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lllao

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cmos battery

I have a two year old 486 PCI motherboard that hasn't been used much.  Recently, I have encountered trouble in booting the system.  I now get a message which says "CMOS battery low".  I replaced the 3V lithium battery and the system booted up fine.  After shutting down and booting up a second time 2 hours later, I received the CMOS battery is low message once again and have not been able to resolve this problem.  I've tested the old battery which proved to be dead.  I've tested the new battery awhich proved to be good. I've reset the CMOS jumper and this did not work.  What could it be.  The battery is good.
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gangclar

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start

My friend had same problem - battery had bad contakts and ...
burned through the motherboard (arcing). Check back side of your
motheboard.
One of two things.  First, as start said, it could be corrosion from the old battery (a white crystaline substance found around the battery connector).  If this is the case, check the surrounding ICs and other components for rusted pins.  

If there is some build up of acid, you can clean the board using a tooth brush and hot water with a bit of bicarbonate of soda disovled in it (that sounds harsh, but its ok - i do it all the time at work).

The other posibility is that the CMOS maybe dead - ie, not holding data.  I have seen this before and the only way to correct it is to replace the chip.  You can probably get that fixed for next to nothing at a local computer shop.

Hope this helps.


Stuart