Check all connections from the wall outlet to the charging port at the back of the laptop. There is a way to see if the plug part of the power cord is defective but it involves using a multimeter/voltmeter. Is there a warranty on the AC adapter?
If you ordered a cheap replacementoff like ebay then go ahead and try another one. The hassle you'll get trying to exchange this one isn't worth it. Its better to pay $20 bucks with $3 shipping for the psu as the $3 ones with $20 shipping dont care if they send you a good one or not. I literally got one that rattled in the envelope and they still wouldn't just send me another one free.. Had to pay shipping plus send the broken one back.
If the wattage is too low, the Dells sometimes refuse to charge. You will see the charge light blink instead of staying a steady color. If I use a standard 90 watt unit on my m6400, which uses a 250 watt brick, it will work only now and then. Sometimes it blinks, other times it will charge and the laptop gives me a warning that the unit isn't charging properly and I need the proper one. Make sure the output matches the rating of the old unit.
I bet you bought a very cheap adapter. Obviously your adapter output current and voltage is quite not stable. You should change it for a new one. Poor adapter will damage your laptop. My adapter is also a replace, named RAVPower. But it works fine. Suggest you try this.
its not your charger, its the operating system. this is a problem with dell and windows 7, if you google it youll see the issue is very common. i had this problem and bought a $2 charger on amazon. that charger actually works fine, but the laptop only charges when booting off of a live fedora disk. the issue has to do with power managment systems in the windows 7 OS and its interaction with dell bios. for some reason these dont always get along. again this is a software issue NOT a charger or battery issue.
* Check for the battery, functionality and status in BIOS(Start your computer and start tapping F2.
* Check for the AC Adapter, functionality and status in BIOS.
* Check whether the battery Status is Enabled in Control Panel under Power Options.
* Check the Dell Battery Meter (will be available only if Quickset is installed) or just check the battery status in Control Panel under Power Options.
* Install / update Dell Quickset and flash the BIOS from support.dell.com (Minimum Req. : Battery Charged > 10% and Functional AC Adapter).
* Even after flashing BIOS if you still get the same error message please let us know.
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