Copyright 2010 by Morris Rosenthal -All Rights Reserved
Illustrated How to Replace a CPU - AMD Athlon
Despite the high clock speeds and high heat dissipation of modern CPU,
out-and-out CPU failure is a fairly rare ocurrence. Replacing a CPU isn't
particularly challenging if you've done it before, but it can be a little
intimidating for the first timer. To avoid endless repetition opening the
case, I'm replacing the CPU in the same system I used to demonstrate replacing
a power supply and a sound card. It's a 1000 MHz (1 GHz) AMD Athlon in Socket
A, a technology that is still be used for some lower cost PCs. Note that
upgrading a laptop CPU is rarely possible or cost
The first step to replace a CPU is to remove the heatsink. Well, actually,
the first step is to buy a new CPU, and you can
choose from a whole selection at Amazon. All modern CPU's
require an active heatsink, a chunk of finned heat-conductive metal with
a cooling an mounted on top. The leading cause of CPU failure is probably
fan failure, since the CPU can overheat and sustain damage if there's not
enough cooling air flowing over the fins. The only rule of thumb for removing
heatsinks is to study the latching mechanism then use your thumb to release
A standard Socket A heatsink is latched on both sides, but as soon as you
release the main spring force by doing the easy side, the other side will
fall off as you lift the heatsink away from the CPU. You can see the dried
out (not so good) thermal compound on our old Athlon as we lift away the
heatsink. You can just see the same dried out crud on the bottom of the heatsink
at this angle.
All modern CPUs since the inception of Socket 7 back in the early 90's have
used ZIF (Zero Insertion Force) sockets, where the CPU legs are locked in
place by moving a locking lever. To remove the Athlon CPU, we first have
to release the locking lever and lift it up to the vertical position. The
Athlon CPU is then lifted straight out of the socket (below). Also below,
to the right, we show the keying on two corners of the socket and the CPU
that prevents you from installing it improperly.
The new Athlon CPU we are installing here isn't a new CPU at all, it's a
"pull", a CPU that's been removed from a system. When you shop for a replacement
CPU to install on an older motherboard, you'll see that the prices are super
low and most are identified as "pulls. The Athlon is installed in the socket
and locked into place with the locking lever, which is pulled a little away
from the side of the socket to get past the locking nub.
Now comes the critical step. All modern CPUs require some sort of thermal
material be added to the die to improve the thermal interface with the heatsink.
The purpose of a thermal compound, like this Arctic Silver Ceramique, is
to fill in the microscopic voids in both the CPU die and the metal bottom
of the heatsink. You down't want to drown the CPU in thermal compound, just
use enough (many manufacturers define the amount as a large grain of rice
or a small pea) so when the heatsink presses down on it it will spread it
over the die.
That's it, time to reinstall the heatsink by first latching the far side
of the retaining spring over the center nub on the opposite side of the socket.
You can see it latched on here between the capacitors, which makes this the
"poor access" side and the reason we install the CPU heatsink retainer on
this side first.
Next we do the hard side, which we've mad a lot easier by pulling the power
supply first:-) With the active heatsink in place, the final step is reconnecting
the power to the heatsink fan (below) to the CPU fan point on the motherboard.
It's critical you connect it to the proper point which the BIOS manages for
low power and sleep modes.