Replacing PC Parts
Computer Repair with Diagnostic Flowcharts
Starting Your Own Computer Business
The Laptop Repair Workbook
Copyright 2011 by Morris Rosenthal
All Rights Reserved
Replacing a motherboard
Copyright 2011 by Morris Rosenthal -All Rights Reserved
Illustrated How to Replace a Motherboard (Removal)
The first step to replacing a motherboard in a desktop computer is to remove
the old motherboard. That may sound trivial, but it's literally half of the
job, and I'm splitting removal and installation onto two pages so it doesn't
get too big. In order to remove the motherboard, you not only have to disconnect
all connections between the motherboard and components in the case, you should
also remove any cables that are simply in the way. Remember to touch the
metal edge of the case to ground yourself from time to time. Some techs like
to leave the power supply plugged in for a ground, but that's pretty crazy
with ATX technology, since if the switch on the back of the supply goes on,
the power supply will be live. I unplug the power supply and avoid dancing
on the rug to generate static electricity. We start by removing the 1x4 power
connector from the hard drives.
Next we remove the data cable from the hard drives. In a larger case, I might
have left the data cables installed on the drive end, but there's very little
clearance between the motherboard and the drive cages, and you don't want
to start wrestling the old motherboard out because you didn't prepare properly.
It's just like working on a car, if you don't get enough stuff out of the
way to have room to get a wrench in and see what you're doing, you're just
wasting time in the long run. Keep in mind that we're replacing the motherboard,
not just taking the old one out, and you don't want to bash the new motherboard
around as you're installing it.
Now it's time to remove the PCI adapters and the video card. All of the adapters
that mount in motherboard slots are secured to the back rail of the case
with single screw each, though the screws are often missing in systems that
have been worked on. You may as well take all the screws out at the same
time and put them aside in a glass or any other small container to keep them
from getting too lost.
You should always handle adapters by the the edges and by the metal bracket
when removing them from the motherboard. Again, you can't race through this
part like you're just waiting to get to the main course, because you're going
to need to put all these adapters back in after you replace the motherboard,
unless the new motherboard has those features integrated in the I/O core.
You should especially avoid touching the gold contacts on the card edge that
pulls out of the motherboard slots, because the oil from your fingers is
an electrical insulator.
Standard ATX motherboards feature a single 10x2, 20 pin connector for the
power supply. The connection features a sort of a simple latch which is released
from the nub on the motherboard connector by depressing the top of the latch
(just below my thumb). You can also see the nub on the motherboard connector,
on the side near the motherboard edge. It can take a bit of force to pull
the connection out of the motherboard even once it's release, since there
are 20 tight connection, so be prepared to use your off hand to hold the
motherboard down if the edge lifts as you remove the connector.
Now we get to removing the data cables from the old motherboard. If we had
more room in the case, I would have left them attached to the drives on the
other end. If you have trouble remembering where everything goes when you
go to install the new motherboard, I'd recommend the book I write for
McGraw-Hill, "Build Your Own PC," which uses extensive photographic illustrations
to detail the complete assembly of three state-of-the-art PCs. Note that
I'm using both hands to pull out the ribbon cable, holding it as near to
the connector as possible. High quality ribbon cables often include a pull
loop or tab so you can remove them without stressing the cable.
The motherboard is actually mounted in the case with a series of screws through
the motherboard, seven in this case, all of which must be removed. About
the worst thing that can happen when you're replacing a motherboard is that
one of the screws will turn and turn without releasing. Normally, this is
due to the screw having been over-tightened in a brass standoff, which comes
unscrewed from the motherboard pan and remains attached to the screw. If
you think this is happening, proceed to removing the rest of the screws first
so you won't place undo strain on the motherboard by flexing it up. If the
standoff thread in the motherboard pan is stripped, you can take off the
other side of the case and grab it with vise grips from the back.
The final set of connections we have to deal with are the front panel leads
that attach to the motherboard. This includes the LEDs for hard drive activity
and power status, the case speaker, and most importantly, the power switch.
ATX systems use a logic switch to tell the motherboard, which is always receiving
a trickle of power from the ATX power supply, to power full on. These are
all small format connectors that easily pull off, and frankly, the power
switch is the only one you really need to reconnect when you replace the
motherboard, the other's are bells and whistles.
Once all the connections to the motherboard are removed and the screws are
all out, you can lift the motherboard a little and pull it away from the
back of the case, where the connectors of the I/O core protrude through the
shield (left). Once you disengage the I/O core, you can lift the motherboard
right out of the case. I usually hold onto a PCI slot and the CPU heatsink,
there's just no room to get your fingers on the edges of the motherboard
in most cases (below). That pretty much covers the removal phase of replacing
a motherboard, so skip over to how to install a new
motherboard if you're ready..
Don't rush to replace anything until you
troubleshoot the motherboard!