Computer quit

My wife's computer quit on her. Shut it down properly one night and it
refused to boot the next morning. No post, NADA.

Motherboard is an ASUS M3N78. Opening it up and I can see a light on
the motherboard, the fans are all working and I believe the hard drives
are spinning, but there is no signal to the montior (or a second monitor
that I tried).

I would like the opinion of the group whether the problem is:

The power supply? The fact that I'm seeing lights and fans suggests it
is not, but maybe some of the voltages are bad.

The on-board graphics? I guess I could try a plug in graphics card.

The Bios? (not likely but possible)

The processor? (AMD Athlon 64 x2 6000+) Not likely but possible.

Memory? Not likely but possible.

Any suggestions? Things I could test to locate just what the problem is?

This is not urgent; I have set her up with another computer and
installed a fresh load of Win XP and restored her data from a backup.

I'm just curious and would like to salvage the components, if it's
reasonable to do so.

Rich

[Default] On Mon, 18 Jan 2016 07:49:21 -0500, in
microsoft.public.windowsxp.general Rich Hare
wrote:

My wife's computer quit on her. Shut it down properly one night and it
refused to boot the next morning. No post, NADA.

Motherboard is an ASUS M3N78. Opening it up and I can see a light on
the motherboard, the fans are all working and I believe the hard drives
are spinning, but there is no signal to the montior (or a second monitor
that I tried).

I would like the opinion of the group whether the problem is:

The power supply? The fact that I'm seeing lights and fans suggests it
is not, but maybe some of the voltages are bad.

Does it play the music when Windows starts?

The on-board graphics? I guess I could try a plug in graphics card.

The Bios? (not likely but possible)

The processor? (AMD Athlon 64 x2 6000+) Not likely but possible.

Memory? Not likely but possible.

Any suggestions? Things I could test to locate just what the problem is?

This is not urgent; I have set her up with another computer and
installed a fresh load of Win XP and restored her data from a backup.

I'm just curious and would like to salvage the components, if it's
reasonable to do so.

Rich

Micky wrote:
[Default] On Mon, 18 Jan 2016 07:49:21 -0500, in
microsoft.public.windowsxp.general Rich Hare
wrote:

My wife's computer quit on her. Shut it down properly one night and it
refused to boot the next morning. No post, NADA.

Motherboard is an ASUS M3N78. Opening it up and I can see a light on
the motherboard, the fans are all working and I believe the hard drives
are spinning, but there is no signal to the montior (or a second monitor
that I tried).

I would like the opinion of the group whether the problem is:

The power supply? The fact that I'm seeing lights and fans suggests it
is not, but maybe some of the voltages are bad.

Does it play the music when Windows starts?

Nope! It doesn't display ANYTHING. There is no display from the BIOS,
as you usually see before Windows starts to load. It just sits there.

At this point I can't recall whether there is a "beep" from the
motherboard which usually happens before the BIOS starts. For that
matter, I can't recall whether I installed a motherboard speaker on that
system.

Rich

Rich(?),

Nope! It doesn't display ANYTHING. There is no display
from the BIOS, as you usually see before Windows starts to
load. It just sits there.

Have you tried to remove all add-on stuff (video, sound, but also memory)
and see (listen actually :-) ) if the motherboard emits any error-beeps ?

If it doesn't you could try to swap out the power supply and check if the
current motherboard can boot with the new one (emitting error-beeps). If
you got the power supply from another, working 'puter than check if the
origional power supply works there.

Regards,
Rudy Wieser


-- Origional message:
Rich Hare schreef in berichtnieuws
...
Micky wrote:
[Default] On Mon, 18 Jan 2016 07:49:21 -0500, in
microsoft.public.windowsxp.general Rich Hare
wrote:

My wife's computer quit on her. Shut it down properly one night and it
refused to boot the next morning. No post, NADA.

Motherboard is an ASUS M3N78. Opening it up and I can see a light on
the motherboard, the fans are all working and I believe the hard drives
are spinning, but there is no signal to the montior (or a second
monitor
that I tried).

