Troubleshooting Laptop Power Failures - The AC Adapter
Wiggling the AC adapter cord causes the power status LED on the laptop to blink.
Diagnosis & Solution:
The problem could be that the copper wires inside the AC adapter cord became frayed or broken right where they enter the connector on the end of the AC adapter cord. The wires (a number of very thin conductors twisted into a heavier cable) are sized for the amount of power the laptop requires. As thin wires break and lose contact, all of the power must flow through the remaining conductors, leading to overheating, which can cause damage or be a safety hazard.
To make sure that this is the case, first test the output voltage from the connector on the end of the AC adapter cord using a digital multimeter set to measure DC voltage. While measuring, bend the AC adapter cord in various directions. If this causes the reading to jump betwwen zero & the nominal output voltage (written on the label on the AC adapter), then you know that you will need to replace the connector.
In order to get this fixed, you will need a new connector and basic soldering skills, or you can take it to an electronics shop for a cheap repair but get the price before agreeing. If you decide to repair it yourself, then you will have to find a replacement connector. Most of these connectors are easy to find and your local Radio Shack often has them in stock. Just bring your laptop along to make sure you get the right size. However, some laptops use a highly proprietary connector for which you can't easily find a replacement, in which case your best option is to find a failed AC adapter for your laptop model, cut the end off (with plenty of slack) and splice it onto your AC adapter's cable.
If you work on irregular surfaces (like a lap) and allow the cord to dangle, the wires may break just inside the connector due to pulling, despite the fact that the factory connector is encapsulated in molded plastic. You can carefully take apart the molded plastic with a razor knife to temporarily fix a connection, but it's smarter to replace the connector end as soon as you determine it is causing intermittent power failures.
Another possibility might be that the power receptacle in the laptop (where you plug the AC adapter cord) has failed. Sometimes the center pin of the connector breaks off, sometimes the solder joints on the main board fail, sometimes there's a break between the connector contacts and the motherboard contacts. In all these instances, you or the technician has to gain clear access to the laptop's motherboard to make the repair. In order to get this done, you might need clear disassembly instructions, as well as decent soldering skills. You could get a replacement connector usually for less than $10, but the repair charge can be several hundred dollars for some models if you take it to a local shop.
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on Oct 13, 2010 | Computers & Internet