Intel Pentium 4 Processor in the 478-Pin Package Thermal Design Guidelines

Intel

Pentium

4 Processor in the 478-Pin Package Thermal Design Guidelines

22 Design Guide

Figure 4. Desired Thermocouple Location

3. After the marks are scribed, clean the desired thermocouple attach location with a mild

solvent and a lint-free wipe or cloth. Alcohol or acetone should suffice. Cleanliness of the part

is critical for a strong epoxy bond after curing.

4. With thermocouple (T/C) in hand, locate the junction and straighten the wire by hand so that

the first 4-6 inches are reasonably straight. Use the fine point tweezers to ensure that the bead

and the two protruding wires are straight and untwisted. Ensure the second layer of

thermocouple insulation, sometimes clear, is not covering the bead.

5. Place a slight downward bend in the protruding wires approximately 1/16 inch from junction

using the tweezers. This aids the user in ensuring the thermocouple junction contacts the heat

spreader surface.

6. Place the thermocouple on the surface of the part so the bead is contacting the IHS at the

desired location. Hold the T/C with one hand and use a pair of tweezers to apply a cut piece of

Kapton*

tape across the wire approximately about ¼ inch back from the bead. Apply pressure

to the tape to ensure a good bond. Apply additional Kapton* tape along the length of the wire

to ensure a good temporary bond to the part. (See following figure). Check for electrical

continuity between the thermocouple and the IHS using a multimeter. If there is no

electrical continuity between the thermocouple and the IHS, repeat Steps 4-6.

Figure 5. Location of Kapton* Tape for Temporary Bond

7. With the thermocouple temporarily held to the part, apply epoxy to the thermocouple bead for

a permanent bond. If applying Omegabond* 101 epoxy, a small piece of paper works well for

mixing. Follow the manufacturer’s instructions for mixing.

8. Use the Exacto* knife or similar to apply the epoxy to the thermocouple bead. Dab glue on

the bead and the exposed wires. Use only the appropriate amount of epoxy to cement the

thermocouple to the IHS. Excess epoxy will prevent the heatsink from mating flush with the