I would like the opinion of the group whether the problem is:

The power supply? The fact that I'm seeing lights and fans suggests it
is not, but maybe some of the voltages are bad.

Does it play the music when Windows starts?

Nope! It doesn't display ANYTHING. There is no display from the BIOS,
as you usually see before Windows starts to load. It just sits there.

At this point I can't recall whether there is a "beep" from the
motherboard which usually happens before the BIOS starts. For that
matter, I can't recall whether I installed a motherboard speaker on that
system.

Rich

R.Wieser wrote:
Rich(?),

Nope! It doesn't display ANYTHING. There is no display
from the BIOS, as you usually see before Windows starts to
load. It just sits there.

Have you tried to remove all add-on stuff (video, sound, but also memory)
and see (listen actually :-) ) if the motherboard emits any error-beeps ?

If it doesn't you could try to swap out the power supply and check if the
current motherboard can boot with the new one (emitting error-beeps). If
you got the power supply from another, working 'puter than check if the
origional power supply works there.

Regards,
Rudy Wieser


-- Origional message:
Rich Hare schreef in berichtnieuws
...
Micky wrote:
[Default] On Mon, 18 Jan 2016 07:49:21 -0500, in
microsoft.public.windowsxp.general Rich Hare
wrote:

My wife's computer quit on her. Shut it down properly one night and it
refused to boot the next morning. No post, NADA.

Motherboard is an ASUS M3N78. Opening it up and I can see a light on
the motherboard, the fans are all working and I believe the hard drives
are spinning, but there is no signal to the montior (or a second
monitor
that I tried).

I would like the opinion of the group whether the problem is:

The power supply? The fact that I'm seeing lights and fans suggests it
is not, but maybe some of the voltages are bad.
Does it play the music when Windows starts?
Nope! It doesn't display ANYTHING. There is no display from the BIOS,
as you usually see before Windows starts to load. It just sits there.

At this point I can't recall whether there is a "beep" from the
motherboard which usually happens before the BIOS starts. For that
matter, I can't recall whether I installed a motherboard speaker on that
system.

Rich

The purpose of Rich's test, is to use a working BIOS and initial
computing sequence, to detect obvious faults. You're using the
setup, to have the CPU talk to you, and say "I'm alive".

The motherboard wants to communicate over the SPKR.

If you remove the video card and RAM, the BIOS considers
those to be fatal errors. It will deliver a characteristic
repeating beep pattern. A different pattern is given for
faulty or missing RAM, than for faulty or missing video.

The CPU can run (a little bit) without system RAM present.
It uses register-based code to do that, executing BIOS
code and using registers for temporary storage. So when you
pull all the RAM, the BIOS code talks to the chipset, polls
the SMBUS, finds no SPD chip with DIMM settings in it on
any DIMM slot, and then it wants to beep the speaker.

The speaker is beeped manually. So when you hear the speaker
beeping, the processor is orchestrating that too. The longer
the speaker beeps properly like that, it shows the processor
itself is "stable".

It's when you connect SPKR, and absolutely no beeps are heard
under any circumstances, that you don't know a thing.

Check that the main power connector, the ATX12V 2x2 square
connector, are connected. The machine can't beep without
ATX12V being connected. The CPU needs power to do the
little beeping act. Both motherboard connectors have lock
latches, so the connectors are not supposed to work loose.
It is up to the user, to ensure during installation,
that the latch is engaged on each one.

So the system beeper (SPKR) is your debugging tool.

The only other items that might be of interest, is the
voltage readings using a $20 multimeter. Such a device would
be accurate enough to determine that, say, the 12V (yellow
wires) are above 11V level. Things like hard drives won't
spin up, unless the full voltage is present.

The system also cannot start, or even beep, if Power_OK,
a signal on the main ATX cable, is not in the right state.
This is how the power supply announces "the buffet table
is now open". Without Power_OK, the signal is part of the
reset tree - the computer will remain with reset asserted,
if Power_OK isn't actually indicating things are OK.

