Installing CPUs and Headsinks:

Both the P-II and Celeron CPUs are packaged as SEC's (Single Edge Cartridges), but the Celeron lacks the external cache and locking package of the PII. Both SEC's are designed to accept heatsinks, the P-II (right), a single piece heatsink and fan for which the P-II package provides the locking mechanism, and the Celeron (left), which requires the two piece assembly.

The P-II heatsink is installed on the unlabled side of the package, with four holes to accept the metal tabs that are attached to the heatsink with permanently mounted fan. Once the heatsink is placed on the P-II, hold it in place, turn over the whole assembly, and lock the heatsink in place with the two locking levers.

Shown here is the bare Celeron SEC, from the back, along with the bracket use to lock either CPU type to the motherboard. You can clearly see (click on pic) the double depth arrangement of traces on the card edge used to make all of the connections in a limited space, reminiscent of the EISA bus.

The Celeron SEC comes without mounting hardware for a heatsink and fan, but does have four holes in the circuit board. A spring loaded backing plate with four male hold-downs is mounted on the back of the card, where you can see all the solder points for the CPU legs coming through in a square.

The actual heatsink with permanently attached fan is then pressed over the CPU side of the card, and locked in place by the four hold-downs protruding through the circuit card. You must take some care in this step because it takes a reasonable amount of force to compress the springs enough to lock on.

New motherboards provide a dedicated connector for powering the heatsink fan required by the P-II or Celeron CPUs. Our Intel motherboard provides three different connectors for powering add-on fans. The proper connector for the heatsink is located between the DIMM banks and the P-II Slot 1 connector.

Finally, you can see the P-II mounted on the motherboard, which in turn is mounted on the removable pan. The P-II SEC is locked in place by the bracket, without the top piece required by the Celeron. A top view will be provided in Part IV.

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