Lenovo Xinchao 7000-13 laptop no booting maintenance

Machine model: Lenovo xiaoxinchao 7000-13 notebook

Fault phenomenon: notebook no booting

Maintenance process:

Lenovo Xinchao 7000-13, plug-in adjustable power on no power on, no standby.Remove the back cover, unplug the COMS battery and power on again later. The fault is still the same.
After measuring the whole motherboard Inductor, there was no obvious Short circuit. After power on measurement, it was found that there was no 3v5v. After looking for the drawing, it was found that the Current protection isolation tube of this machine was n-tube. The physical measurement was found on the board.

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Lenovo Xinchao 7000-13 laptop no booting maintenance Figure 1

Follow Boardview.

Lenovo Xinchao 7000-13 laptop no booting maintenance Figure 2

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Lenovo Xinchao 7000-13 laptop no booting maintenance Figure 3

Find out that the physical measurement is normal, and the first MOSFET is not completely connected. Check which chip controls the G pole of the isolated Current protection tube.Continue to track down the charging chip 1 pin, there is no VCC, measuring resistance Diode value is normal,Capacitor is normal, diode is wrong, positive and negative are 580.

Lenovo Xinchao 7000-13 laptop no booting maintenance Figure 4

Replace d5901, the plug-in current is out, but DC power supply, the current lamp flashes or short.

Lenovo’s new maintenance notebook no booting

After Measuring diode value, it was found that the whole board Inductor was still normal without obvious Short circuit.On the forum to learn experience, some people say it is the screen interface Short circuit.