc from the computer.
5. Turn off the computer and any peripheral devices that are connected to it.
CAUTION: Turn off the computer before disconnecting any cables.
Regardless of the power-on state, voltage is always present on the system board as long as the
system is plugged into an active AC outlet. In some systems the cooling fan is on even when the
computer is in the “Standby,” or “Suspend” modes. The power cord should always be disconnected
before servicing a unit.
6. Disconnect the power cord from the electrical outlet and then from the computer.
7. Disconnect all peripheral device cables from the computer.
NOTE: During disassembly, label each cable as you remove it, noting its position and routing.
Keep all screws with the units removed.
CAUTION: The screws used in the computer are of different thread sizes and lengths; using the
wrong screw in an application may damage the unit.
8. If the PC is mounted in the accessory mounting stand, remove it from the stand.
Preparation for Disassembly 159