Is it the DC Power Jack or the Power supply?
First of all we have to find out if it is actually the DC Power Jack that is faulty, normal symptoms are:
- Battery not charging
- No power light
- Battery starts to charge if power cable moved to a specific position, and it begins to get harder and harder to get the power cable in a position where the battery charges over time
To determine if the problem is the power jack simply get a multi meter and test the plug coming from the power supply for a voltage, also try to waggle the cable as sometimes the cable can have an internal break, if the cable has a break or there is no voltage coming from the supply then the power supply needs to be replaced, if there is a voltage, then the problem is inside the laptop and is most probably the DC Power Jack.
To replace the Dc Power Jack, you need to remove the motherboard from the laptop, de-solder the old jack and re-solder on the new one. Care must be taken when doing so as the motherboard is easily damaged, and if any extra damage (i.e. cracking the board or damaging the tracking) is made whilst attempting the repair then the laptop will be only good for spare parts as the motherboard costs approx £200 - £400.