Do you have the experience that your battery charges only when your laptop is off. When your laptop is on, the battery stops charging even the adapter is still plugged in. Do you want to know why?
That would be my first thought that the battery may be bad. You can use a battery with good quality to have a test. If the symptom disappears, that would be battery problem, you can replace it with a new one.
If this can not solve the problem, you may check the AC power adapter itself. The AC adapter doesn’t provide enough power when it plugs into the laptop. In this case, you should take a suitable AC adapter to have a test. How can you know the AC adapter is suitable or not? First, the output voltage MUST be exactly the same. If your laptop requires 19V, you must use 19V adapter. Second, the amperage should be the same or higher. If the laptop requires 6.3amps adapter, you’ll have to find an adapter which provides 6.3amps or more. Only in this way, your laptop can be provided enough power. Use the newer adapter can fix the problem, you just have to repalce the adapter.
Of course, the power jack may affect it too. The power jack may don’t connect very well with the motherboard. What you need to do is disassembling the laptop and remove the motherboard so as to see if there is a good connection between the power jack and the motherboard. Reconnecting it or replace the power jack. In other circumstances, the motherboard may be bad.
If you have this problem next time, you may have a try.