I am the recipient of a Dell Inspiron 6400 which I received with a dead battery although the ac adaptor would power the unit. I obtained a new battery for it and installed it thinking my problems would be over, but sadly I'm getting the AC-Adaptor = Unknown Device Installed with BIOS version A14. I've reviewed this. But my question is does anyone know of a version of the BIOS that will ignore the blocking circuit and allow the battery to charge? I don't really want to throw more money at this old laptop buying an AC adaptor when the problem may be at board level. but I hate to pitch it because otherwise it works fine.

  • Are you using a dell power adapter or some other brand?
    – DavidPostill
    Sep 8, 2016 at 16:43
  • It's a MayDay Tech 65W-DL04 providing 19.5V @ 3.34 amps
    – Elder Geek
    Sep 8, 2016 at 18:08
  • @DavidPostill I understand that the blocking circuit is there. What I'm wondering is if there is a BIOS version that fails to check it or fakes the signal. I'm willing to roll back to a previous BIOS if it will allow the battery to charge (granted not best practices but this system isn't critical and isn't worth much)
    – Elder Geek
    Sep 8, 2016 at 19:41


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