RTC battery is low or CMOS checksum is inconsistent, press F1

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  1. #1
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    Default RTC battery is low or CMOS checksum is inconsistent, press F1

    Whenever i boot up my laptop i get this error message : "RTC battery is low or CMOS checksum is inconsistent, press F1 to reset date/time.

    the only thing I can do is restart... I looked up on the net, and someone said to recharge, the main battery for 8 hrs, will do it... NOT.

    another said to let it sit with charger on for 15 hrs, and have the laptop
    on at the same time... NO help there

    can anyone help me with this

  2. #2
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    Default Re: RTC battery is low or CMOS checksum is inconsistent, press F1

    Your CMOS battery might be dead. If the laptop is under warranty then send it in. If not, these batteries are not difficult to replace in Toshiba laptops, but will require you to disassemble you laptop. It is relatively cheap and easy to do.

    They seem to have a lifespan of ~ 3 years

  3. #3
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    Default Re: RTC battery is low or CMOS checksum is inconsistent, press F1

    Well, depends on how often you have power connected to your computer. The CMOS batteries depletes slower if your computer have an active power supply (i.e. it's plugged into an outlet, or it's running on power), so your mileage will vary. I've had computers with CMOS batteries lasting 5 years or more.

    In fact, this M200 is hitting its 4th birthday this August and it's CMOS battery is fine and dandy .

    But like TabbedOut stated, you'll have to replace the CMOS battery one way or another. Google around for instructions on how to deassemble your laptop if you want to do it manually.
    Toshiba Portage M200 | Pentium M 1.8Ghz (OC'd to 1.98Ghz) | 1.5GB RAM | 40GB HDD | WinXP:TE SP3 | nVidia GeForce Go FX 5200 32MB | SXGA+ (Broken screen )

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    Default Re: RTC battery is low or CMOS checksum is inconsistent, press F1

    Hi

    I too have a problem with the same error message but the laptop hasn't been used for a long time. I think the battery is still ok
    laptop battery could not be charged, first I thaught that the charger was broken, but i tested it on another laptop (same one :toshiba satellite A10) : it worked great.

    then I putted the battery of the other laptop inthe broken one, finaly i could start the system but it hangs on the error and it's telling me to press F1 to set date time but whatever button I press, nothing happens.

    when I put the charger in the broken laptop, the led is not ligting up green,
    the other laptops led is lighting up green. (with the symbol of the cable.)

    I think there is something wrong with the circuit between the charger and the power supply on the motherboard as I understood that the circuit between battery an motherboard uses another circuit.

    Please help

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    Default Re: RTC battery is low or CMOS checksum is inconsistent, press F1

    have you tried letting it charge overnight?

  6. #6
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    Default Re: RTC battery is low or CMOS checksum is inconsistent, press F1

    I know I've let my battery charge overnight. It will boot up but won't let me get past the rtc battery warning. I guess it looks like I've got to change it. I was wondering if anyone on here could tell me whether or not I could put a new motherboard in the body of an old Toshiba a45 s120. I really like the case and everything else but the motherboard is obviously outdated. Any help with this could be quite helpful. This way I could fix it myself and have an extra computer in the house. I'm willing to replace the heatsink, cpu and everything else. It's more of a pet project really. Thanks for all of your input.

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    Default Re: RTC battery is low or CMOS checksum is inconsistent, press F1

    Quote Originally Posted by makebae30 View Post
    I know I've let my battery charge overnight. It will boot up but won't let me get past the rtc battery warning. I guess it looks like I've got to change it. I was wondering if anyone on here could tell me whether or not I could put a new motherboard in the body of an old Toshiba a45 s120. I really like the case and everything else but the motherboard is obviously outdated. Any help with this could be quite helpful. This way I could fix it myself and have an extra computer in the house. I'm willing to replace the heatsink, cpu and everything else. It's more of a pet project really. Thanks for all of your input.
    I had this error on a Satellite Pro A40.


    RTC Battery is low or CMOS checksum is inconsistent. Press [F1] key to set Date/Time.

    I changed the CMOS battery (found one for a few pounds on Ebay), put it all back together and found the same error message was still coming up. Someone suggested on another forum, plugging in an external keyboard and then hitting F1 from that. I wasnt convinced this would work as I could force a reboot (ctrl, alt, del) using the laptop keyboard (so knew it worked) but tried it out of desparation. IT WORKED!!! Got into BIOS, set new date and time, unplugged keyboard and its fine every time now. Hope this helps others out...

  8. #8
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    Default Re: RTC battery is low or CMOS checksum is inconsistent, press F1

    Quote Originally Posted by steveP123 View Post
    I had this error on a Satellite Pro A40.


    RTC Battery is low or CMOS checksum is inconsistent. Press [F1] key to set Date/Time.

    I changed the CMOS battery (found one for a few pounds on Ebay), put it all back together and found the same error message was still coming up. Someone suggested on another forum, plugging in an external keyboard and then hitting F1 from that. I wasnt convinced this would work as I could force a reboot (ctrl, alt, del) using the laptop keyboard (so knew it worked) but tried it out of desparation. IT WORKED!!! Got into BIOS, set new date and time, unplugged keyboard and its fine every time now. Hope this helps others out...
    Did you need the external keyboard trick to boot every time after that, or did the new CMOS battery charge and start working properly?

    I've got Toshiba machines which are getting close to 10 years old, and I'm sort of biting my fingernails in anticipation of CMOS battery failures. In fact, I'm a little surprised it hasn't happened yet...

    This sort of advance information is probably going to be useful.
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  9. #9
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    Default Re: RTC battery is low or CMOS checksum is inconsistent, press F1

    <<...I've got Toshiba machines which are getting close to 10 years old, and I'm sort of biting my fingernails in anticipation of CMOS battery failures...>>

    ...In many units, the CMOS battery is only there to keep the system clock and some other functions running when the main battery is disconnected. If you never let the main battery run completely to exhaustion, the CMOS battery can be dead as a doornail (e.g., TC1100).

    Of course, this assumes that (as experienced by maya) your tablet doesn't have some other function running that would force you to get the CMOS battery replaced...

 

 

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