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April 19th, 2025 21:01
XPS 8940, no boot, CMOS battery?
My Dell PC will not boot. I have three amber lights and one white light flashing. I believe that means that the CMOS battery needs to be replaced, but I would like someone to verify that if possible.
I ran the Dell system diagnostics that automatically start after multiple boot fails and the reports came back as pass for all system devices. No hardware or software issues were reported.
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ispalten
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2.3K Posts
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April 19th, 2025 22:12
Yes, you can do it easily.
See https://www.dell.com/support/manuals/en-us/xps-8940-desktop/xps-8940-service-manual/installing-the-coin-cell-battery?guid=guid-adfd205b-4de3-427a-8830-4d59cbd1cb95&lang=en-us
Odd that you could run the diagnostics? I say that because the usual problem with a dying battery is loss of BIOS settings, and that could mean identifying the h/w connected?
Give it a try, but once done, go into the BIOS and verify all settings are correct.
Lorac2046
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April 22nd, 2025 06:33
Once I replaced the coin battery in my Dell it began functioning properly again. All of my settings were restored without intervention. The time was right, the date was right. All my programs were working properly. It was as nothing had happened prior to the battery going out. I consider myself quite lucky that I didn’t have to go into the bios and make a lot of changes.
The diagnostic that ran is a program installed on Dell computers that is sort of hidden, and that doesn’t activate until several faulty restarts take place. I had no idea that diagnostic was on the computer until I went online and started reading and found an article that talked about it. Thank goodness Dell provides that feature because once I ran it, I realize hardware and software were not an issue and so it had to be that dang little coin battery.
Thank you for your help in replying to me. I felt like I needed someone to hold my hand while I made the decision to replace that battery. After all, I am an old lady with some knowledge of computers and the web, but not enough to solve huge problems.
Carol
Muppets_Waldorf
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June 5th, 2025 21:06
Most stuff does work fine without a battery, as long as it has power coming in from the outlet, but its always a good idea to replace those (even if its jsut for testing) if its older than 3-5y.
GuillaumeCdB
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July 4th, 2025 10:13
My Dell XPS8940 is from January 2021 and I already had to replace the CMOS battery twice, that is about every 2 years.
I have a Dell XPS8000 from 2009 and I think I have replaced the CMOS battery maybe once.
Somehow, when the XPS8940 is disconnected from the mains, the CMOS circuitry seems to demand a lot of power from the CR2032.
Also, it is bizarre that when de CMOS battery has "died" the Dell screen with "Diagnose" appears. One can ignore it and click on "Continue" and after a while the computer will boot "normally".
Willy