# [resolved]CMOS Checksum Bad



## scottv (Nov 1, 2005)

I have recently installed a brand new, never used Asrock 939Dual-SATA2 motherboard I bought in 2005. I just put in a new AMD Athlon 64 3500+ 2.2 ghz processor.

Everything is set correctly. Processor and all drives are detected. Then I get a bad checksum error and the system is halted and I cannot select a boot menu or go into BIOS setup etc.

it says:

AMIBIOS(c) 2005 American Megatrends, Inc.
939Dual-SATA2 BIOS P1.20
CPU: AMD Athlon(tm)64 processor 3500+ (64bit supported)

Press F11 for boot menu
Dual-channel Memory mode
2048MB OK
Auto-Detecting Pri Master..(my IDE HD drive)
Auto-Detecting Sec Master..(My other HD drive)
and the rest of the drives info

Sec Master: my DVDRW drive

**************Warning: Unknown Processor**************
The processor(s) installed in your sysem are not known by the BIOS.
Please contact your BIOS vendor for appropiate updates.
Fatal Error... System Halted 0085



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The BIOS driver on the motherboard is version 1.20
I believe I need to update to at least 1.30 for the problem to be corrected but I cannot access the flash update since the system is halted. It does not work when I press F11 either since the system is halted shortly afterwards. (tried pressing f2 and alt+f2 and ctrl+home, but did not work, but I also did not have the floppy disk with the bios update in the drive either-still gotta go make one) I do not have an extra 939 cpu around to update the bios.


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## Aus_Karlos (Mar 10, 2007)

*Re: CMOS Checksum Bad*

Most M/B require you to reset the CMOS before use.. So locate the CMOS jumper and switch the pins from 1-2 to 2-3 for 5-10 seconds then put them back into 1-2 and start the system..
Hold down what ever button you need to enter BIOS and select "load default values"...
Look at your M/B manual to locate and how to reset the jumper if the jumper stuff ive explained looks different to yours...

Also check the M/B battery it maybe flat/faulty for unknown reasons..

Im not to sure about this step so hold off on this step until a tech guy answers this...

You may be able to get into your BIOS if you remove all components connected to it including processor.. With the exception of a keyboard, monitor and a Floppy drive.. But dont try this until a tech guy answers this question.....


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## mattlock (Dec 28, 2005)

*Re: CMOS Checksum Bad*

Hi Scott, You should be able to go into the Bios and Disable the "Halt ON" function. It'll say something like Halt On all errors. Change it to Halt on No errors. This should allow you to boot to the floppy and flash your Bios, and you're correct you do need version 1.3 to run that cpu.


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## scottv (Nov 1, 2005)

*Re: CMOS Checksum Bad*

Doh, I just couldn't wait :laugh: ....after my classes, I found a nearby computer store that had an older 939 processor handy and they plugged it in and updated my BIOS for a small fee. Everything is set now.

BUT....

I want to take your suggestions into consideration since this will be VERY useful information to me in the future so I won't have to go to a repair place and waste money for a simple task.

You guys are saying I can get into the BIOS and turn off the "halt on" function? *But would I have to remove the processor first and let the board run with just power and keyboard to do this? *(because if I have the processor on it would just halt during the POST:grin: )


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## dai (Jul 2, 2004)

*Re: CMOS Checksum Bad*

no you would need to put the older cpu in first to get into the bios,computer will not start with no cpu


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## scottv (Nov 1, 2005)

I see....well then...yeah I was pretty much screwed without an extra 939 processor then heh.


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