Maintenance of Shenzhou Zhanshen z7 notebook no booting

Maintenance of Shenzhou Zhanshen z7 notebook no booting

no booting ble found on the b switch, b switch, b switch, b switch, b switch, b switch, b switch, b switch, b switch, b switch, b switch, b switch, b switch, b switch, b switch, b switch, b switch, b switch, b switch, BXT.

Machine model: Shenzhou Zhanshen z7 notebook

Fault phenomenon: notebook no booting
Maintenance process:
A z7 laptop of Shenzhou Zhanshen, the fault is the laptop no booting.When switch is powered on, there is no standby 3V. For example,Short circuit is available in the later stage.
Remove the machine, visually check that there is no trace of water damage corrode on the main board, and measure that the ground diode value of each large VCC is OK.The standby voltage is 3V and no 5V.Check the drawing data, found that there is 3V 5V in standby mode.
Al

Machine model: Shenzhou Zhanshen z7 notebook Figure 1

Disconnect 5V rear stage, pj32.

Machine model: Shenzhou Zhanshen z7 notebook Figure 2

Machine model: Shenzhou Zhanshen z7 notebook Figure 3

Start up 5V out, after the stage to ground diode value has more than 300 Europe, normal.Continue to trace, found that U21 8, 9 pin 0 euro.

Machine model: Shenzhou Zhanshen z7 notebook Figure 4

Machine model: Shenzhou Zhanshen z7 notebook Figure 5

On the Current heating test Dafa, quickly find the fault point.

Machine model: Shenzhou Zhanshen z7 notebook Figure 6

Machine model: Shenzhou Zhanshen z7 notebook Figure 7

After replacement, power on test,Normally booting up, troubleshooting, and maintenance are finished.