taskbar clock

[Caryl]

I am writing this for a friend who cannot get the clock in the taskbar
to show the correct time when she turns her computer on. She corrects
the time on the clock, turns off her computer, reboots later, and the
time is the same as when she turned the computer off, not the current
time. The only recent change in her computer is updating to MS Office
2007. She uses Norton Security Suite 2009.

She has set the BIOS clock, synchonized with the Internet clock, and
replaced the CMOS battery. Any other suggestions for her?

Thanks.
Caryl

 

[VanguardLH]

I am writing this for a friend who cannot get the clock in the taskbar
to show the correct time when she turns her computer on. She corrects
the time on the clock, turns off her computer, reboots later, and the
time is the same as when she turned the computer off, not the current
time. The only recent change in her computer is updating to MS Office
2007. She uses Norton Security Suite 2009.

She has set the BIOS clock, synchonized with the Internet clock, and
replaced the CMOS battery. Any other suggestions for her?

Thanks.
Caryl

I'd still look at the CMOS battery. Could be she replaced it with an
expired and weak/dead one. Could be she inserted it upside down. Could
be the spring contact is corroded or oxidized. Could be she put in the
wrong battery so it doesn't make contact with the springs or clip or is
the wrong voltage. If she is less expert than you (and why she asked
for your help but you had to come here instead of immediately helping
her) then make sure someone more expert is physically inspecting the
motherboard to see what she did regarding the battery.

She via you never identified the motherboard maker and model. Look that
up and then read the manual on the correct CMOS battery to use. Also
make sure that someone at sometime didn't slap in a separate battery
velcroed elsewhere in the case and connected it to a 2-pin header on the
motherboard (if it's dead and shorted then a new wafer/coin battery on
the mobo isn't going to help) or that there isn't a jumper across the
2-pin CMOS reset or ext. batt. header on the mobo.

It is also possible the motheboard was physically damaged. Remember
that when asking her about entry inside the case that users often lie or
suddenly have a selective memory or they've let someone else have
physical access to the system case which isn't locked. A failed
component could also be the problem. As I recall, there is a capacitor
to isolate the battery (it isn't used when the PSU is powered up) and if
it's shorted then the output voltage from the coin cell will also be
shorted. A fried component that is open would prevent seeing the 3V to
keep alive the settings saved in the CMOS table. A shorted component
across the battery would reduce or zero its output voltage. The
standard discharge rate for a CR2032 coin cell is 0.4 mA and the max
discharge rate is 3 mA (see http://www.eemb.com/Li-MnO2_battery.html)
both of which are likely too small to fry open a short (i.e., they won't
heat up the shorted component enough to burn it apart to open it).

 

[Paul]

I am writing this for a friend who cannot get the clock in the taskbar
to show the correct time when she turns her computer on. She corrects
the time on the clock, turns off her computer, reboots later, and the
time is the same as when she turned the computer off, not the current
time. The only recent change in her computer is updating to MS Office
2007. She uses Norton Security Suite 2009.

She has set the BIOS clock, synchonized with the Internet clock, and
replaced the CMOS battery. Any other suggestions for her?

Thanks.
Caryl

I wonder if the clock has a broken quartz crystal ? Has the
computer ever been dropped or kicked ?

When the computer is running and the OS is booted, the time is
maintained by incrementing a variable stored in system RAM. In
other words, the OS uses a "software clock" and stops looking
at the RTC. The RTC is too slow, to be read regularly while
the computer is operating. The hardware interface is prehistoric.

When the system is about to shut down, the time is written back
to the RTC (or it can be).

The RTC contains (at least portions of it), are a ripple counter.
The value strobed into the flip flops would stay put, if the
32768 Hz clock generator signal was lost. Then, the next time
you boot the computer, and the OS reads the RTC and copies the
value into system memory, it's going to be reading the pattern
in those flip flops.

So your symptoms are consistent with a failed 32768 Hz quartz crystal
or the oscillator it is connected to. If the same value written
at the end of the day, is showing up the next morning, there there
are no pulses coming from the 32768 Hz source.

(too much emphasis on the older implementations here...)
http://en.wikipedia.org/wiki/Real-time_clock

The RTC and CMOS 256 byte RAM block, are powered by the CMOS battery.
If there was a total loss of power there, then the RTC would not work,
and the BIOS would forget key settings. On pre-built computers (like
my laptop from last year), I can only see one setting in the
BIOS, so there really isn't much to store in there any more. I'd
be hard pressed, to detect a change in the BIOS settings caused
by a battery failure.

If the RTC loses power, the BIOS initializes the flip flips to a well
known date and time. On older RTC designs, this might have been the
year 1970. But more modern computers, have been using "magic date"
values a bit above the year 2000.

