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How To Repair Voltage Absent In LA-7912P Motherboard

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Today lesson is about Acer Aspire V3-571G compal platform, it is one of the well-known model, LA-7912P, Rev; 2.0, in this platform, there are Bios, and water spilled problem.
First of all diagnose the platform:
1) it’s probably , been in other repair shop, because here removed pins are visible

2) What is the problem with this platform? It has start; power LED light and power button LED turn on

Amper is working between 0.09 and 0.10 amps, in this case, when Amper is working like this.

It caused by absent of voltage in CPU, chipset, and sometimes graphic card, Amper is low in this way.

Amper is 0.9; i will check the drossel too. In CPU, GPU, and chipset have not voltage, there is no voltage, in drossel also. The voltage is in Rom and in stand by voltage and here is 0.9v in drossel.But in CPU, GPU, HM chipset have not voltage.
acer-article-pic3.png

Here, +VSBP signal is important signal on the motherboard, on absent of this signal, there won’t be voltage on other parts, I cleaned the oxide part, on P-channel MOSFET, in its second pin. There was rusty, I cleaned and make it alright. This time Amper works, I start it and, Amper is 0.27, fan is also spinning, laptop turns on. I check it again, and then laptop turns on and off.

If you look carefully to this part, from motherboard main line 19v enters, here is a point, which is soldered point. And here because of its oxide, it’s not working. See this point, under the microscope.
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Because this is basic 19v voltage part is here. And on +VSBP, stand by power signal is active. Signal goes to this part but here is disconnection so signal stops. So I established stand by power signal, I connected a wire. Before connecting the LED for final work, i check it with postcard, it display 00 codes. Motherboard is working in normal way.
acer-article-pic.png

Amper is after connecting the LED, changes to 1.13 amps.
For better understanding, we have provided bellow video!
Enjoy!
 

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