What does the AC do? (Alternating Current)
Apparently not get rectified into DC electricity by the AC adapter, (Charger), or the rectified AC (Which is now DC), is not getting to the laptop.
Be sure the Battery is still good. They have a lifespan, and only last so long.
Verify, by performing a DC Voltage test with a multimeter, if the AC adapter is putting out the correct Voltage.
If it is an AC adapter for an HP Compaq NC6400 Notebook PC, the DC Voltage coming out of the AC adapter is supposed to be
18.5 Volts. (DC),http://www.amazon.com/Notebook-Adapter-Presario-cq50-142us-cq50-110/dp/B001MQ4MNW
On the AC adapter plug going to the laptop, the center pin is the Positive connection.
The outer cylindrical metal shell is the Negative connection.
AC adapter puts out 18.5 Volts?
Have an assistant;
1) Gently wiggle the power cord coming TO the AC adapter.
2) Gently wiggle the cable coming FROM the AC adapter TO the laptop.
See if you get an intermittent reading on the multimeter. Indicates a broken wire.
[ An economical, but fine for this test, multimeter, can be purchased for as little as $8 to $12, here in the US.
Analog or digital is fine.
Available in a multitude of stores. An auto parts store is but one example ]
AC adapter checks out it's on to the DC Power Jack.
This jack is the round port on the laptop, that the plug from the AC adapter plugs into.
Battery removed use a wooden small object, and gently see if you can move the center pin around, for the DC Power Jack.
See if the rest of the DC Power Jack will move around.
ANY perceptible movement means a problem with the DC Power Jack.
The DC Power Jack looks like this not mounted to the motherboard,http://www.batterystyle.com/compaq-nc6400-jack-p-436629.html
Click on the two views shown of the DC Power Jack.
The view on the left shows the jack from the back.
The view on the right shows the jack from the front. The view you see now.
Note that in both views the jack is shown upside down, in relation to how it actually sits on the motherboard.
The view on the left, (Back view), shows Prongs coming from the jack, that go down through the motherboard, and are then soldered.
The gold colored prong is the Positive prong. It goes to the Center Pin of the jack.
All of the silvery colored Prongs are for Ground, or Negative.
Where the Prongs are soldered to the motherboard, are called solder joints. Each prong has a solder joint.
It may just be that one, or more solder joints are cracked.
This would require disassembling the laptop down to the bare motherboard in your hand, then re -soldering any cracked solder joints.
[ Be SURE to use an ESD wrist strap, and have it's alligator clip connected to a good ground source, BEFORE working inside a laptop ]
It may be however that the DC Power Jack is damaged, and replacement is necessary.
HP Support > HP Compaq NC6400 Notebook PC > Manuals page,http://h20000.www2.hp.com/bizsupport/TechSupport/DocumentIndex.jsp?contentType=SupportManual&lang=en&cc=us&docIndexId=64179&taskId=101&prodTypeId=321957&prodSeriesId=1847703
On this page click on - Service and maintenance information
(Under the - Quick jump to manuals by category - heading)
Under the bold - Service and maintenance information - heading, click on -
HP Compaq NC6400 Notebook PC Maintenance and Service Guide
(24 Apr 2007 / 4.61MB )
[ This is a PDF file. The computer you are using now has Adobe Reader on it, which uses PDF files.
After you click on the above file name, it may take up to 30 seconds, before the first page comes up ]
Need guidance in de-soldering, and removing the old DC Power Jack, and soldering in a new one?
Post in a Comment.
If the DC Power Jack checks out, you have a bad power correcting chipset. This is a type of Power MOSFET.
Motherboard replacement is the solution.