Triple failure. Software? Hardware? Please help

micky wrote:
On Mon, 04 Jul 2011 09:19:13 -0500, GlowingBlueMist
wrote:

One other thing worth mentioning is that the life of the motherboard
battery is usually only rated for 5 years from date of manufacture. I

I think I've replaced it once, but that could be 5 years ago already!

have seen many strange things happen when one finally dies or gets too
low to fully drive the motherboard, including symptoms like you describe.

Does it need the mobo battery when the computer is plugged and
running?

When the computer is plugged in, and switched on at the back,
the +5VSB rail will be running. That rail runs, even when the
fans aren't spinning. The +5VSB takes the place of the
battery, as a source of current for the clock (RTC).
Another purpose of +5VSB, is to power the system RAM
sticks, while the system is in Standby Suspend To RAM (sleep
or S3).

The power supply has two halves. This shows how the
CR2032 coin cell battery fits in the picture.

CR2032 coin cell -----+
\___ Clock
/
ATX PSU ----- +5VSB supply ---------+
----- All other rails ----------- Motherboard power

If you unplug the computer from the wall, the CR2032 lasts
for three years. In that case, it is the sole source of
power for the clock.

If the computer is plugged in and switched on at the back, then
the +5VSB source is available and takes the place of the battery.
In that case, the battery can last for up to ten years (or
whatever its shelf life rating is). If +5VSB is present,
then no current flows out of the CR2032. As a result, the
battery lasts much longer (up to "shelf life" years).

The motherboard is not allowed to charge the battery. The current
flows out of the battery, but a diode prevents it from flowing
backwards.

The simplest alternative, if you own a multimeter, is to take
a reading off the top surface of the coin cell battery, with
respect to chassis ground. You can pick up a ground connection,
using a metal screw on an I/O connector in the I/O place area
of the computer. I clip on there with one lead of the
multimeter, and then use the red lead to make a voltage
reading from the top of the coin cell. Slightly above +3V,
is a good battery. Below 2.3V is a bad battery. The "knee"
of the battery is relatively sharp, so if the battery is
"on the decline" and near end of life, it'll be flat after
three or four weeks or so.

If you don't own a multimeter, you can remove the battery
and take it to your local Radio Shack. And they can test it
with a meter. But removing the battery is just a PITA,
and I'd just replace it on the spot. If I was going to
go to the trouble of getting it out of that damn socket,
I'd want to resolve the issue immediately, instead of
wasting the gas on a trip to Radio Shack for a test.

You should buy your replacement battery, from a store
with a high "turnover" rate. It is possible to find stores,
selling weak or flat batteries. And at the Mall of all places!

Paul

On 05/07/2011 06:57, GlowingBlueMist wrote:
On 7/4/2011 9:39 PM, micky wrote:
On Mon, 04 Jul 2011 09:19:13 -0500, GlowingBlueMist
wrote:

On 7/4/2011 8:42 AM, micky wrote:
On Sun, 03 Jul 2011 03:58:50 -0400, wrote:

micky wrote:
Triple failures? Hard Drive Data? Hard drive? Video Card? CPU?
Power Supply?

Last night, when I was running, as I have for at least 6 years, a
home-built computer with 1.5Gig memory and an 800MHaz CPU. All PATA,
no SATA.

[Based on the attempts in the header of one of the posts,
crossposted to alt.comp.hardware . I think that is where you
meant it to go.]

Thanks


One other thing worth mentioning is that the life of the motherboard
battery is usually only rated for 5 years from date of manufacture. I

I think I've replaced it once, but that could be 5 years ago already!

have seen many strange things happen when one finally dies or gets too
low to fully drive the motherboard, including symptoms like you
describe.

Does it need the mobo battery when the computer is plugged and
running?

The battery is relatively cheap. I would replace this one just as a
precaution due to the age of the motherboard, then tell the BIOS to
return to factory settings and go from there. If your BIOS has a
setting that sounds similar to Failsafe rather than factory original try
that one first.

A low battery can keep a system from booting. Fortunately it is easier
to swap the battery than it is to determine if it really needs replacing.

About the only definite proof is if the clock looses or resets the time
when the system is unplugged from the wall, but I have seen batteries
that were too low to allow a good boot while still barely maintaining
the clock.

I've even seen bad batteries make the clock run fast. Sounds
unlikely I know, but true (was an Asus P4C800E.)
Cheers,
--
Rob

GlowingBlueMist wrote:
A low battery can keep a system from booting. Fortunately it is
easier to swap the battery than it is to determine if it really needs
replacing.

Not if you have a voltmeter. If it reads 3V, it's fine.

On 7/7/11 9:38 AM, Bob F wrote:
GlowingBlueMist wrote:
A low battery can keep a system from booting. Fortunately it is
easier to swap the battery than it is to determine if it really needs
replacing.

Not if you have a voltmeter. If it reads 3V, it's fine.



It's always smart, IMO, to check a battery while it's under a load, not
just sitting out on your desk. :-)

--
Ken

Mac OS X 10.6.8
Firefox 5.0
Thunderbird 3.1.11
LibreOffice 3.3.2

Ken Springer wrote:
On 7/7/11 9:38 AM, Bob F wrote:
GlowingBlueMist wrote:
A low battery can keep a system from booting. Fortunately it is
easier to swap the battery than it is to determine if it really needs
replacing.

Not if you have a voltmeter. If it reads 3V, it's fine.



