Faulty Motherboard or power supply (or both)

  • Thread starter Thread starter kenmor
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kenmor

I built my machine about 2 and a half years ago based around
Gigabyte GA-8S655FX-L motherboard (socket 478) with a P4 2.4 GH
processor. I am not an experienced techie and I have n
sophisticated test equipment

It went wrong a few weeks ago and having considered severa
possibilities. I am fairly sure that it is the motherboard, processo
or possibly power supply at fault, but I would appreciate any comment
especially on the power supply (see below)

After switching on there is power as the fans operate, at least on
LED is lit and there is power to the USB optical mouse (the lase
shows red). This means I am getting basic power but the 12V powe
could still be faulty I suppose.

There are no POST messages or beeps, and there is no attempt to boo
from an inserted floppy. The lack of beeps or boot reading of flopp
would seem to rule out the video card

I have replaced the CMOS battery with a new one (leaving the batter
removed for some time so that I get the default BIOS)

Removing memory modules makes no difference. (Still no POST o
beep)

I have tried making sure all connectors and cards are firmly seated

This seems to be probably a motherboard problem (do you agree?) but
wanted to check the power supply and so I got another one (both ar
well up to spec). This starts out the same but the power goes of
after a few seconds i.e. the fans start and then stop. Is this likel
to be the power supply reacting somehow to the motherboard bein
faulty or is my second power supply likely to be faulty even if th
first one isn’t? I want to get to the bottom of this because I a
not keen on buying a new motherboard if this is not the problem

Any comments would be much appreciate
 
I built my machine about 2 and a half years ago based around a
Gigabyte GA-8S655FX-L motherboard (socket 478) with a P4 2.4 GHz
processor. I am not an experienced techie and I have no
sophisticated test equipment.

It went wrong a few weeks ago and having considered several
possibilities. I am fairly sure that it is the motherboard, processor
or possibly power supply at fault, but I would appreciate any comments
especially on the power supply (see below).

After switching on there is power as the fans operate, at least one
LED is lit and there is power to the USB optical mouse (the laser
shows red). This means I am getting basic power but the 12V power
could still be faulty I suppose.

There are no POST messages or beeps, and there is no attempt to boot
from an inserted floppy. The lack of beeps or boot reading of floppy
would seem to rule out the video card.

I have replaced the CMOS battery with a new one (leaving the battery
removed for some time so that I get the default BIOS).

Removing memory modules makes no difference. (Still no POST or
beep).

I have tried making sure all connectors and cards are firmly seated.

This seems to be probably a motherboard problem (do you agree?) but I
wanted to check the power supply and so I got another one (both are
well up to spec). This starts out the same but the power goes off
after a few seconds i.e. the fans start and then stop. Is this likely
to be the power supply reacting somehow to the motherboard being
faulty or is my second power supply likely to be faulty even if the
first one isn’t? I want to get to the bottom of this because I am
not keen on buying a new motherboard if this is not the problem.
Click to expand...

I'd guess the board, if the second supply is really good and not a
cheap piece of crap.
 
kenmor said:
I built my machine about 2 and a half years ago based around a
Gigabyte GA-8S655FX-L motherboard (socket 478) with a P4 2.4 GHz
processor. I am not an experienced techie and I have no
sophisticated test equipment.

It went wrong a few weeks ago and having considered several
possibilities. I am fairly sure that it is the motherboard, processor
or possibly power supply at fault, but I would appreciate any comments
especially on the power supply (see below).

After switching on there is power as the fans operate, at least one
LED is lit and there is power to the USB optical mouse (the laser
shows red). This means I am getting basic power but the 12V power
could still be faulty I suppose.

There are no POST messages or beeps, and there is no attempt to boot
from an inserted floppy. The lack of beeps or boot reading of floppy
would seem to rule out the video card.

I have replaced the CMOS battery with a new one (leaving the battery
removed for some time so that I get the default BIOS).

Removing memory modules makes no difference. (Still no POST or
beep).

I have tried making sure all connectors and cards are firmly seated.

