General discussion


CMOS Battery lasts 6 months

By badair ·
This has been going on for a few years now, I don't think that the system was this way to begin with, but the CMOS battery fails after about 6 months on a regular basis. This is a NEC Ready GT100, 450mHz, 256K ram, w/Fujitsu 12gb hd & running Win XP Pro, an upgrade from Win 98SE. Could there be a problem with the hardware, MB, or BIOS settings? I really hope to avoid fiddling w/the BIOS, as it is working now, just a pain in the tokas to change battery more often than I change my sox! Well, almost,ha ha.

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by wcp In reply to CMOS Battery lasts 6 mont ...

It?s most likely the motherboard.

Considering your system is 450MHz (I presume it is PIII), you have to ask yourself whether it is worth spending time and effort to resolve the problem.

Any replacement of HW will take at least 6 months to confirm.

My recommendation is to back up data and install a new system.

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by badair In reply to

Probably what I need to do.

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by A. G. In reply to CMOS Battery lasts 6 mont ...

I've run into something similar and ended up having to replace the board. Made the user very happy because they got a much faster machine out of the transaction.


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by badair In reply to

This system was made by NEC, (HP) I think, so I would need a MB that would be compatible, don't know where I could find one, however.

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by Frenchwood In reply to CMOS Battery lasts 6 mont ...

I would personally ditch the board. It's quite common for older boards to sap the CMOS battery.

Go out and get yourself a new system.

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by badair In reply to

Probably right, could always use for boat anchor!

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by TheChas In reply to CMOS Battery lasts 6 mont ...

I have one alternative to tossing the system.

Do you turn off the power to the system?

If so, that is why your CMOS battery is draining.

On an ATX system, the CMOS battery is only used when there is no AC line power to the power supply.

When the system is off, but power is still on, the 5 volt standby power from the power supply runs the real time clock and keeps the CMOS stable.

If you do keep AC power to the system, it is possible that the 5 volt standby circuit on the power supply is having problems.

With a volt meter, you can measure the standby line on the power connector.
If the voltage is less than 3.5, you need a new power supply

If the power supply is not the problem, and you really want to keep this system, there is one more work around.

First, you need excellent soldering skills.
When soldering on a computer motherboard, poor soldering skills or low quality soldering tools can permanently damage the motherboard.

Get a double cell AA or C size battery holder.
Find a place to mount the battery holder in the PC case.

Run wires from the battery holder to the CMOS battery socket.
Solder the wires to the correct battery tabs.

Install a pair of alkaline batteries.

You should be good for years.


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by badair In reply to

By golly there Chas, you may be onto something there, I'll just leave the little cropper plugged in & see what the heck happens.

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by korgmeister In reply to CMOS Battery lasts 6 mont ...

mostly the battery isnt the problem. i have a 6 year old pentium 3 desktop. it is non branded but the cmos battery is doing fine. maybe you want to reset the BIOS before doing anything else.

and you didnt tell us what is the problem actually, is it the clock not working? cant boot your window? or what is happening to your pc? please be precise


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by badair In reply to

This system is old enough to have barnacles on it! It boots ok, it's just that my lazy but has to change the stinkin battery every 6 mos. or so when the system looses the time & day.

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