It's always smart, IMO, to check a battery while it's under a load, not
just sitting out on your desk. :-)


You can take an open circuit reading, and use the curve here to
estimate lifetime remaining. The upper left curve shows voltage
versus temperature and life. About 2.7V, as measured while
it's still sitting in the PC, tells you there is roughly 10% life
left.

http://www.panasonic.com/industrial/...032_CR2330.pdf

Paul

Hi, Paul,

On 7/7/11 11:18 AM, Paul wrote:
Ken Springer wrote:
On 7/7/11 9:38 AM, Bob F wrote:
GlowingBlueMist wrote:
A low battery can keep a system from booting. Fortunately it is
easier to swap the battery than it is to determine if it really needs
replacing.

Not if you have a voltmeter. If it reads 3V, it's fine.



It's always smart, IMO, to check a battery while it's under a load,
not just sitting out on your desk. :-)


You can take an open circuit reading, and use the curve here to
estimate lifetime remaining. The upper left curve shows voltage
versus temperature and life. About 2.7V, as measured while
it's still sitting in the PC, tells you there is roughly 10% life
left.

http://www.panasonic.com/industrial/...032_CR2330.pdf

Chart saved to the hard drive.

That would take a much more accurate volt meter than I have. :-)

But, my suggestion works for any battery. I learned that years ago when
in aircraft mechanics school.

--
Ken

Mac OS X 10.6.8
Firefox 5.0
Thunderbird 3.1.11
LibreOffice 3.3.2

Ken Springer wrote:
Hi, Paul,

On 7/7/11 11:18 AM, Paul wrote:
Ken Springer wrote:
On 7/7/11 9:38 AM, Bob F wrote:
GlowingBlueMist wrote:
A low battery can keep a system from booting. Fortunately it is
easier to swap the battery than it is to determine if it really needs
replacing.

Not if you have a voltmeter. If it reads 3V, it's fine.



It's always smart, IMO, to check a battery while it's under a load,
not just sitting out on your desk. :-)


You can take an open circuit reading, and use the curve here to
estimate lifetime remaining. The upper left curve shows voltage
versus temperature and life. About 2.7V, as measured while
it's still sitting in the PC, tells you there is roughly 10% life
left.

http://www.panasonic.com/industrial/...032_CR2330.pdf


Chart saved to the hard drive.

That would take a much more accurate volt meter than I have. :-)

But, my suggestion works for any battery. I learned that years ago when
in aircraft mechanics school.


You'll get more of the lifetime of the battery, if you just
meter it in the PC. A "light bulb" test, might cause you to
chuck the battery, while 30% life remains.

Paul

Ken Springer wrote:
On 7/7/11 9:38 AM, Bob F wrote:
GlowingBlueMist wrote:
A low battery can keep a system from booting. Fortunately it is
easier to swap the battery than it is to determine if it really needs
replacing.

Not if you have a voltmeter. If it reads 3V, it's fine.



It's always smart, IMO, to check a battery while it's under a load, not
just sitting out on your desk. :-)

True enough! Sometimes the open circuit voltage can be close to normal,
but it's still bad (when tested under load, due to excessive internal
resistance in the cells).

Don't tell anyone, but I sometimes test these dinky batteries directly (but
briefly!) with an ammeter (i.e., for their short circuit current value).

Caveat: I said dinky battery. Don't even think about trying this on a car
battery (at least not with most meters). :-)

Bill in Co wrote:
Ken Springer wrote:
On 7/7/11 9:38 AM, Bob F wrote:
GlowingBlueMist wrote:
A low battery can keep a system from booting. Fortunately it is
easier to swap the battery than it is to determine if it really needs
replacing.
Not if you have a voltmeter. If it reads 3V, it's fine.


It's always smart, IMO, to check a battery while it's under a load, not
just sitting out on your desk. :-)

True enough! Sometimes the open circuit voltage can be close to normal,
but it's still bad (when tested under load, due to excessive internal
resistance in the cells).

Don't tell anyone, but I sometimes test these dinky batteries directly (but
briefly!) with an ammeter (i.e., for their short circuit current value).

Caveat: I said dinky battery. Don't even think about trying this on a car
battery (at least not with most meters). :-)


But the load on the CMOS cell is 10 microamps, meaning
the open circuit voltage is very close to the voltage when
a 10 microamp load is present. A load test is unnecessary.
Just using a multimeter reading, and the curve from the datasheet,
is enough to predict lifespan.

Even with a high internal cell resistance, 10 microamps times
that resistance is nothing.

As a matter of fact, there is a 1K ohm resistor in series
with the CMOS coin cell, as a current limiter. That should give
you some idea how little they care about cell resistance. A
ceramic cap is placed at the end of the circuit, where it
joins to the Southbridge, to provide good transient response,
which happens mainly when the computer is running. There are
next to no transients when the battery is being called on
to deliver the 10 microamps.

Paul

On 7/7/2011 8:38 AM, Bob F wrote:
GlowingBlueMist wrote:
A low battery can keep a system from booting. Fortunately it is
easier to swap the battery than it is to determine if it really needs
replacing.

Not if you have a voltmeter. If it reads 3V, it's fine.



Not always...
If you are using a digital voltmeter, it's input impedance is so high
that a crappy battery can read 3.0 v, but put even a small load (like
the mobo CMOS) and it can drop badly.
(DVMs basically put no load on the battery)

Best way to check a CMOS battery is with one of those "real cheap"
analog meters (one that's rated 2Kohms per volt is perfect for this).
That puts a reasonable load on said battery.

Best bet, replace it anyway with a new one (preferably from a source
that has fairly fresh ones).

I've been shot in the foot by CMOS batts to even worry about checking
voltage.

--
"**** this is it, all the pieces do fit.
We're like that crazy old man jumping
out of the alleyway with a baseball bat,
saying, "Remember me mother****er?"
Jim “Dandy” Mangrum