Naked Science Forum
Non Life Sciences => Geek Speak => Topic started by: Lynda on 07/03/2010 20:47:31
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This morning I put on my PC and noticed the time was an hour behind. Puzzled, I wentn into Control Panel and found the thing to adjust the time.
I have noticed it is slightly losing again. I know the proper time is around 20:45 but my computer says it is 20:42 on the bottom-right-hand of the screen.
Can anyone throw any light on this? I have XP and Avast anti-virus. I normally use Google Chrome but have IE8 and Firefox on but this seems unrelated to browsers!
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http://www.thenakedscientists.com/forum/index.php?topic=26529.0
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Thanks, RD, for directing me to the previous thread. It must be as a result of me trying to be eco-conscious and turning my PC off when not in use! It is only mildly slow at the moment. (Saying 19:20)
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If it is anything to do with the battery could it be as a result of recent nights being extremely cold? My terraced house front room is poorly insulated and has no central heating - just an electric convector heater which is on when I am here.
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The battery is "user replaceable" but I'd get a PC shop to do it if I were you
The memory and real-time clock are generally powered by a CR2032 lithium coin cell. These cells last two to ten years, depending on the type of motherboard, ambient temperature and the time that the system is powered off, while other common cell types can last significantly longer or shorter periods, such as the CR2016 which will generally last about 40% as long. Higher temperatures and longer power-off time will shorten cell life.
When replacing the cell, the system time and CMOS BIOS settings may revert to default values.
http://en.wikipedia.org/wiki/CMOS_Battery
http://en.wikipedia.org/wiki/Real-time_clock
Flashing the BIOS
Where the BIOS is stored in rewritable memory, flashing the BIOS is overwriting the BIOS contents with a BIOS image. This is done to update the BIOS to a newer version either to fix specific bugs, support newer hardware, or fix a damaged BIOS. However, care must be taken when doing this because if it is not done correctly, the system will usually become inoperable.
http://en.wikipedia.org/wiki/BIOS#Flashing_the_BIOS
I have "flashed my BIOS", (they can't touch you for it [:)] ), but I did pray beforehand asking that that the electricity supply would not fail when I did it as such a failure would cause the computer to crash mid-BIOS-installation and could make the computer unusable thereafter.
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The basic frequency for the internal is derived from a 32,768 Hz crystal such as is used in a clock or watch, if you have a poor one it may well be several seconds a day adrift.
If you have any means of checking the exact frequency you can adjust it by fitting a O-50 pF trimmer capacitor either in series or parallel depending whether it is high or low or simply get a better one.
I am assuming that the battery is OK and you are confident taking a soldering iron to your mother board.
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Many thanks for your advices. Sorry, but I daren't touch the inside of my computer - it is the only one I have! My brother is good at I T but he lives in Shropshire and I live in Norwich so I hardly ever see him.
The time on the PC has kept up today - so I may well leave it alone rather than messing around with it!
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One additional sideeffect of low CMOS battery is not only the slowdown of the clock on your computer, but it can also make your screen flicker chaotically, especially if it gets really low on energy.
Tried it on my own computer. Oddly enough, when changing to MS-DOS, no flickering occurs ;)
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There are a number of ways to set the clock to the standard time via NTP. If you are using Windows have a quick google around and see how to configure it. Mac and Linux have this built in, you just need to enable it, and set it to check at most once a day. Any more often and you are going to cheese off the admin of one of the free Stratum 2 servers on the internet For more info go to www.ntp.org
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One additional sideeffect of low CMOS battery is not only the slowdown of the clock on your computer
Please see the thread referred to earlier: a low CMOS battery will not cause the clock to slow down.
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One additional sideeffect of low CMOS battery is not only the slowdown of the clock on your computer
Please see the thread referred to earlier: a low CMOS battery will not cause the clock to slow down.
Right. I think it's most unlikely to be caused by the battery. I would suspect the crystal that provides the timing reference for the real time clock is running a bit slow - that's assuming RTC's still use external crystals.
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Thanks for the advice. I think my PC battery was a bit low - a few days ago I turned it on in the morning and a screen came up with the information that my CM02 battery was low and was told to hit F2 and F1 - then select something else (forgotten which) in order to continue with the usual start up.
I left the computer, unusually for me as I am normally mean with electricity use, on standby when I went out that day in order for the battery to recharge. It seems much better now - even the time is keeping up (21:39 at moment).
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I think my PC battery was a bit low - a few days ago I turned it on in the morning and a screen came up with the information that my CM02 battery was low and was told to hit F2 and F1 - then select something else (forgotten which) in order to continue with the usual start up.
I left the computer, unusually for me as I am normally mean with electricity use, on standby when I went out that day in order for the battery to recharge. It seems much better now - even the time is keeping up (21:39 at moment).
I don't think the CMOS battery is rechargeable: the computer clock kept good time on standby because it it not using the CMOS battery whilst on standby.
It's when your computer is off that it relies on the battery to keep time and remember other important settings (BIOS).
If you got an computer error message saying the CMOS battery is low then you should have it replaced.
Have a PC repair shop do it, as I mentioned above the computer may forget important settings when the battery is removed and these will have to be reprogrammed after the new battery is fitted.
The CMOS battery is dead or dying
Explanation: The system is exhibiting behavior that implies that the CMOS battery is dead. This can include lost CMOS settings, the real-time clock losing time, or of course dead battery warnings at boot time.
Diagnosis: On an older PC, it is normal for the CMOS battery to fail at some point in time. They usually last for many years, with over five years being the norm, at least on older machines. Nobody knows for sure how newer machines will fare. On a new motherboard, this sort of message is a sign of a defect, although you shouldn't worry about it if it appears only the very first time the board is powered up. The solution is replacing the battery, and this can be an either easy or impossible task, depending on how much thought the motherboard manufacturer put into the design.
http://www.pcguide.com/ts/x/comp/mbsys/cmos_BatteryFailing.htm
NB: You should have a backup copy of all the data on your computer's hard-drive on an external hard-drive, so if your computer breaksdown is damaged or stolen you will still have a copy all your personal data, OS, and other software.
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One additional sideeffect of low CMOS battery is not only the slowdown of the clock on your computer
Please see the thread referred to earlier: a low CMOS battery will not cause the clock to slow down.
Yes, my apologies. You are obviously right. Nonetheless, what really matters in this case is that the CMOS is responsible for the wrong time/date, flickering of screen, boot time warnings etc.