Dell CHARGER NOT RECOGNISED

Dell CHARGER NOT RECOGNIZED

Try this it could solve you problem

• Unplug power adapter and remove battery then hold power switch for 10 to 20 seconds

• Reset bios/cmos by removing cmos battery. 

• Set  bios/cmos to default setting.

• Try removing "Microsoft AC Adaptor" or similar from Device Manager, unplug charging connector, plug back in. (If your battery is dead, remove it then restart) 
• Check if the DC socket on your laptop appears slightly loose. If it has had any excessive force applied, it may have broken the solder connection to the motherboard. A repair shop (like me) will charge about £69.99p to repair it, as it involved stripping the laptop and taking out the motherboard. 

• Buy a NEW GENUINE charger from ebay of the right charger family. There are several types of Dell charger and if you don't use the right one, it won't recognise it, so some research may be necessary. A genuine charger should only cost about £20 or so, and will always have the Dell logo on it. 
• Alternatively, if the output wire next to the "brick" has an obvious kink or bulge, you could try repairing it But not recommended.

• The center pin tells the chip on the motherboard that you are using a genuine Dell charger, plus the charger's power rating (this is how a laptop knows you are using a 65W charger instead of the 90W charger), and even tells the laptop the serial number of the charger! Of course a standard multimeter will not read anything on the center pin because it's DATA, not a stable voltage! An oscilloscope is required to test it. 
• The low voltage cable is a concentric cable with a tiny white wire in the middle! I should know, I've repaired dozens of Dell chargers that no longer charge because this wire gets broken by people wrapping the cable too tightly around the block. If you open a charger up, you will see the three pin TO-92 case chip (looks like a typical transistor). This is the ID chip.