In any case, if you saw a nice round value like Jan.1 1970, then that
would be telling you the RTC flip flops were uninitialized and had
been programmed by the BIOS. If the time matched the time at which
the computer was shut down, that tells me the RTC is powered all night,
but there is nothing feeding clock pulses to it. With no 32768 Hz
pulses, the flip flop based counter cannot advance.

The device on the left here, is a 32768, based on size and form factor.
They're used in digital watches. And you can find one next to the
Southbridge (where it is used by the Real Time Clock or RTC). On the
computer, the RTC draws about 10 microamps of current, while on a
digital watch, the figure can be as low as 2 microamps.

http://www.softwareforeducation.com/electronics/Circuits/QuartzCrystals.jpg

The circuit it connects to, looks like what is connected to pin 12 and 13
in this diagram. A quartz crystal has two legs, and there are a couple
small capacitors (measured in picofarads) in the circuit as well.

http://www.moty22.co.uk/img/lcd_counter.gif

Since the active part is inside a tin can, you can't look at it.
An ohmmeter would not be of much use either.

In practical terms, I'd expect to have to replace the motherboard.
On the one hand, you could probably dig up another crystal, but
there are a whole page of specs that have to match. At work, I've
always sought the assistance of a "quartz crystal expert", when
fiddling with those. Nothing bad would happen if you used the
wrong one, but perhaps it would fail again after some period
of time (if overdriven).

If you want, you can visually inspect the motherboard, and look for
the tin can and the two caps. They should be near the Southbridge,
and it isn't a good idea for the motherboard designer to put them
half way across the board. They should stay close to the equivalent
of pin 12 and pin 13 in that sample diagram, for best results.

Looking at my motherboard right now, I was able to immediately
spot the 32768, but the caps, for those I'd need a microscope.

Paul

 

[SC Tom]

I am writing this for a friend who cannot get the clock in the taskbar
to show the correct time when she turns her computer on. She corrects
the time on the clock, turns off her computer, reboots later, and the
time is the same as when she turned the computer off, not the current
time. The only recent change in her computer is updating to MS Office
2007. She uses Norton Security Suite 2009.

She has set the BIOS clock, synchonized with the Internet clock, and
replaced the CMOS battery. Any other suggestions for her?

Thanks.
Caryl

Does she have the correct time zone selected in Control Panel?

 

[Ken Blake, MVP]

I am writing this for a friend who cannot get the clock in the taskbar
to show the correct time when she turns her computer on. She corrects
the time on the clock, turns off her computer, reboots later, and the
time is the same as when she turned the computer off, not the current
time. The only recent change in her computer is updating to MS Office
2007. She uses Norton Security Suite 2009.

She has set the BIOS clock, synchonized with the Internet clock, and
replaced the CMOS battery. Any other suggestions for her?

I'll agree with what a couple of others have said: it's almost
certainly the battery. Either the new battery she installed is NG, or
she installed it incorrectly.

 

[Paul]

Paul wrote:

But why would that be necessary or desireable? (*unless* one were using an
internet based, system time updating app? If they weren't doing that, I
can't see reason why a software based clock running in the OS would be used
to update the RTC). Or maybe that's what you were getting at by "can be".

I don't know all the conditions under which the software clock is copied
to the RTC. The RTC has drift, whereas if NTP and the Internet are available,
the software clock can have very good properties, and give better results
than the RTC alone could. Under those conditions, syncing the RTC is
a good thing.

In that article, they mention the RTC in modern chipsets, is an
"emulation" of a Motorola MC146818. (The data sheet I have for it,
is dated 1984.) The emulation exists, to give wide compatibility
with various OS options (so they all know where to look). But the
location of the emulation, the speed of bus interfaces, limits
the utility of the thing. In fact, too much copying back and forth,
can lead to a systematic error.

Or be "close enough", I'd think. I think if I were in his/her shoes, I'd
give it a try. It sure could be a lot easier than replacing the MB. One
could probably find a reasonably comparable unit with some research.

One way to verify if the crystal oscillator is even working would be to use
an oscilloscope, before going to all the trouble of trying to replace it.

It helps if the chip in question offers a buffered output. Even
the ability to monitor a "1 Hz Output" pin would be better than nothing.

Years ago, I built my own digital watch, and the chip in there (running
at 32768 Hz), had a buffered output pin. That's where you connect
your oscilloscope or frequency counter. Then, you can twist the trimmer
cap, to get the thing right on 32768.0 . If you probe a quartz crystal
directly, the scope loading can throw things off. Even hand capacitance,
affects the frequency, and I'd have to move my hands away from
the circuit, before taking a reading.

