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I am running crunchbang (#!) linux on my netbook (which uses an ubuntu core).

When I start my netbook (running on battery) I am prompted to reset my Bios settings. This causes some problems with my clock, since it is reset to factory default settings. Which in turn causes problems with fsck and my OS doesn't boot properly on normal mode.

What I did so far was loading the OS in recovery mode, letting fsck fix some timestamps in manual mode and eventually it will let me through to the OS. Logged in I updated my clock and I don't get other errors.

The strange thing is that if my laptop is plugged into AC (not using the battery) and I in a previous session had updated the clock and all, it wouldn't prompt me to reset the Bios settings. But as soon as I boot it from battery it prompts me again. Which could mean it is a hardware problem. Some capacitors leaking power. But it is only on start up, I don't have strange drift rates or jumps in my clock after I updated it manually with a server.

I am unsure what causes my problem, whether it might be simply a hardware failure or due to some bug in my OS. Has anyone experienced the same problem?

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1 Answer 1

up vote 2 down vote accepted

You laptop's motherboard battery is probably dead, replace it and this will go away.

The battery is responsible for keeping the real time clock on and making sure that your BIOS settings are kept between power cycles.

If a computer keeps asking for setting up your BIOS settings and your clock resets to factory on each boot there can only be 3 things related to that:

  • The battery is dead (no battery means the system will boot with default BIOS settings / clock), replace it if necessary;
  • Your clear CMOS jumper on the motherboard (if present) is set to on (erases settings / clock on each reboot), switch the jumper to the off position and your computer will save BIOS settings / clock between power cycles;
  • You motherboard is defect and its not saving the BIOS setting / clock, in this case you need to replace the motherboard.

The catch here is that not only your clock is reset but also your BIOS settings, if it was just something messing with the clock the BIOS settings would not be erased.

Some laptop motherboards have replaceable batteries, others have chargeable ones soldered in to the PCB. With some luck you have the first type and can swap it in a few minutes (probably one of the covers on the bottom side of the laptop allow access to it), if you have one of the 2nd type you can still replace it with simple soldering skills or ask any electronics company around where you live to to so for you.

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The battery was my suspicion as well. Thanks for confirming :) –  Pitt Nov 25 '11 at 15:49
    
Unless proven wrong always go for the more simple ;) Thick the check mark on the answer if not proven wrong! Regards. –  Bruno Pereira Nov 25 '11 at 15:51
    
Ubuntu actually automatically updates the date and time regularly. Turn it on and it will help you. –  ThePiercingPrince May 24 '13 at 11:57

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