"CMOS Checksum Error - Defaults loaded" on my Abit BX6

[MrBond]

Back this summer, when I upgraded, I pulled out my abit BX6 and built my mom a PC with it, It was out of a system for probably a month before I got it put back together. Ever since then, when I boot up, I'm getting the error messege during post "CMOS Checksum Error - Defaults Loaded". I can bypass it and everything works fine (except the date is messed up until she resets it). Is this due to a dead battery on the board? Could being unpowered for over a month drain it? If so, does anyone know what kind of battery it is offhand, so I can pick one up on my way home, rather then driving home, checking, then coming back here to get a battery. Thanks in advance

 

[sadb0i]

i dont think its the battery...it should come up with a different error message for that....anyway...
have you set the bios/setup defaults yet rather than bypassing them...

 

[obenton]

Battery. Take it out to get the number - it's CR something, as I recall. You can buy one at Radio Shack or Walmart for about a dollar.

 

[bozo1]

It -may- be the battery but I doubt it.

That message is going to continually come up until you go into your BIOS setup, set things correctly (or just go in there), save and exit.

 

[ucla88]

the most common cause of this error is a failing battery. since the clock gets reset too, this is very likely the cause. if you get the error again after replacing the battery then flash the bios. offhand i don't know what battery it uses, but i'm sure if you go to abit's website you can find out.

 

[bozo1]

CMOS Checksum error simply is saying that your CMOS settings are invalid. The checksum error can be caused by many things - I would -not- suspect the battery unless it keeps happening. By pressing F1 (or whatever) to continue, the system is booting with default settings which is why the date is screwed up and the error occurs each time you boot. You need to go into your BIOS setup, set things appropriately, then save and exit. Only if the problem returns would I suspect a battery.

Things that can cause this error range from a BIOS upgrade (many systems wipe the CMOS settings when flashing the ROM), an electrical issue - card not seating well, certain mobo traces shorted while taking it out of a case or dropping a screw on the board, etc., and possibly a weak battery.

 

[oldfart]

Clear the cmos settings by shorting the jumper, then load defaults and see what happens.

 

[ucla88]

<< CMOS Checksum error simply is saying that your CMOS settings are invalid >>



well, not exactly. all it's saying is that the stored checksum in the cmos and the checksum calculated at boot are different.

every time one changes the bios settings, checksum is generated from all of the bytes and this number is stored.
when you boot, the computer recomputes the checksum and compares it to the stored value. while i agree all sorts of errors can cause this, it's very common for a dying battery to cause this.

if you don't belive me check this out



bios checksums

 

[ucla88]

oops, wrong page (interesting nonetheless)

linky

 

[MrBond]

Actually, no matter what I set the bios values to, upon each time the PC is turned on, I get the error. I'll try and get a replacement battery on my way home.