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Troubleshooting On The Bench
There's nothing more frustrating than a freshly built
PC that will not boot. Normally, you're starting with all new
components and you're not sure if any of them work to begin with.
This article deals with a few common techniques computer technicians
use when dealing with this common problem.
Before you begin yanking out cables and
components, just go over your connections one last time.
A common
mistake is the connection from the case power and reset switches to the
motherboard. Carefully review the motherboard's manual to make
sure these connections are right. Not only do the connectors need
to be on the correct pins, they must also be in the correct orientation.
If that is good, make sure the | / O switch on the back of the power
supply is in the "|" position. Then, give the computer a little
shake. Do you hear any screws bouncing around between the
motherboard and the case? This can cause the system to blow or go
to ground. Lastly, make sure the CMOS jumper is on pins 1-2.
If it is on pins 2-3 the motherboard will not boot. This jumper is
located near the watch-like battery on the motherboard.
Still no POST? Now carefully remove
any PCI and AGP cards. Unplug the power supply and IDE cables to
make life easier. You may already be able to get to the screws
that hold the motherboard to the case. Personally, I like to
remove everything except the CPU and heat-sink before pulling the
motherboard.
Once all components are out of the case,
place the motherboard on an antistatic bag (use the bag the motherboard
shipped it, if possible) or a piece of cardboard. Be sure not to
leave the motherboard running on the cardboard unattended because there
is a remote possibility it could cause a fire.
You may need to rest the cardboard and
bag on top of the case depending on the amount of wire you have with the
case wires and the power supply leads. You can short the pins on
the motherboard to boot without actually using the case wires but we are
not going to cover that here.
Now make sure you only have the bare
minimum of components connected to the motherboard. This means
only one stick of memory (if the motherboard allows only one stick), the
CPU and the video card. Nothing else. The only thing we're
trying to do here is get the system to POST. A successful POST should
result in a single, short beep. Make sure the motherboard has a
built in speaker or you will need to connect an external speaker via
pins on the motherboard.
If you still get nothing, begin swapping
out spare parts if you have them at your disposal. Otherwise, you
will need to start returning the components, starting with the
motherboard, then the CPU. Before returning them, look for visible
signs of damage (scorch marks on the CPU, bubbling capacitors on the
motherboard, etc...).
Good luck. The most important
ingredient in troubleshooting a new PC is patience.
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