I've recently purchased a Sony Vaio VGN-SZ120P in US.

The system clock seems to be dead. It does not run even when my laptop
is turned on i.e. it will show the time and date of the last time I
set the correct time on Win XP. Also If I enter BIOS setting, the clock
is not running. I'm not sure if it's a cmos battery problem or a faulty
real time clock.

Do you know if the internal clock (real time clock) takes its energy
from other source than the battery when the laptop is on and plugged
in? If that's true, then I have a hardware problem (remember the
clock is dead even when the laptop is on).

It's really important for me knowing this since I bought the laptop
in US (it's under warranty) but I don't live in US and is really
hard to take it there for repair. So if it's a battery problem it's
not big deal, I can change it in my country, but if there is a
motherboard problem...

Thanks in advance

On 30 Nov 2006 14:01:25 -0800, "jpberta" <jpberta (AT) hotmail (DOT) com> wrote:

Most Real Time Clock (aka Time Of Year Clock) implementations source power
from the motherboard Standby power rail, as long as either the unit is
connected to an AC source, or is operating on the main batteries. If AC in
unavailable and the main batteries have run down, the RTC will resort to
taking power from the cmos battery.

It's possible to have the cmos memory maintain data properly while the RTC
fails - if you got a marginal cmos battery. If you can find that battery, it
should be putting out roughly 3V, cmos/rtc chips working down to around 2V
these days, that provides a suitable allowance for a diode OR with the standby
supply rail. The battery thus needs to make at least 2.7v, I'd think, lest
things start going pear shaped...

/daytripper