HP A4500A Hardware Manual - rp24xx, Customer Viewable - Page 127

CPU Cleaning for System Board Replacement

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Adding CPUs and Socket Cleaning CPU Cleaning for System Board Replacement This section provides information for those situations where CPUs are removed and then replaced onto the same system board or onto a new system board. 1. Carefully vacuum the area surrounding the CPU to be removed and replaced. 2. Remove the CPU assembly. 3. Install the system board socket dust cover (A3639-40024) (item 6) into the empty system board socket. 4. Place the CPU assembly on its side in a clean, ESD safe area. 5. Remove the CPU assembly socket by pressing the four (two on each side) tabs holding the socket to the CPU heat sink base. The CPU chip may come off with the socket or stay attached to the heat sink. (Usually the CPU chip stays in the socket.) 6. Remove the thermostrate pad form the heat sink. It is not necessary to clean the waxy residue left behind on the heat sink and CPU chip. 7. Inspect the system board socket side of the CPU chip for any thermostrate residue. If residue is observed, clean that area with the IPA wipe. CAUTION Do no attempt to clean the new CPU chip socket buttons. 8. Place the CPU chip into the new socket. Match the cut corner of the chip with the angled corner of the socket, and be sure to have the buttons on the chip facing down. The chip should snap into the socket with light downward pressure. 9. Place the O-ring around the outside of the socket's four posts and roll it down against the corner stops. 10. Hold the heat sink assembly upside down (with the bottom up). 11. Place the new thermostrate on the copper base of the heat sink assembly, with the bevelled side down. 12. Lower the CPU chip and socket assembly onto the upside down heat sink. It only snaps in one way. NOTE Be sure to leave the dust cover on the CPU chip until you are ready to re-install the CPU into the system board. 13. Remove the system board socket dust cover installed in step 3 and inspect the old socket for missing or damaged buttons. A hand-held magnifying glass is helpful. Tilt the socket at an angle. Missing buttons will show up as an irregularity in the pattern of contacts. Refer to the photograph below for an example of a socket with a missing button. If missing buttons are observed, take special care in the next step. Chapter 135

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Chapter
Adding CPUs and Socket Cleaning
135
CPU Cleaning for System Board Replacement
This section provides information for those situations where CPUs are removed and then replaced onto the
same system board or onto a new system board.
1. Carefully vacuum the area surrounding the CPU to be removed and replaced.
2. Remove the CPU assembly.
3. Install the system board socket dust cover (A3639-40024) (item 6) into the empty system board socket.
4. Place the CPU assembly on its side in a clean, ESD safe area.
5. Remove the CPU assembly socket by pressing the four (two on each side) tabs holding the socket to the
CPU heat sink base. The CPU chip may come off with the socket or stay attached to the heat sink.
(Usually the CPU chip stays in the socket.)
6. Remove the thermostrate pad form the heat sink. It is not necessary to clean the waxy residue left behind
on the heat sink and CPU chip.
7. Inspect the system board socket side of the CPU chip for any thermostrate residue. If residue is observed,
clean that area with the IPA wipe.
CAUTION
Do no attempt to clean the new CPU chip socket buttons.
8. Place the CPU chip into the new socket. Match the cut corner of the chip with the angled corner of the
socket, and be sure to have the buttons on the chip facing down. The chip should snap into the socket with
light downward pressure.
9. Place the O-ring around the outside of the socket’s four posts and roll it down against the corner stops.
10. Hold the heat sink assembly upside down (with the bottom up).
11. Place the new thermostrate on the copper base of the heat sink assembly, with the bevelled side down.
12. Lower the CPU chip and socket assembly onto the upside down heat sink. It only snaps in one way.
NOTE
Be sure to leave the dust cover on the CPU chip until you are ready to re-install the CPU
into the system board.
13. Remove the system board socket dust cover installed in step 3 and inspect the old socket for missing or
damaged buttons. A hand-held magnifying glass is helpful. Tilt the socket at an angle. Missing buttons
will show up as an irregularity in the pattern of contacts. Refer to the photograph below for an example of
a socket with a missing button. If missing buttons are observed, take special care in the next step.