Laptop AC adapter doesn't work
If you are experiencing a problem where your laptop's AC adapter is not working or is not working correctly, there are several things you can check before looking to buy a new adapter.
Verify adapter plugged into a wall outlet
Make sure the AC adapter is firmly and securely plugged into the wall outlet. Although it may sound obvious, the adapter can become loose without even knowing. If it's plugged in partially, it can make it seem like the adapter is not working, but it may not be getting power from the wall outlet. When in doubt, a good way to make sure it is plugged in properly is to disconnect and then reconnect the connection.
Check adapter indicator light
Many laptop AC adapters have a power indicator light on the adapter brick. Check for this indicator light and if there is one, make sure it is light up with a green light. A power indicator indicates that the adapter is receiving power.
Check the wall outlet itself
Some wall outlets require a light switch to be in the on position for the outlet to be active. Many newer houses, apartments, and condos feature this type of wall outlet. If the light switch is on, verify the wall outlet is working in general. Use a voltmeter to measure the power output and verify the outlet is functioning properly. Alternatively, you can also try another wall outlet. Also, double check the circuit breaker and make sure nothing is tripped or turned off.
Check adapter brick connection
Most laptop AC adapters come in two pieces. Make sure both of those pieces are connected firmly and securely. The two pieces connect at the rectangular box piece, often called the brick. You can verify the connections by disconnecting and reconnecting all cables.
Adapter not plugged into the laptop
Although it may seem obvious, the adapter can become disconnected from a laptop pretty easily. The metal tip on the adapter cord needs to be firmly attached to the laptop for the laptop to receive power from the adapter. Also, in either the metal tip on the adapter or the connection on the laptop, there is often a small metal pin. Make sure this pin is not bent or broken as that can cause a problem with the laptop receiving power from the adapter.
Laptop power connection port
The power connector is connected directly to the laptop's motherboard, usually through one or more solder points. If a solder point is damaged or has broken away from the motherboard it prevent the laptop from getting power from the AC adapter. Fixing this requires very precise work with either soldering the power connector back onto the motherboard or replacing the power connector itself, if it is defective. In some cases, this kind of problem is not repairable and will require a replacement of the motherboard or power board.
If you think this may be your problem, it is best dealt with by technicians who may need to take apart the laptop to examine the hardware and diagnose the issue.
If you have determined the AC adapter is not working properly and needs to be replaced, you can get a replacement from the laptop manufacturer.
You can also opt to purchase a universal AC adapter from a local or online electronics retailer. One brand to look for is Targus, which is a quality brand and a popular choice. Targus makes several universal AC adapters which work for many laptop brands and models. Make sure you purchase one that matches the specs of your existing AC adapter, including the voltage and amperage. Also, check the packaging to make sure it will work for your laptop brand and model.