At 07:20 AM 10/05/1999 , you wrote:
>My computer does not boot. It does not even ask for my password and it stays blank
>(black). There is no 'bip' sound at start. (computer is a Compaq Presario 425) No response at all.
>I hope somebody can help me... Kumari
Okay... there is no quick answer to this one. I will cut and paste from my
regular weekly column "Troubleshooting Basics", (this appears on our web
site), concerning this issue. This is found in the Volume #1 at:
http://nospin.com/pc/ts001a.html
Computer will not post (start)
We are going to deal with this issue first. It is the
toughest issue for a diagnostician. The easiest way to
solve this issue is with a diagnostics card like those
available from Ultra-X. You simply insert the card in a
computer slot, (either a PCI slot or an ISA slot), turn on
the power and the card will give you a read out of codes
displaying the problem. These cards cost many hundreds
of dollars and a tool for a computer professional, so we
will assume you are not going to buy one. *wink*
You should first remove all the cards, (sound card,
network card, modem and so forth), from the
motherboard. After each of these steps always try to turn
on the computer. If it comes on, you have found your
problem. Remember that solving most problems with a
computer requires good common sense and a little
deductive reasoning. Now remove the ribbon cables from
the motherboard, cables running to drives, ports or other
devices. This does not include the power connection
wires or case LED light wires.
The first thing to check is that you have power running to
the computer, is the wall outlet dead? The next thing to
look for is the fan in the power supply coming on when
you turn on the computer? If you are using an AT form
factor power supply, the fan should at least come on. An
ATX will probably not even turn on the fan if there is an
issue. Now check to see if the power converter switch in
the back of the case, from the power supply is set to your
local power type supplied. In the USA, Canada and many
other areas, that is 110volts. In Europe and a few
countries elsewhere it is 220volts.
The power cables running to the motherboard from the
power supply should be checked to see if they are
properly seated. If it is an AT form factor, be sure that
the two connectors have the black wires next to each
other. Reversing these will cause a problem. In the case
of the AT form factor power supply, disconnect the power
wires from the motherboard and try turning on the power.
The power supply fan should come on, if not, you may
have a bad power switch. In the case of a ATX form
factor, confirm that the power wire is connected properly
to the motherboard to the proper pins, you will need your
motherboard manual to verify the pins this wire connects
with from the switch on the front of the case. Finally,
check that the switch on the ATX power supply, on the
back of the case, is in the 'on' position.
Now, check the Ram memory modules. Remove them
and reseat them. They might have become loosened from
the motherboard. You should also check that the video
card is well seated into the slot on the motherboard. You
can remove the card and reinstall it. If you have not
found the problem, then we move on to the more difficult
measures.
We should now remove the CMOS settings, one or more
of them may be wrong and causing the issue. There are
two ways to deal with this. The simplest is to find the
jumper pins on the motherboard that discharge the power
to the BIOS. You should have your motherboard manual
on hand to find them. If you do not have the manual,
typically you can download one from the motherboard
manufacturer's web site. The computer's power cable
must be unplugged and then you move the jumper to the
discharge position. This only takes about ten seconds,
then you can move the jumper back. The second method
is to remove the battery from the motherboard. This is
straight forward, find the battery on the motherboard,
carefully remove it, wait a couple of minutes and then
replace it.
The next item to check is the CPU. First, if your
motherboard has jumpers to set the clock multiplier and
FSB, check these settings in your manual against the
jumpers on the motherboard. Now, carefully remove the
CPU and examine if for browned areas or obvious signs
of heat damage, then return it to the socket.
Okay. We have checked all the easiest of items. The next
step will require some more creative diagnostics. At this
point, we must confirm that the memory, CPU and video
card are working. To do this, you will need another
computer.You need to switch out each of these items to
the other computer to confirm that it works. Try the video
card and ram memory first. When you switch out the
CPU, you will need to adjust the jumpers on the second
computer's motherboard to match the settings required for
your CPU. If as a matter of course, the second computer
will not boot with one of your components, you probably
have found your problem part. Try using the good part
from the second computer in the first computer to see if it
will run with this component.
Finally, if you have followed all the above measures, you
have verified the CPU, the video card and ram will work
in another computer, you can safely believe that the
motherboard is the problem. You will need to remove
the motherboard and replace it.
Bob Wright
The NOSPIN Group, Inc
http://nospin.com - http://nospin.org
Visit our website regularly for FAQs,
articles, how-to's, tech tips and much more
http://nospin.com - http://nospin.org
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