What would cause this computer fault?

A computer I have 'forgets' its BIOS settings when turned off at the wall. The error messages when booting mention the Real Time Clock, checksum invalid, and onboard battery may need replacing.

I've tried three different (new) batteries, but the problem persists. I've checked their voltages with a multi-meter, and all show the correct 3V.

I've also checked for dirt, corrosion, contact alignment, etc, with the battery holder.

Is this more likely to be a motherboard fault?

geek_-bookzone-, Aug 1, 9:58 am

More likely damaged CMOS RAM, I'm guessing.

geek_r.g.nixon, Aug 1, 10:03 am



Which isn't something easily replaced, I'm guessing - without being uneconomical with an older computer?

geek_-bookzone-, Aug 1, 10:08 am

You might be able to flash the BIOS if the error was corrupt CMOS ROM, perhaps itself caused by incomplete/incorrect flashing in the past. There'd be some risk of completely bricking it though. If it's a desktop, then a replacement used m/b, with or without CPU, RAM etc might not be expensive and/or an opportunity to upgrade.

geek_mm12345, Aug 1, 10:25 am



It's not worth replacing the motherboard really, but thanks for the input.

Is there likely to be any other 'easy' fix for this type of problem, or is it most likely 'terminal'?

geek_-bookzone-, Aug 1, 10:40 am

just scrapped a whole lot of boards with that issue
re-flashing the bios doesnt always solve the issue - assuming you're actually able to in the first place, - thats basically the only job you still need a floppy disk/drive for

geek_pcmaster, Aug 1, 10:45 am



So, what actually causes this? Just old age?

geek_-bookzone-, Aug 1, 10:50 am

There's a jumper on the board to clear the bios memory, if there's a chance the jumpers have been changed then look to make sure the 'Clear Bios' jumper is not in the on position. Another possibility is that the standoffs that hold the board away from the case are loose and shorting out some pin. After that I'd suspect a failed capacitor. Can you leave the computer always turned on at the wall?

geek_gyrogearloose, Aug 1, 11:41 am



Can't see a jumper like you suggest, a three pin type in the wrong position, this motherboard only seems to have a two pin jumper, as indicated in this image of the same type of board. The CMOS reset button is also circled:

http://iforce.co.nz/i/ichkztnl.dmc.jpg

As for leaving the computer on all the time, that's not an option.

geek_-bookzone-, Aug 1, 12:56 pm

Just have SPTimeSync run on startup to get the date and time automatically.
http://forums.scotsnewsletter.com/index.php?showtopic=19415

geek_r.g.nixon, Apr 14, 10:25 pm

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