HP Compaq dx7400, Service & Reference Manual, Page: 90 / 199

5. Go to step 7.
6. If using a new heatsink, remove the protective covering from the bottom of the heatsink and place
it in position atop the processor.
7. Secure the heatsink to the system board and system board tray with the 4 captive screws and
attach the heatsink control cable to the system board.
CAUTION: Heatsink retaining screws should be tightened in diagonally opposite pairs (as in an
X) to evenly seat the heatsink on the processor. This is especially important as the pins on the
socket are very fragile and any damage to them may require replacing the system board.
NOTE: After installing a new processor onto the system board, always update the system ROM
to ensure that the latest version of the BIOS is being used on the computer. The latest system ROM
BIOS can be found on the Web at:
http:///\h18000.www1.hp.com/support/files .
System Board
1. Prepare the computer for disassembly ( Preparation for Disassembly on page 56 ).
2. Remove the access panel ( Access Panel on page 57 ).
3. Remove the front bezel and lay the computer down on its side to make it easier to work on ( Front
Bezel on page 58 ).
4. Disconnect the power, and data cables from the back of all installed drives.
5. Remove the system fan ( System Fan on page 77 ).
6. Disconnect all cables from the system board.
7. Remove the heatsink from the system board ( Heatsink on page 78 ).
8. Remove the eight screws that secure the system board to the chassis (1).
80 Chapter 7 Removal and Replacement Procedures Microtower (MT) Chassis