On an Intel chipset, the buffered output pin is called SUSCLK. And
apparently, it doesn't run under all power states (presumably to save
power).

The computer implementation of the digital watch circuit, doesn't
have the trimmer, and there seems to be no intention to allow you
to tune it.

Paul

 

[Caryl]

I'd still look at the CMOS battery.  Could be she replaced it with an
expired and weak/dead one.  Could be she inserted it upside down.  Could
be the spring contact is corroded or oxidized.  Could be she put in the
wrong battery so it doesn't make contact with the springs or clip or is
the wrong voltage.

I am sorry that it has taken me so long to respond to yours and
everyone else's reply about the battery. I have passed on the
responses about this and hopefully she will check it out or find
someone to do so for her. Thank you all for your help.

 If she is less expert than you (and why she asked
for your help but you had to come here instead of immediately helping
her) then make sure someone more expert is physically inspecting the
motherboard to see what she did regarding the battery.

She asked for my help because she had tried several things herself and
still had a problem with the clock. I did not have any other
suggestions for her so came to this group because I had had good luck
in having questions occasionally answered in other Google groups
(Quicken, Firefox) in the past so thought that someone here could help
me and thus her.

Thanks again.

Caryl

 

[Caryl]

I wonder if the clock has a broken quartz crystal ? Has the
computer ever been dropped or kicked ?

When the computer is running and the OS is booted, the time is
maintained by incrementing a variable stored in system RAM. In
other words, the OS uses a "software clock" and stops looking
at the RTC. The RTC is too slow, to be read regularly while
the computer is operating. The hardware interface is prehistoric.

When the system is about to shut down, the time is written back
to the RTC (or it can be).

The RTC contains (at least portions of it), are a ripple counter.
The value strobed into the flip flops would stay put, if the
32768 Hz clock generator signal was lost. Then, the next time
you boot the computer, and the OS reads the RTC and copies the
value into system memory, it's going to be reading the pattern
in those flip flops.

So your symptoms are consistent with a failed 32768 Hz quartz crystal
or the oscillator it is connected to. If the same value written
at the end of the day, is showing up the next morning, there there
are no pulses coming from the 32768 Hz source.

(too much emphasis on the older implementations here...)http://en.wikipedia.org/wiki/Real-time_clock

The RTC and CMOS 256 byte RAM block, are powered by the CMOS battery.
If there was a total loss of power there, then the RTC would not work,
and the BIOS would forget key settings. On pre-built computers (like
my laptop from last year), I can only see one setting in the
BIOS, so there really isn't much to store in there any more. I'd
be hard pressed, to detect a change in the BIOS settings caused
by a battery failure.

If the RTC loses power, the BIOS initializes the flip flips to a well
known date and time. On older RTC designs, this might have been the
year 1970. But more modern computers, have been using "magic date"
values a bit above the year 2000.

In any case, if you saw a nice round value like Jan.1 1970, then that
would be telling you the RTC flip flops were uninitialized and had
been programmed by the BIOS. If the time matched the time at which
the computer was shut down, that tells me the RTC is powered all night,
but there is nothing feeding clock pulses to it. With no 32768 Hz
pulses, the flip flop based counter cannot advance.

The device on the left here, is a 32768, based on size and form factor.
They're used in digital watches. And you can find one next to the
Southbridge (where it is used by the Real Time Clock or RTC). On the
computer, the RTC draws about 10 microamps of current, while on a
digital watch, the figure can be as low as 2 microamps.

http://www.softwareforeducation.com/electronics/Circuits/QuartzCrysta...

The circuit it connects to, looks like what is connected to pin 12 and 13
in this diagram. A quartz crystal has two legs, and there are a couple
small capacitors (measured in picofarads) in the circuit as well.

http://www.moty22.co.uk/img/lcd_counter.gif

Since the active part is inside a tin can, you can't look at it.
An ohmmeter would not be of much use either.

In practical terms, I'd expect to have to replace the motherboard.
On the one hand, you could probably dig up another crystal, but
there are a whole page of specs that have to match. At work, I've
always sought the assistance of a "quartz crystal expert", when
fiddling with those. Nothing bad would happen if you used the
wrong one, but perhaps it would fail again after some period
of time (if overdriven).

If you want, you can visually inspect the motherboard, and look for
the tin can and the two caps. They should be near the Southbridge,
and it isn't a good idea for the motherboard designer to put them
half way across the board. They should stay close to the equivalent
of pin 12 and pin 13 in that sample diagram, for best results.

Thank you for all this interesting information. I have passed it on
and if she has any questions she or I will get back to you.

Caryl

Caryl