This seems to be probably a motherboard problem (do you agree?) but I
wanted to check the power supply and so I got another one (both are
well up to spec). This starts out the same but the power goes off
after a few seconds i.e. the fans start and then stop. Is this likely
to be the power supply reacting somehow to the motherboard being
faulty or is my second power supply likely to be faulty even if the
first one isn’t? I want to get to the bottom of this because I am
not keen on buying a new motherboard if this is not the problem.

Any comments would be much appreciated
Click to expand...

Wow. Ummm, there is not enough information in this post to figure out what
is really going on. I suspect you are dealing with multiple bad components.
The fact that your symptom changed (even slightly) when the power supply was
changed tells me that at least ONE of your power supplies is bad. Or, at
least ONE of them is not spec'd properly to run your system. But it's
possible that both power supplies could be bad.

But then the fact that you aren't getting any beeps from the mainboard with
either power supply is a bad sign, also. Whether the CPU can run POST or
not, the mainboard should give at least one beep, every time it is powered
up. If no beep, that seems to indicate a bad mainboard, ASSUMING (and this
is not a valid assumption, necessarily) that at least ONE of the power
supplies you tried is GOOD.

We need to back up a bit, and start with what we know. You had a working
system. At some point, it stopped working. Obviously, there is a problem
with one or more of the ORIGINAL components. As changing the ORIGINAL power
supply changed the symptom, there is a better than 50/50 chance that the
ORIGINAL power supply is bad.

But before you troubleshoot further, you need to verify that your symptom is
the same with a KNOWN GOOD power supply. The easiest way to do this would
be to borrow a KNOWN GOOD power supply from another system, just long enough
to verify that with a GOOD power supply, the system still doesn't work.

When you get that far, re-post the results of what you've tried. But
assuming that the system still doesn't beep or POST with a KNOWN GOOD power
supply, your next suspect should be the mainboard. But I do NOT advise you
to buy a new mainboard until you have tried a known good power supply on the
current mainboard. A brand new power supply isn't necessarily
good". -Dave
 
The first goal is to get the POST (Power On Self Test) boot beep whe
you power up, you will get this even with all the disc drive
disconnected inc. the hard disc itself

You checked the bios battery is a good step, ensure the new is ok an
not flat and that it is inserted corectly

The next thing is the Graphic card, try re-inserting it, thi
sometimes cause problems, if possible try by substition one way o
the other just to get it booting, here we are not interested in th
correct drivers etc cos it 'has' to boot to install em'

This leaves the CPU since you have tried another Power Supply, agai
substition may prove something.... if the CPU fan is stiff or feel
sticky to turn then you could well suspect the CP

Bad or swollen capacitors (caps for short) these should stand out lik
a sore thumb, their tops will be bulged and not flat and no gooe
gunge coming from them from the top or from below can cause almos
any problem

See-:
http://home.earthlink.net/~doniteli/index27.htm for what I mean

On a good mobo with no ram inserted you will get a series of beeps. N
doubt you've checked the FAQ's above

Dav
 
kenmor said:
I built my machine about 2 and a half years ago based around a
Gigabyte GA-8S655FX-L motherboard (socket 478) with a P4 2.4 GHz
processor. I am not an experienced techie and I have no
sophisticated test equipment.

It went wrong a few weeks ago and having considered several
possibilities. I am fairly sure that it is the motherboard, processor
or possibly power supply at fault, but I would appreciate any comments
especially on the power supply (see below).

After switching on there is power as the fans operate, at least one
LED is lit and there is power to the USB optical mouse (the laser
shows red). This means I am getting basic power but the 12V power
could still be faulty I suppose.

There are no POST messages or beeps, and there is no attempt to boot
from an inserted floppy. The lack of beeps or boot reading of floppy
would seem to rule out the video card.

I have replaced the CMOS battery with a new one (leaving the battery
removed for some time so that I get the default BIOS).

Removing memory modules makes no difference. (Still no POST or
beep).

