Jim's Self-Help

CPU Installation Procedures

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Static Electricity

Always use anti-static bags or foam to store an unused CPU.

The risk of static discharge is a major concern when handling or installing a CPU. Static electricity can build up within your body and discharge to the CPU without you realizing it has happened. Combinations of cold weather, carpets, and leather soled shoes can be especially devastating. The use of anti-static devices such as wrist straps (for $7.00) or anti-static mats is strongly encouraged. If these are not available, be sure to touch the metal back of your computer or some other grounded metal object in order to discharge yourself before handling the CPU or other internal computer parts.

Motherboard Settings

Not all motherboards support all CPU types

Before attempting installation of a CPU, check your motherboard manual to be sure it supports the brand, voltage, and speed of the CPU you wish to install. Unless you are doing an exact CPU replacement, it will probably be necessary to change certain jumpers on the motherboard to accommodate the new CPU. If you don't have the motherboard manual (surely you haven't lost it), you might luck out and find the jumper settings printed on the board itself. Otherwise, it is virtually impossible to know how to set the board. We can't help you unless we sold you the board. No two boards are alike.

JUMPERS:
Small black jumpers are used to connect upright gold pins on the motherboard, their purpose being to complete various electrical circuits which provide a variety of options that a single motherboard can support. Pins are presented at various locations on the motherboard in groups usually ranging from two to five pins. Pins within each group are numbered beginning with "1" for each group. If pins for some groups are not numbered, number 1 is always on the same side of all groups. The pin groups are usually labeled as J1, J2, JP1, JP2, etc., both on the board and in the manual. The manual indicates which pins should be "jumped" (connected or closed), or "open" (not jumped), in order to accommodate various options.

VOLTAGE:
You can damage your CPU if you install it in a motherboard that does not support the proper voltage, or is not jumped to supply the proper voltage. Most of today's high-speed CPU's are 3.3 volt, and tomorrow's CPU's will be even lesser voltage. Many older 486 boards support only 5 volt CPU's, which means an Intel DX2-66 is as good as it's gonna get. Some older AMD DX2-66 CPU's are 5 volt, newer ones are 3.3 volt. Some CPU's have their voltage printed on them.

BRAND:
Most boards require different jumper settings for different brands of CPU's, and perhaps even different jumper settings for different models of the same brand and speed of CPU. Some CPU's have a model number printed on them.

SPEED:
Depending on the CPU RATING (MHz), the motherboard must be jumped for both the proper CPU CLOCK and SYSTEM CLOCK:

CPU Removal

Always disconnect electricity before removing your computer case.

Before removing your CPU, notice its orientation. One corner should be different from the other three, and may have a small dot on it, or the corner itself may be beveled at a 45% angle. After removing the CPU, note the same corner of the socket on the motherboard is also similarly marked, with one corner different from the other three in some manner. The new CPU must be inserted so the odd corners of the CPU and socket match.

ZIF SOCKETS:
If your motherboard is equipped with a ZIF (Zero Insertion Force) socket, there will be a lever located on one side of the CPU socket. Gently press this lever down and slightly away from the CPU in order to release the lever latch. Once the lever is free, raise it to an upright position, which will release socket tension on the CPU. The CPU can then be removed by simply grasping the sides and pulling straight up.

CAUTION - the pins on the underside of the CPU are easily bent and frustratingly difficult to straighten.

OTHER SOCKETS:
The removal of your old CPU from a non ZIF motherboard can be accomplished using a CPU removal tool or a flat-head screwdriver.

CAUTION - The CPU can be broken by applying excessive force when attempting to remove it. Carefully loosen one side of the CPU by inserting the screwdriver between the CPU and socket and gently prying until it gives slightly. Then loosen the other sides in the same manner. Continue to rotate sides, forcing each side up slightly more on each rotation until the CPU is free.

CAUTION - forcing one side up significantly above the level of the other sides will bend the pins on the underside of the CPU.

CPU Installation

Inspect the CPU to ensure that all underside pins are straight.

ZIF SOCKETS:
Orient the CPU so the odd corner matches the odd corner of the socket. With the lever in an upright position, gently place the CPU on the socket, being sure that all pins line up with the socket holes. When pins are aligned, the CPU should seat itself in the socket. Apply very light pressure to ensure the CPU is evenly seated. Push the lever down and ensure it latches firmly.

OTHER SOCKETS:
Orient the CPU so the odd corner matches the odd corner of the socket. Gently place the CPU on the socket, being sure that all pins line up with the socket holes.
CAUTION - If pins are not aligned exactly with the holes, forcing the CPU will bend pins. Once certain the pins are aligned, pressure may be necessary to force the CPU into the socket  .Use moderate pressure on alternate corners of the CPU until it appears to be properly seated. Once seated, apply firm pressure to all four corners.

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