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View Full Version : PC Clock goes back a day



creative42
14-10-2012, 09:34 PM
The clock on my PC (yep, bottom right-hand corner) has very recently started to show the incorrect date and time. For example, earlier today when I booted it up, the clock showed something like 13/10/2012, 21:54, when actually it was 14/10/2012, 11:01 (roughly, you get the idea).

Could it be a flat CMOS battery as my PC is now 4 years old? Or is there something in the BIOS I could or should check? Also, if you change the CMOS battery, do you lose the BIOS settings?

Any help gratefully accepted.

Kelron
14-10-2012, 09:53 PM
It probably is the battery. Do you ever turn your PC's mains connection off?

MiniMatt
15-10-2012, 01:49 PM
Have to say my first hunch would not necessarily be the cmos battery, as typically when that goes the date will get reset to Unix time (1st Jan 1970) or some similar waaay out date. Going back just a day doesn't sound particularly like a battery symptom - I'd be more inclined to think, at first guess, that your OS is picking up time from an icky time server.

How you check that is going to depend on OS, Win 7 (and I *think* Vista), click on the clock, click "change date & time settings" and then go to the "internet time" tab. For internet time servers, "time.windows.com" is a safe enough choice or most universities run one, your ISP probably runs one too. Or for old schoolers, the DOS command "net time" provides a wealth of options.

creative42
15-10-2012, 09:14 PM
It probably is the battery. Do you ever turn your PC's mains connection off?

Yes, I turn it off at the mains.


For internet time servers, "time.windows.com" is a safe enough choice

Yep, this is the server my PC gets the time from. Maybe I should just try one of the others that are listed?

Danny252
15-10-2012, 09:39 PM
Is your timezone set correctly? If your computer thinks you're GMT-11, that might be doing it.

creative42
16-10-2012, 09:48 PM
Bought a new CMOS battery today, and going try that - I assume I won't lose my BIOS settings??? Will check my timezone first, but seems strange as only in the last week has it started it doing it, and I've not changed any setting myself.

Kelron
16-10-2012, 09:58 PM
Turning it off at the mains will cause this, eventually. If you leave it plugged in it will receive enough power to keep the time. If it's not receiving power from the mains it's draining the battery, and it won't be keeping time correctly overnight. So you're turning it on the next morning and it's still showing the time from the previous night.

If you replace the battery while the system is on at the mains (with the PC off, of course), you won't lose the settings. Obviously you wouldn't normally want to work on a computer with the mains on, but you will lose your settings otherwise.

creative42
16-10-2012, 10:03 PM
Turning it off at the mains will cause this, eventually. If you leave it plugged in it will receive enough power to keep the time. If it's not receiving power from the mains it's draining the battery, and it won't be keeping time correctly overnight. So you're turning it on the next morning and it's still showing the time from the previous night.

If you replace the battery while the system is on at the mains (with the PC off, of course), you won't lose the settings. Obviously you wouldn't normally want to work on a computer with the mains on, but you will lose your settings otherwise.

Thanks for that! It's more awkward than I originally thought to change such a simple thing like a CMOS battery - it is under the graphics card. Doh! I'll give it go though, as I don't want my BIOS settings disappearing!

Boris
18-10-2012, 09:10 PM
For NTP servers, I prefer the bunch hosted by the NTP pool project. You can set it by region, so if you're in the UK, connect to uk.pool.ntp.org

And yes, you should replace the battery. Even if you have to remove your graphics card it should be a 5 minute job tops and it can save you a lot of troubles later on.

creative42
20-10-2012, 02:54 PM
Finally fitted a new CMOS battery yay! Left it too late though, and had already lost my settings. Have got them back to how they should be though I think. Will know next time that it starts with the clock going a bit awry. Thanks for all the advice.

ianjones
05-11-2012, 01:33 PM
did you sort that issue?

creative42
05-11-2012, 06:15 PM
did you sort that issue?

Yes, the clock now keeps the correct time, and I managed to get my BIOS settings back to how they should be by a bit of Googling.