# Toshiba A45 S250 - RTC Battery is low or CMOS checksum is inconsistent



## m_martin

Hi I have a Toshiba A45 S250 and its been off for a long time. I recently turned it on and got this message:

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

So far I have tried to 
*leave it on for 24 hrs to charge the RTC battery

*I've purchased a new RTC battery

*Removed the CD drive, Hard drive and main battery then turn it on...get the same message

I cannot access the bios or set the date when I push F1 nothing happens. I've tried to access the BIOS but it just stays at the Toshiba screen and nothing happens.

Please help!


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## Madcatz

Most toshibas are F2 to enter the BIOS, or if that one has the differnet BIOS, you would need to hold down ESC while powering the unit on, then a msg will come up saying to press such key to check the system, you press teh key and it goes into the BIOS.


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## m_martin

When I hold down the ESC key while powering on the laptop it just displays:

**** RTC battery low or CMOS checksum is inconsistent ****

When I hold down the F2 key while powering on it just displays the Toshiba logo and looks like it is trying to get to the bios but it does nothing after that....Im starting to think maybe the motherboard has gone bad is there anything else I can try?


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## m_martin

is there anyone else that can help?


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## Madcatz

ok, yours is the ESC key then F1 to access the BIOS. So you've been doing it right. Could be a few things since you can't access the BIOS, first, does the F1 key work in windows? Deffinately make sure this works, if F1 isn't working in windows then test some other keys, you just may need a new keyboard. If F1 does work, then try this:

Hit F12 while powering on does it give you the boot option menu? Yours I belive will have the 5 or 6 icons at the bottom of the screen you can arrow through.

If you can access the boot menu and select what to boot from, then I'd try and download a BIOS update from toshibas website, burn that to a cd or a floppy disk (only if you have a floppy drive or USB floppy drive to use) and try to update the BIOS since it may be corrupted.

Update it, then see if you can access it and set the time and date.


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## m_martin

Thanks for replying:grin:

The F1 Key was not working like you said. I was able to get to the Boot option menu and use the arrow keys to choose the CD option, I burned a CD of the BIOS update, but when I hit enter it gave me that same message about the RTC battery..so I plugged in a usb keyboard and tried to use F1 and it WORKED!! I set the date and then updated the BIOS. Then I was able to get Windows running again..Thanks Madcatz!ray:


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## Madcatz

Great to hear 

I would also check the rest of the keys on the keyboard to make sure they all work, sometimes an entire row of keys will go out on them.


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## zerostrider

Thank goodness for Google, and also for this forum here. I'm not very good with computers... I fixed this exact error message on my Toshiba laptop which is over 5 years old now (I haven't used it for about 8 months)... simply by plugging in a separate keyboard, which THEN let me press F1! I entered in the new date and time and it completely loaded the OS desktop again. 

Thank goodness because I have a couple other computers that have been having issues and I wanted to be able to fix at least ONE of them.

I am just posting this message because downloading the new BIOS onto a CD and then booting from that may NOT be necessary.

But I think my laptop is on its last legs. I ought to buy an external harddrive soon to export all my data onto.


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## ubuntuuser

Thank you! I have a Toshiba Dynabook Satellite J12 that has not been powered on for 6 months, after that it displayed this error: RTC battery is low or ... . After reading this I pluged in a PS2 keyboard and was able to press F1 and entered BIOS (actually I had already planned to do just that, since my laptop keyboard was broken). After changing date and time everything returned to normal.


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