My Laptop won't Power up with the AC

[techinaspot]

My laptop is Dell Latitude D531.
For some reason my laptop just did not startup with the AC adapter in it.
You'd see the battery light symbol and the power symbol come on, but the monitor
would stay powered off.
When me and my friend pull out the adapter and powered up the laptop it run normally.
Even plugged back in the adapter and the charged laptop charged normally, and it would repeat this process.
Could it just be a faulty AC adapter or is it the battery?
Thanks in advance for your help.:wave:

 

[fastco]

I would say that it is a faulty AC adapter but have it tested to be sure before buying a new one.