Other onboard regulators, can also gate Power_OK. So if
something like VCore had a status pin, and VCore was
overloaded, that could prevent the system from coming
out of RESET.

The system can also be hobbled (no beeps), if the RESET
button is crushed in the ON state. On some computers, the
buttons are indeed that cheap, and they can be crushed like
that. The button ends up "pushed in", and visually looks
abnormal. The front buttons are a "floating" design, and
the body of the switch is isolated from the two wires
used by the switch.

So what would be a good minimum config ?

1) Motherboard, CPU, CPU_cooler, ATX12V power, main 24 pin power,
no RAM, no video card, no disks, remove other cards, connect SPKR,
connect Power button cable, disconnect RESET button cable,
disconnect front panel LEDs (if you're in the mood). The purpose
of clearing off the PANEL header, is so you can see that just the
minimum necessary electrical connections are in place. If that's
too much work, just pull off the RESET cable.

2) Power up, listen for beeps.

3) Do diagnostics of power supply, if you have the time,
patience and materials. Replace power supply, if you're
made of money, and swapping stuff is your preferred test
method. I keep one spare PSU (in my case, a nice Seasonic),
for swap. Once you become a home repairman, you end up
collecting some stuff for your junk rook, for future
debugging exercises.

HTH,
Paul

Rich Hare wrote:
My wife's computer quit on her. Shut it down properly one night and it
refused to boot the next morning. No post, NADA.

Motherboard is an ASUS M3N78. Opening it up and I can see a light on
the motherboard, the fans are all working and I believe the hard drives
are spinning, but there is no signal to the montior (or a second monitor
that I tried).

I would like the opinion of the group whether the problem is:

The power supply? The fact that I'm seeing lights and fans suggests it
is not, but maybe some of the voltages are bad.

The on-board graphics? I guess I could try a plug in graphics card.

The Bios? (not likely but possible)

The processor? (AMD Athlon 64 x2 6000+) Not likely but possible.

Memory? Not likely but possible.

Any suggestions? Things I could test to locate just what the problem is?

This is not urgent; I have set her up with another computer and
installed a fresh load of Win XP and restored her data from a backup.

I'm just curious and would like to salvage the components, if it's
reasonable to do so.

Rich
Monitor?

--
You either teach people to treat you with dignity and respect, or
you don't. This means you are partly responsible for the mistreatment
that you get at the hands of someone else.

In article , , Rich Hare
says...

My wife's computer quit on her. Shut it down properly one night and it
refused to boot the next morning. No post, NADA.

Motherboard is an ASUS M3N78. Opening it up and I can see a light on
the motherboard, the fans are all working and I believe the hard drives
are spinning, but there is no signal to the montior (or a second monitor
that I tried).

I would like the opinion of the group whether the problem is:

Before you try anything serious, just try de-powering the motherboard -
ie. pull the power cord out, for about 15 seconds.

--
Duncan.

[Default] On Mon, 18 Jan 2016 09:37:09 -0500, in
microsoft.public.windowsxp.general Rich Hare
wrote:

Micky wrote:
[Default] On Mon, 18 Jan 2016 07:49:21 -0500, in
microsoft.public.windowsxp.general Rich Hare
wrote:

My wife's computer quit on her. Shut it down properly one night and it
refused to boot the next morning. No post, NADA.

Motherboard is an ASUS M3N78. Opening it up and I can see a light on
the motherboard, the fans are all working and I believe the hard drives
are spinning, but there is no signal to the montior (or a second monitor
that I tried).

I would like the opinion of the group whether the problem is:

The power supply? The fact that I'm seeing lights and fans suggests it
is not, but maybe some of the voltages are bad.

Does it play the music when Windows starts?

Nope! It doesn't display ANYTHING. There is no display from the BIOS,
as you usually see before Windows starts to load. It just sits there.

At this point I can't recall whether there is a "beep" from the
motherboard which usually happens before the BIOS starts. For that
matter, I can't recall whether I installed a motherboard speaker on that

If you didn't, you can use just about any speaker, most 6" and smaller
are 4 ohms, but even 8 ohm, and you can connect it with wires and
alligator clips if need be. I mean one speaker, not a box with two
of them in it, but even that your mobo might have thepower to drive.

