ac adapter turns off when battery is inserted

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ac adapter turns off when battery is inserted

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Hi,

I have a Dell XPS m140 when I use the ac adapter without the battery inserted the laptop powers up fine. When I insert the battery and the ac adapter the adapter turns off after a few seconds. If I unplug the ac adapter and do it again the same thing occurs. When I remove the battery and use the ac adapter after I unplug it from the wall the laptop will power up again. I don't know if the ac adapter is not  strong enough to charge the battery and boot up. I tried just having the battery in and not turning on the laptop to see if the battery would charge and the ac adapter turns off after a few moments. Can a battery have a short in it to cause this or is the adapter finally going south? I tested the adapter and it shows 19.5v. when the adapter light goes off it tests 0. After I unplug it and replug it,  it shows 19.5v again.I don't know where to go from here, new battery or new adapter.

Thanks,

John

Verified Answer
  • Hi Hank,

    After running a meter on the motherboard at several different areas, it was found to have a short between the power jack and the charging hardware. I replaced the motherboard off ebay new in a box for about $90. It took about 45min to install and close shop. Thanks for the response.

    John

All Replies
  • it doesn't sound like it's the adapter. they're designed to shut off like that when they detect a charging problem. If the test button on the battery gives you the error code when you press it  then get a new battery. If it doesn't then i don't know because it could be a system board issue as well. the only way to know for sure would be to try another battery.

     

  • I have the EXACT same problem with the same laptop.  It is not the battery (a brand new dell battery does the same thing).  If you take apart the laptop and remove the motherboard, you can then boot up from the battery.  As soon as you plug the power supply in, the same problem comes back (I have a brand new dell power supply, so it is not the either).  I think the internal charging protection circuitry on the motherboard is stopping the charging for some reason.  I am continuing to troubleshoot...

  • Flashing the BIOS didn't help...

  • Hi,

    I didn't see a bios update for this laptop.

    John

  • I reflashed A04 from a CD.  I had to do this from DOS since the windows command prompt won't let you do this without battery.

    Continuing to troubleshoot and frusterated...

  • I know this is an old post but my M140 is having the same problem. Just wanted know if anyone had figured out the problem.

  • Hi Hank,

    After running a meter on the motherboard at several different areas, it was found to have a short between the power jack and the charging hardware. I replaced the motherboard off ebay new in a box for about $90. It took about 45min to install and close shop. Thanks for the response.

    John