Problem: This laptop came with a complaint, no power.
Laptop Brand: Sharp
Model: PC-MJ720R
Diagnosis, cause and solution: The first thing I did was to test the adapter with a multimeter to check if the adapter is causing the problem not the power or not. The supply voltage is displayed on the 19V power adapter, when I tested the voltage normally. Since the adapter is good enough, ourconcentration 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 Guilt, and yet there is a difference. If I go to the backup test, I found that the backup was also opened, the rate of 5.5 amp fuse and if further testing, I found a shorted diode.
The reason that the terminals were short-socket, as the diode is connected to the output short-circuit short-circuited. Replacing the diode and securing the laptop come to life. Hopefully this article helped to get power to ideas on solving any problems portable.
Haveyou find those tips above helpful? If you did, you can visit the following website to learn a lot more: http://www.Compunics.blogspot.com/2010/06/podnutz-high-definition-laptop-repair.html - This website contains repair guides, tips, tutorials, and other information which you can use to fix your own laptop or notebook. Also, you can even use it to fix other people's laptop or notebook which is very good if you're planning to build your own computer repair business.
Friends Link : Sony VAIO VPC-EB15FM/T
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