If nothing works, there is software that will, it says allow you to
install your files and your current OS on a computer with different
hardware. AHDS or something, Home something and one other. I can
get the names if you get to the point you want to move to another box.
system.

Rich

At this point I can't recall whether there is a "beep" from the
motherboard which usually happens before the BIOS starts. For that
matter, I can't recall whether I installed a motherboard speaker on that
system.

Rich

The purpose of Rich's test, is to use a working BIOS and initial
computing sequence, to detect obvious faults. You're using the
setup, to have the CPU talk to you, and say "I'm alive".

The motherboard wants to communicate over the SPKR.

If you remove the video card and RAM, the BIOS considers
those to be fatal errors. It will deliver a characteristic
repeating beep pattern. A different pattern is given for
faulty or missing RAM, than for faulty or missing video.

The CPU can run (a little bit) without system RAM present.
It uses register-based code to do that, executing BIOS
code and using registers for temporary storage. So when you
pull all the RAM, the BIOS code talks to the chipset, polls
the SMBUS, finds no SPD chip with DIMM settings in it on
any DIMM slot, and then it wants to beep the speaker.

The speaker is beeped manually. So when you hear the speaker
beeping, the processor is orchestrating that too. The longer
the speaker beeps properly like that, it shows the processor
itself is "stable".

It's when you connect SPKR, and absolutely no beeps are heard
under any circumstances, that you don't know a thing.

Check that the main power connector, the ATX12V 2x2 square
connector, are connected. The machine can't beep without
ATX12V being connected. The CPU needs power to do the
little beeping act. Both motherboard connectors have lock
latches, so the connectors are not supposed to work loose.
It is up to the user, to ensure during installation,
that the latch is engaged on each one.

So the system beeper (SPKR) is your debugging tool.

The only other items that might be of interest, is the
voltage readings using a $20 multimeter. Such a device would
be accurate enough to determine that, say, the 12V (yellow
wires) are above 11V level. Things like hard drives won't
spin up, unless the full voltage is present.

The system also cannot start, or even beep, if Power_OK,
a signal on the main ATX cable, is not in the right state.
This is how the power supply announces "the buffet table
is now open". Without Power_OK, the signal is part of the
reset tree - the computer will remain with reset asserted,
if Power_OK isn't actually indicating things are OK.

Other onboard regulators, can also gate Power_OK. So if
something like VCore had a status pin, and VCore was
overloaded, that could prevent the system from coming
out of RESET.

The system can also be hobbled (no beeps), if the RESET
button is crushed in the ON state. On some computers, the
buttons are indeed that cheap, and they can be crushed like
that. The button ends up "pushed in", and visually looks
abnormal. The front buttons are a "floating" design, and
the body of the switch is isolated from the two wires
used by the switch.

So what would be a good minimum config ?

1) Motherboard, CPU, CPU_cooler, ATX12V power, main 24 pin power,
no RAM, no video card, no disks, remove other cards, connect SPKR,
connect Power button cable, disconnect RESET button cable,
disconnect front panel LEDs (if you're in the mood). The purpose
of clearing off the PANEL header, is so you can see that just the
minimum necessary electrical connections are in place. If that's
too much work, just pull off the RESET cable.

2) Power up, listen for beeps.

3) Do diagnostics of power supply, if you have the time,
patience and materials. Replace power supply, if you're
made of money, and swapping stuff is your preferred test
method. I keep one spare PSU (in my case, a nice Seasonic),
for swap. Once you become a home repairman, you end up
collecting some stuff for your junk rook, for future
debugging exercises.

HTH,
Paul

Paul,
Thank you for an EXCELLENT discussion of what happens at the motherboard
level during boot-up! This is EXACTLY what I need to begin some
experiments to find out just what is wrong, and also just what is still
good.

