CMOS checksum error

  Bonzy 10:41 13 Dec 2004

Hello friends, I need your help here. A friend's AMD pc running Win98SE has run into a problem. When the pc has been on for quite a while, sometimes the monitor just goes off and moving the mouse or pressing a key does not wake it up. It happened last night and I tried to switch off the CPU but I noticed I had to keep my finger on the switch for a long time before it could switch off. Then I switched it back on again, but just after the drive detection bit it gave an error message saying:

CMOS checksum error - Defaults loaded.
Press F1 to continue.

I did that and it booted ok, but i dread the fault happening again. What exactly is happening and how do I correct this problem. Please help out. Thanks in advance.

  Graham ® 10:53 13 Dec 2004

The CMOS battery has failed.

  Gongoozler 10:55 13 Dec 2004

Having to press the power switch for several seconds to turn off is a safety precaution to prevent accidental switching off. This can be enabled or disabled via the BIOS setup. A CMOS checksum error indicates that the CMOS settings (BIOS controls) have become corrupted. This is most often the result of the CMOS battery running down. The battery is usually a CR2032, it looks like this click here and should be available at between £1.50 and £2.

  Graham ® 11:00 13 Dec 2004

click here for a guide.

  keith-236785 14:56 13 Dec 2004

to add to Gongoozler, the batter is available from pcworld @ £3.99/Staples @ about the same, or any local pc shop for about a pound or 2.

power off the pc, open the case, look for the batter on the motherboard. Using a small flat screwdriver VERY CAREFULLY flip the old battery out and push the new one back in.

fit the case back together and switch on, you will get the message again but dont worry, it should be the last time you see it.

dont forget to change the date and time once windows has loaded, then do a reboot so other software can start reporting the correct date (anti-virus/firewall which should show the computer to be at risk and need updating if the computer date is wrong) after the re-start you should be ok again

good luck

  pj123 15:13 13 Dec 2004

£3.99 for this battery from PC World! That's robbery. I can get this battery from my local electrical shop for £2.49

Check your local shops (even Boots sell it cheaper than that)

I must say that I have never, ever had to change a motherboard battery in any of my computers. In fact I have just dug out an old 486 DX40 with 8mb memory and 850mb hard disk and connected it up and the date and time are correct.

  Gongoozler 16:46 13 Dec 2004

As pj123 says, these batteries should last for years. The battery is only delivering power while the computer is not connected to the mains, either unplugged or switched off at the socket. Before changing the battery it's worth resetting the BIOS, either by moving the link to the "Reset" position, or by removing the battery for about 30 minutes. If neither of these nor changing the battery works then the problem is more serious and may possibly only be resolved with a new motherboard.

  Bonzy 08:12 22 Dec 2004

Thanx friends. I took out the CMOS battery, measured voltage , it was 3....V; I left it out for about 1hr and put in a new one I'd just bought. When I restarted the pc pc, the same message came up on the screen. Shd I take it that it is the motherboard that has to be replaced? Or should I leave it? becos pressing F1 on startup makes the pc fine to use. Thanx again.

  Fruit Bat /\0/\ 09:55 22 Dec 2004

Sounds like at 3v the old battery was ok.

Reset the Bios then reboot into windows. shut down and reboot again, with a good battery you should not get the CMOS error again.

If you do then the BIOS is corrupted but can be cured with a BIOS flash. Get the BIOS info Award / AMI and date as shown top corner of screen at first part of boot.

  Graham ® 10:04 22 Dec 2004

Sorry to hear that. In your first post you said the message 'defaults loaded' was displayed, so doing that manually may not be the answer.

Any new hardware been fitted recently?

And the monitor turning off is a puzzle. Perhaps a scan with A² click here

  Graham ® 10:07 22 Dec 2004

Emisoft not responding at the moment, try later.

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