CMOS checksum error

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What would be the cause of the following message when booting, BIOS startup halts and say:

CMOS checksum error – Default loaded

F1 to continue, Del to enter Setup.

OK for some weeks, I have had intermittent reboots, some day nothing, another day 5-6, followed by BSOD; Driver_irql_not_less_or_equal 0x..D1 (nv4_mini.sys) or no BSOD just reboot or IRQL_NOT_LESS_OR_EQUAL 0x..0A, then later same day rebooting and no way to turn off, left with blank screen then suddenly reboot and BSOD: Following file may… ACPI.sys, 0x…BE.

My only question in this thread is what causes a CMOS checksum error? I am trying to only put one issue, I may come back and ask for advices regarding the other problems, just mentioning them as some background.

Well, I went into Setup (press Delete) just to check what was changed. I could clearly see the default values, as I have done some minor changes over time (and I know very well what values are default, and what values was changed by the company who built the machine). So for instance the CPU HOST/SDRAM/PCI Clock was set to Default. When I bought the machine, and ever since, it has been 133/133/33. The Default value in my BIOS Setup (on my MB with AMD XP 1800+ (1533 MHz) ) results in only 1.15 GHz (100 not 133), thus the change.

OK, some other small changes were also made when BIOS Setup went back to default, but I know how to change them back.

After my check in BIOS Setup, with no changes made by me, the machine rebooted as I exited Setup, and I was again prompted to press F1 to continue or enter Setup. This time I chose F1 and the machine has been up and running since then, some 8 hours.

Regards,

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It could be a few things. Most likely, the CMOS battery needs to be replaced. Newer mainboards use button type batteries that you can find at most electronics stores. It’s a cheap fix.

If that doesn’t work, then you may have a jumper cap crossed that is clearing the CMOS, but this is highly unlikely sincer jumpers don’t change themselves.

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Mark: Hmmm, OK, this is a 14 month old machine, I don’t know how long these batteries last. If I remember correct from last time I looked at the mainboard; yes it seems to be a “button type” battery. I have another, ten year old, machine and have not changed battery on that one yet, maybe the old ones lasted longer?

Cowboy: OK, well I have not cleared CMOS, and not changed any settings in BIOS before the error. That is, I did some changes 50 days ago when I reinstalled XP. Small changes, disable onboard modem etc. and then some days later, changed CPU Core Volt from Default to 1.75 V (wich it should be for my Palomino) cause the MB undervolt slightly (Default gives 1.69 V). That’s all I can think of for the moment.

The checksum error came after some reboots yesterday, and I certainly do not know what went wrong this time.

I did flash the BIOS in April this year, and made a back up of old one. Everything worked well untill September when rebooting started.

Regards,

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Those little batteries usually last a few years, but perhaps you got a bum one this time. It’s also possible that this is a one time fluke, or an indication that you need to flash the BIOS with a more current revision.

If it doesn’t recur, I’d just cast a suspicious eye in the PC’s direction and perhaps utter a few choice words about technology. If it keeps happening, then it’s something to be concerned about.

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Yes, I would be very surprised if the battery was going already. OK , the error has not reappeared, first reboot since last night I went into BIOS Setup and changed to 133/133/33, (FSB), so I would get my 1533 Hz, saved and rebooted. Works fine, and today the boot also went OK. I have seen so many different error messages when in rebooting tango, and known that the actual cause is not always what is reported, so I am not all that surprised over this checksum error. Anyway Mark and Cowboy thanks for your quick replies and information.

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Yes, I would be very surprised if the battery was going already. OK , the error has not reappeared, first reboot since last night I went into BIOS Setup and changed to 133/133/33, (FSB), so I would get my 1533 Hz, saved and rebooted. Works fine, and today the boot also went OK. I have seen so many different error messages when in rebooting tango, and known that the actual cause is not always what is reported, so I am not all that surprised over this checksum error. Anyway Mark and Cowboy thanks for your quick replies and information.

Reply | Quote

Those little batteries usually last a few years, but perhaps you got a bum one this time. It’s also possible that this is a one time fluke, or an indication that you need to flash the BIOS with a more current revision.

If it doesn’t recur, I’d just cast a suspicious eye in the PC’s direction and perhaps utter a few choice words about technology. If it keeps happening, then it’s something to be concerned about.

Reply | Quote

Mark: Hmmm, OK, this is a 14 month old machine, I don’t know how long these batteries last. If I remember correct from last time I looked at the mainboard; yes it seems to be a “button type” battery. I have another, ten year old, machine and have not changed battery on that one yet, maybe the old ones lasted longer?

Cowboy: OK, well I have not cleared CMOS, and not changed any settings in BIOS before the error. That is, I did some changes 50 days ago when I reinstalled XP. Small changes, disable onboard modem etc. and then some days later, changed CPU Core Volt from Default to 1.75 V (wich it should be for my Palomino) cause the MB undervolt slightly (Default gives 1.69 V). That’s all I can think of for the moment.

The checksum error came after some reboots yesterday, and I certainly do not know what went wrong this time.

I did flash the BIOS in April this year, and made a back up of old one. Everything worked well untill September when rebooting started.

Regards,

Reply | Quote

It could be a few things. Most likely, the CMOS battery needs to be replaced. Newer mainboards use button type batteries that you can find at most electronics stores. It’s a cheap fix.

If that doesn’t work, then you may have a jumper cap crossed that is clearing the CMOS, but this is highly unlikely sincer jumpers don’t change themselves.

Reply | Quote