I've assembled about a dozen computers over the years and learned a lot
about installing OS's (including MSDOS 6.0, Win95, various Linux
versions, etc, and dealt with hard drive quirks and other things, but
this is the first time something was working well for a couple of years
and just died, with not proximate cause, such as a voltage surge.

I've got a couple of brand new power supplies (don't ask why, just went
crazy at a computer store once) and I'm sure I've got a handful of those
dime sized mini speakers that plug into the "speaker" pins on the
motherboard. This will be fun for me to play with and see if I can coax
this beast back to life.

I'll have some free time on Wednesday and I'll report back on what I'm
able to find.

Rich

[Default] On Mon, 18 Jan 2016 11:12:13 -0500, in
microsoft.public.windowsxp.general Paul wrote:

R.Wieser wrote:
Rich(?),

Nope! It doesn't display ANYTHING. There is no display
from the BIOS, as you usually see before Windows starts to
load. It just sits there.

Have you tried to remove all add-on stuff (video, sound, but also memory)
and see (listen actually :-) ) if the motherboard emits any error-beeps ?

If it doesn't you could try to swap out the power supply and check if the
current motherboard can boot with the new one (emitting error-beeps). If
you got the power supply from another, working 'puter than check if the
origional power supply works there.

Regards,
Rudy Wieser


-- Origional message:
Rich Hare schreef in berichtnieuws
...
Micky wrote:
[Default] On Mon, 18 Jan 2016 07:49:21 -0500, in
microsoft.public.windowsxp.general Rich Hare
wrote:

My wife's computer quit on her. Shut it down properly one night and it
refused to boot the next morning. No post, NADA.

Motherboard is an ASUS M3N78. Opening it up and I can see a light on
the motherboard, the fans are all working and I believe the hard drives
are spinning, but there is no signal to the montior (or a second
monitor
that I tried).

I would like the opinion of the group whether the problem is:

The power supply? The fact that I'm seeing lights and fans suggests it
is not, but maybe some of the voltages are bad.
Does it play the music when Windows starts?
Nope! It doesn't display ANYTHING. There is no display from the BIOS,
as you usually see before Windows starts to load. It just sits there.

At this point I can't recall whether there is a "beep" from the
motherboard which usually happens before the BIOS starts. For that
matter, I can't recall whether I installed a motherboard speaker on that
system.

Rich

The purpose of Rich's test, is to use a working BIOS and initial
computing sequence, to detect obvious faults. You're using the
setup, to have the CPU talk to you, and say "I'm alive".

The motherboard wants to communicate over the SPKR.

If you remove the video card and RAM, the BIOS considers
those to be fatal errors. It will deliver a characteristic
repeating beep pattern. A different pattern is given for
faulty or missing RAM, than for faulty or missing video.

The CPU can run (a little bit) without system RAM present.
It uses register-based code to do that, executing BIOS
code and using registers for temporary storage. So when you
pull all the RAM, the BIOS code talks to the chipset, polls
the SMBUS, finds no SPD chip with DIMM settings in it on
any DIMM slot, and then it wants to beep the speaker.

The speaker is beeped manually. So when you hear the speaker
beeping, the processor is orchestrating that too. The longer
the speaker beeps properly like that, it shows the processor
itself is "stable".

It's when you connect SPKR, and absolutely no beeps are heard
under any circumstances, that you don't know a thing.

Check that the main power connector, the ATX12V 2x2 square
connector, are connected. The machine can't beep without
ATX12V being connected. The CPU needs power to do the
little beeping act. Both motherboard connectors have lock
latches, so the connectors are not supposed to work loose.
It is up to the user, to ensure during installation,
that the latch is engaged on each one.

So the system beeper (SPKR) is your debugging tool.

The only other items that might be of interest, is the
voltage readings using a $20 multimeter. Such a device would
be accurate enough to determine that, say, the 12V (yellow
wires) are above 11V level. Things like hard drives won't
spin up, unless the full voltage is present.

The system also cannot start, or even beep, if Power_OK,
a signal on the main ATX cable, is not in the right state.
This is how the power supply announces "the buffet table
is now open". Without Power_OK, the signal is part of the
reset tree - the computer will remain with reset asserted,
if Power_OK isn't actually indicating things are OK.

