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CMOS issue & cure?

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October 11, 2009 4:58:00 PM

I installed over 20 pcs with MSI mobos some time back in a local school. After the Summer break of some 2 months many (probably about a dozen) refused to boot and access to the BIOS was not possible. I guessed it was a CMOS problem. Could that be due to the on/off switch on the PSU being left on for the holiday and causing battery drain? The power to the room was switched off.

I replaced batteries and still they did not boot. I removed the only ram chip and rebooted - a seemingly pointless exercise! Then replaced ram and in all cases the machines booted up fine straightoff. So this was a consistent cure for the CMOS problem.

So this post is really a piece of information that may help others. Not sure whether it is peculiar to that MSI mobo but its worth a try if you meet the problem.

My questions are: Why the battery drain? Is it due to PSU being left on? Can't think of any other reason.
Why then does removing the ram, booting and then replacing it work?
Hope this helps somebody and would be intrigued to know what was going on.
Thanks,
John B

More about : cmos issue cure

a b V Motherboard
October 11, 2009 8:50:19 PM

It's a mystery for me. Despite some printers and even computers saying to leave their "wall" power on, I still recommend turning everything off at the surge protector - if you're going to turn it off. If there's no power to the PSU, the soft on/off switch on the front has no function.

If these computer were set in BIOS to power on when power is interrupted, I could imagine some odd results. The maint people would constantly be turning the power on and off all summer and if systems were booting each time, plenty of chance of errors.

Did the computer show a CMOS reset? That is, BIOS settings that you put in place, like boot order or Smartdrive, etc, reset? If so, it would point to battery. But otherwise, the batteries should be able to last 3 yrs or much more, even if computer off the whole time.

And congrats on the nice sale. Hope you got some billable hours for fixing em, but when I was out there, I'd likely fix em for good customer relations.
October 11, 2009 9:52:47 PM

Never got to check BIOS as they wouldn't boot until ram removed. Then of course CMOS came up with anything it liked!
On one machine as soon as it booted into windows it was telling me it had just done a system restore to September 21st 2078!!! So yes the answer is it did show a CMOS reset of sorts.
Yes fixed then for nominal charge - didn't take long, 5-10 mins each when I got going. Taking case side on/off was most time consuming!
Actually wall power was off all summer in that room - only PSU on/off switch was left in on position. Not sure how that would drain the CMOS battery but its all I can think of. The fact that so many with same mobo should have CMOS problems (18 months approx from their build) points to some common cause - what ??? I don't really know.
John B
a b V Motherboard
October 12, 2009 12:25:27 AM

If you don't get any speculations now, might bump the thread up a couple times in a few days to get exposure - might be someone around that will recognize the problem.
!