Computer RTC looses 1 second every 4.5Hours

[gmv]

Hello,

I have a Toshiba laptop which keeps terrible
time and I was just wondering if anyone has
successfully adjusted the RTC in a laptop
to keep better time. I understand these quartz
clocks usually use an oscillator tuned to
32768Hz and if properly adjusted they keep pretty
good time but the trouble is that few if any of
the companies turning out these clocks actually
adjust them.

At the moment i set my clock fast by 6 seconds and
allow it to drift across zero for 6 additional
seconds this gives me 54 hours of usable RTC time.
But I would very much like to reduce that error.

The laptop of which I speak is a
Toshiba Satellite 205CDS.


--
Regards;
gmv

 

[Anthony Fremont]

"gmv" <noemail@please.123> wrote in message
newsA7Od.27461$C24.9241@attbi_s52...

Hello,

I have a Toshiba laptop which keeps terrible
time and I was just wondering if anyone has
successfully adjusted the RTC in a laptop
to keep better time. I understand these quartz
clocks usually use an oscillator tuned to
32768Hz and if properly adjusted they keep pretty
good time but the trouble is that few if any of
the companies turning out these clocks actually
adjust them.

At the moment i set my clock fast by 6 seconds and
allow it to drift across zero for 6 additional
seconds this gives me 54 hours of usable RTC time.
But I would very much like to reduce that error.

The laptop of which I speak is a
Toshiba Satellite 205CDS.

Are you talking about the time according to windos or the actual CMOS
time? Win98 and earlier (not sure about xp) get the time from the CMOS
only at startup. After that, windos keeps it's own time using timer
tick interrupts. If anything (and there are many things that can do
this) causes windows to miss handling a timer tick, you lose time. I've
seen device drivers and applications cause this to happen.

 

[gmv]

"Anthony Fremont" <spam@anywhere.com> wrote in message news:25dOd.23568$sr1.13897@fe2.texas.rr.com...

"gmv" <noemail@please.123> wrote in message
newsA7Od.27461$C24.9241@attbi_s52...
Hello,

I have a Toshiba laptop which keeps terrible
time and I was just wondering if anyone has
successfully adjusted the RTC in a laptop
to keep better time. I understand these quartz
clocks usually use an oscillator tuned to
32768Hz and if properly adjusted they keep pretty
good time but the trouble is that few if any of
the companies turning out these clocks actually
adjust them.

At the moment i set my clock fast by 6 seconds and
allow it to drift across zero for 6 additional
seconds this gives me 54 hours of usable RTC time.
But I would very much like to reduce that error.

The laptop of which I speak is a
Toshiba Satellite 205CDS.

Are you talking about the time according to windos or the actual CMOS
time? Win98 and earlier (not sure about xp) get the time from the CMOS
only at startup. After that, windos keeps it's own time using timer
tick interrupts. If anything (and there are many things that can do
this) causes windows to miss handling a timer tick, you lose time. I've
seen device drivers and applications cause this to happen.

I am fetching my times from the RTC which you
call CMOS. I understand that the RTC has its own crystal
oscillator at about 32768HZ which is pretty much
the same as for most digital watches. It is my
awareness that these quartz devices will keep very good time
if only they are adjusted at time of manufacture
but in most cases the companies will slap things together
according to design and do no calibration whatsoever of these time pieces.
All I want to do is calibrate the RTC for my computer.


>

 

[polleke]

in some cases there is a small adjustable capacitor close to the
crystal, just turn it.