Other onboard regulators, can also gate Power_OK. So if
something like VCore had a status pin, and VCore was
overloaded, that could prevent the system from coming
out of RESET.

The system can also be hobbled (no beeps), if the RESET
button is crushed in the ON state. On some computers, the
buttons are indeed that cheap, and they can be crushed like
that. The button ends up "pushed in", and visually looks
abnormal. The front buttons are a "floating" design, and
the body of the switch is isolated from the two wires
used by the switch.

So what would be a good minimum config ?

1) Motherboard, CPU, CPU_cooler, ATX12V power, main 24 pin power,
no RAM, no video card, no disks, remove other cards, connect SPKR,
connect Power button cable, disconnect RESET button cable,
disconnect front panel LEDs (if you're in the mood). The purpose
of clearing off the PANEL header, is so you can see that just the
minimum necessary electrical connections are in place. If that's
too much work, just pull off the RESET cable.

2) Power up, listen for beeps.

3) Do diagnostics of power supply, if you have the time,
patience and materials. Replace power supply, if you're
made of money, and swapping stuff is your preferred test
method. I keep one spare PSU (in my case, a nice Seasonic),
for swap. Once you become a home repairman, you end up
collecting some stuff for your junk rook, for future
debugging exercises.

HTH,
Paul

nothing snipped

Dell computers have 4 lights in the back. I forget what they do. Do
they do, in effect, some of what you're suggesting here?

Dave Doe wrote:
In article , , Rich
Hare says...

My wife's computer quit on her. Shut it down properly one night and
it refused to boot the next morning. No post, NADA.

Motherboard is an ASUS M3N78. Opening it up and I can see a light on
the motherboard, the fans are all working and I believe the hard
drives are spinning, but there is no signal to the montior (or a
second monitor that I tried).

I would like the opinion of the group whether the problem is:

Before you try anything serious, just try de-powering the motherboard
- ie. pull the power cord out, for about 15 seconds.

And then keep punching F8 or whatever it may be on the attempted boot up?

Dave Doe wrote:
In article , , Rich Hare
says...
My wife's computer quit on her. Shut it down properly one night and it
refused to boot the next morning. No post, NADA.

Motherboard is an ASUS M3N78. Opening it up and I can see a light on
the motherboard, the fans are all working and I believe the hard drives
are spinning, but there is no signal to the montior (or a second monitor
that I tried).

I would like the opinion of the group whether the problem is:

Before you try anything serious, just try de-powering the motherboard -
ie. pull the power cord out, for about 15 seconds.


A flat (zero volt) CMOS battery (CR2032 in socket)
can prevent some computers from booting. None of my
computers here, suffer from that.

Using a multimeter on the 20VDC scale, you can clip the
black lead onto an I/O connector screw (for ground),
connect the red probe to the top surface of the
disc-shaped battery, and determine whether it still
reads 3.0V or not.

The lowest acceptable voltage is 2.3V.

It will go from 2.3V to zero volts, in about three weeks of
being unplugged from the wall. So the battery knee, when no
other power sources are present, is about three weeks long.

Paul

Paul wrote:
Dave Doe wrote:
In article , , Rich
Hare says...
My wife's computer quit on her. Shut it down properly one night
and it refused to boot the next morning. No post, NADA.

Motherboard is an ASUS M3N78. Opening it up and I can see a light
on the motherboard, the fans are all working and I believe the hard
drives are spinning, but there is no signal to the montior (or a
second monitor that I tried).

I would like the opinion of the group whether the problem is:

Before you try anything serious, just try de-powering the
motherboard - ie. pull the power cord out, for about 15 seconds.


A flat (zero volt) CMOS battery (CR2032 in socket)
can prevent some computers from booting. None of my
computers here, suffer from that.

Using a multimeter on the 20VDC scale, you can clip the
black lead onto an I/O connector screw (for ground),
connect the red probe to the top surface of the
disc-shaped battery, and determine whether it still
reads 3.0V or not.

