Diagnosis, Cause and Remedy: The first thing I did was testing the power adaptor with a multimeter in order to verify whether the power adaptor is the one that’s causing the no power problem or not.
The supply voltage indicated on the power adaptor is 19v, when I tested it, the supply voltage is just normal. Since the power adaptor is just okay, our concentration now is on the laptop itself. In order to ascertain whether the motherboard of the laptop or other peripheral devices which is connected to the laptop causes the no power problem, we have to disassemble the laptop piece by piece.
After unscrewing all the laptop parts, I individually pull out each peripheral devices. After completely taking out all devices which is connected to the laptop. I now separated the motherboard in order to be tested. But first I clean out all the dust from the motherboard for this is also a one factor which causes the motherboard electronic components to be shorted. Because when dust gets thick it will become a conductor.
So you need to be aware of this, every time you disassemble a laptop motherboard you need to free the motherboard from all dust, to be sure not the dust is the element causing the motherboard’s electronic component parts to be shorted. After cleaning all the dust from the motherboard, I scan all the components to see whether there are any dry joints or not. Dry joints means loose or poor solder connections. Poor solder connections on a laptop motherboard usually occur when your laptop is already well-advanced in years. I did not find any poor solder connections on any part of the motherboard, but for contentment I just carefully resoldered all the SMD components especially on the power section.
Note: All laptop nowadays is designed on a Surface Mounted Device or SMD mode, and this is rarely have dry joints. But for satisfaction I cautiously resoldered all the SMD components particularly the SMD components near the dc power jack.
After resoldering all the sections that needs to be resoldered, I inserted the dc power plug adaptor to the dc power jack and see whether the power comes up. Unfortunately, the condition of the problem remains the same. I now tested all the electronic parts on the motherboard to find out whether there are any shorted electronic element parts which causes the no power problem. After testing all the components that could be tested merely with a multimeter, I could not find any shorted parts. The only parts that I still not checked was the dc power jack and the fuse.
The final step that I did was testing power jack from input to ground for short. When I tested it, voila! the problem found because it is really shorted. I used x1 range of my multimeter to see the fault and either way there’s a deflection. When I go on testing the fuse, I found that the fuse was also open, the rate of the fuse is 5.5 amperes and upon further inspection I found a shorted diode.
The reason why the power jack terminals were shorted is because of the shorted diode that is connected to the power jack. Replacing the diode and the fuse brings the laptop to life. Hope this article helped you get some ideas about solving laptop no power problem.