I have tried making sure all connectors and cards are firmly seated.

This seems to be probably a motherboard problem (do you agree?) but I
wanted to check the power supply and so I got another one (both are
well up to spec). This starts out the same but the power goes off
after a few seconds i.e. the fans start and then stop. Is this likely
to be the power supply reacting somehow to the motherboard being
faulty or is my second power supply likely to be faulty even if the
first one isn�t? I want to get to the bottom of this because I am
not keen on buying a new motherboard if this is not the problem.

Any comments would be much appreciated
Click to expand...

As others have suggested, you must establish that SOMETHING is good.
Davy hinted that you can simplify your problem by removing some items.
That is what I would do to find the problem. Disconnect your HDs,
DVD/CDs, floppy disk drives and any other plugin cards or cables not
necessary to see a video output. You could have a component pulling
down the PS and by removing it temporarily establish what component it is.

Once you have something on the monitor you can add one component at a
time to see which one is causing your failure. Also make sure the
processor fan is plugged in properly. Some MBs shut everything down
when no current is detected by the circuit providing the current for the
fan. Make sure your RAM is good also, as although many will sound an
audible error code for no RAM or failing RAM, I am not sure all will.

The suggestion of faulty caps on the MB is also a good one. Simplify
your problem to the lowest possible level, or test some of the critical
items (RAM, PS, CPU) on another MB in order to establish if they are OK.
 
kenmor "contributed" in alt.comp.hardware.pc-homebuilt:
I built my machine about 2 and a half years ago based around a
Gigabyte GA-8S655FX-L motherboard (socket 478) with a P4 2.4 GHz
processor. I am not an experienced techie and I have no
sophisticated test equipment.

It went wrong a few weeks ago and having considered several
possibilities. I am fairly sure that it is the motherboard, processor
or possibly power supply at fault, but I would appreciate any comments
especially on the power supply (see below).

After switching on there is power as the fans operate, at least one
LED is lit and there is power to the USB optical mouse (the laser
shows red). This means I am getting basic power but the 12V power
could still be faulty I suppose.

There are no POST messages or beeps, and there is no attempt to boot
from an inserted floppy. The lack of beeps or boot reading of floppy
would seem to rule out the video card.

I have replaced the CMOS battery with a new one (leaving the battery
removed for some time so that I get the default BIOS).

Removing memory modules makes no difference. (Still no POST or
beep).

I have tried making sure all connectors and cards are firmly seated.

This seems to be probably a motherboard problem (do you agree?) but I
wanted to check the power supply and so I got another one (both are
well up to spec). This starts out the same but the power goes off
after a few seconds i.e. the fans start and then stop. Is this likely
to be the power supply reacting somehow to the motherboard being
faulty or is my second power supply likely to be faulty even if the
first one isn’t? I want to get to the bottom of this because I am
not keen on buying a new motherboard if this is not the problem.

Any comments would be much appreciated
Click to expand...

I'd say you built your system 2 and a half years ago and never took care
to check the CPU fan for dust in those 30 months afterwards. The fan got
stucked and your CPU is now fried.

Now you also know what those strange sounds are that came from your
computer, starting just some weeks ago before your system went dead.
 
I'm a bit of a newb at troubleshooting and what not, but try re-seating
your processor and, when you put the fan back on (assuming you have a
fan and not a heat synch or water cooling) make sure it's bolted
securely to the mobo.
 
Since replacing the PSU did not fix the problem, it does indeed appear that
your motherboard has failed.
 
Since replacing the PSU did not fix the problem, it does indeed appear that
your motherboard has failed.
 
Thanks for the comments and suggestions. Some of the points I hav
tried already but I shall work through them again methodically

Unfortunately I do not have access to another P4 machine that I ca
use to borrow the power supply or try mine. I think my only optio
is to obtain yet another one – I shall try one from a company tha
breaks up working computers for parts (cheap) and if I still get th
same problem I shall go for a new motherboard

If that doesn’t work then, after pulling my hair out, I suppose i
will have to be a new processor
 
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