The lowest acceptable voltage is 2.3V.

It will go from 2.3V to zero volts, in about three weeks of
being unplugged from the wall. So the battery knee, when no
other power sources are present, is about three weeks long.

Paul

I respect your posts and I'm curious.
I've a W7 laptop with batteries that are 100% knackered and will only work
on mains power.
The CMOS battery is fine as it retains the date etc after the laptop has not
been booted up for 6 months.

In article , , Paul says...

Dave Doe wrote:
In article , , Rich Hare
says...
My wife's computer quit on her. Shut it down properly one night and it
refused to boot the next morning. No post, NADA.

Motherboard is an ASUS M3N78. Opening it up and I can see a light on
the motherboard, the fans are all working and I believe the hard drives
are spinning, but there is no signal to the montior (or a second monitor
that I tried).

I would like the opinion of the group whether the problem is:

Before you try anything serious, just try de-powering the motherboard -
ie. pull the power cord out, for about 15 seconds.


A flat (zero volt) CMOS battery (CR2032 in socket)
can prevent some computers from booting. None of my
computers here, suffer from that.

But unlikely. Sure the CMOS loses it's settings if the battery is
buggered. It'll use default values - and is usually evidenced by a Jan
1 date value. *Most* computers will still boot, and anyway, CMOS values
can be re-input.

I think it's still well worth de-powering the mobo - first, before
looking at POST/CMOS problems. Indeed, it's *then* that you want to
look at POST problems (they might have gone!).

--
Duncan.

Mr Pounder Esquire wrote:
Paul wrote:
Dave Doe wrote:
In article , , Rich
Hare says...
My wife's computer quit on her. Shut it down properly one night
and it refused to boot the next morning. No post, NADA.

Motherboard is an ASUS M3N78. Opening it up and I can see a light
on the motherboard, the fans are all working and I believe the hard
drives are spinning, but there is no signal to the montior (or a
second monitor that I tried).

I would like the opinion of the group whether the problem is:
Before you try anything serious, just try de-powering the
motherboard - ie. pull the power cord out, for about 15 seconds.

A flat (zero volt) CMOS battery (CR2032 in socket)
can prevent some computers from booting. None of my
computers here, suffer from that.

Using a multimeter on the 20VDC scale, you can clip the
black lead onto an I/O connector screw (for ground),
connect the red probe to the top surface of the
disc-shaped battery, and determine whether it still
reads 3.0V or not.

The lowest acceptable voltage is 2.3V.

It will go from 2.3V to zero volts, in about three weeks of
being unplugged from the wall. So the battery knee, when no
other power sources are present, is about three weeks long.

Paul

I respect your posts and I'm curious.
I've a W7 laptop with batteries that are 100% knackered and will only work
on mains power.
The CMOS battery is fine as it retains the date etc after the laptop has not
been booted up for 6 months.

There are actually two kinds of coin cells.

The CR2032 are not rechargable. If you pull the main battery
pack from a laptop, then there is no other power source,
so time keeping and the 256 byte CMOS RAM are powered
from the battery. Drawing 10uA, the battery lasts around
three years in this condition.

If the main battery pack is present, then the CR2032
does not need to be used, and will last for the
shelf-life period of ten years.

*******

The other kind of coin cell, is actually a rechargeable kind.
And the circuit around it, has to be designed to accomodate
that. Such cells don't have nearly the amp-hours, and
can only maintain an RTC timeclock for a handful of days.
If accompanied by a main battery pack of course, they
remain fully charged. I don't really have a good idea
how common those cells are in modern electronics. You
certainly won't find them in desktop systems. But for
laptops, where many times you cannot find or observe
the coin cell, it's harder to know how many use
that instead.

And the prevalence of "dead" computers, when the CR2032
hits zero volts, isn't that common. But in terms
of the fault tree analysis, it remains something
to be considered. When you've run out of other
excuses.

Just as power cycling of the mains, is a perfectly
valid test case for things like desktops. It covers
a number of intangibles.

Paul