my laptop (PC) clock has been losing time for the past week or so. i looked it up and it seems that the CMOS (motherboard) battery might be failing. i found an application to sync my clock's time up with servers on the internet and it is working fine now, but do you think i should still take it in to Pantip to get the battery replaced or is this a small thing?

The CMOS battery runs a trickle charge to the CMOS memory which the non-volatile type, that is to say, it retains the data even if the PC has been powered off. The PC need to have access to that data when you first power on so that it can configure all the BIOS settings and components (BIOS = Basic Input, Output System). Once those have been verified, the BIOS hands over control to the operating system and providing everything is in order, the machine boots to the desktop.

You could try leaving the PC running for 24 hours which should be enough to recharge the CMOS battery if it's still OK. But if it continues to lose time, or you start to see CMOS errors, then it's time to replace it. Instructions on how to do that @ hxxp://www.computerhope.com/issues/ch000239.htm

cmos batteries aren't rechargeable so when it's dead, it's time to replace it.

you should have it replaced as you don"t only lose time and date but also personal bios settings if any.

Its time to replace battery, they don't put things uncessary.

thanks for the advice... can anyone recommend a good shop in Pantip to take it for repair?

thanks for the advice... can anyone recommend a good shop in Pantip to take it for repair?

Global Solution- 4th floor. they are on the right hand side (looking up as you walk in the front of Pantip) overlooking the atrium.

thanks

I've never actually had a computer long enough for the CMOS battery to die out but they should be cheap to replace. They look like oversized watch batteries.

Hi

Change it yourself - it's very easy to do. First of all go and get a new battery - if you change it quickly enough you will not lose BIOS settings such as HDD parameters etc. The battery used in 99.9% of all mainboards is a lithium button cell of the precise type "CR 2032", you can get this in ANY shop that sells watches or cameras (or supermarkets like Tesco Lotus or Big C). Do NOT buy these at Panthip - while cheaper, they seem to be from very old stock and don't last longer than a couple of months! At a watch shop you usually pay some 50-80 Baht, 39 Baht at Tesco Lotus. Go for "Energizer" or "Panasonic" brands.

Back home, shut down the computer, unplug the power cord (and the monitor), then open the side of the computer case (it's easier when you lay it flat onto it's other side) and look over the motherboard, the BIOS battery (CMOS Battery) is easy to see. Take it out and put the new one in, done.

Now if you are lucky you did this fast enough and all settings are still intact, if not you may have to set the system time (some computers refuse to boot if it's not done!), for everything else you can "load BIOS defaults" and it will work. But likely you won't have to do anything (BIOS data usually stays intact for some 10-30 seconds without battery, but i don't know for how long if the battery is already dying).

Best regards.....

Thanh

my laptop (PC)

Change it yourself -

open the side of the computer case (it's easier when you lay it flat onto it's other side)

Laptops can be a pain to open (depending on brand/model) to get to the battery and not recommended if not experienced in doing so.

Ooops......

Sorry, i really managed to overlook the word "laptop". Indeed, if it's a laptop, NOT recommended to do it yourself.

Apart from that, laptops don't seem to always have a CMOS battery in first place - i've got a taken-apart one right here in front of me and there is no battery anywhere to be found. This is a Fujitsu-Siemens but i also had an Acer apart that didn't have any form of battery anywhere inside, i guess those work with gold-cap type capacitors or similar.

Best regards.....

Thanh

Sorry, i really managed to overlook the word "laptop".

Been there, done that.

i guess those work with gold-cap type capacitors or similar.

Could be using super caps in the more "luxury" models.