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Lenovo z485 notebook switch current 0.028 maintenance
Machine model: Lenovo z485 notebook
Board No.: dalz2cmb8e0
Lenovo z485 notebook switch current 0.028 maintenance Figure 1
Fault phenomenon: the current of notebook switch is 0.028
Lenovo z485 notebook switch current 0.028 maintenance Figure 2
Maintenance process:
Take apart the machine to measure all items of VCC without Short circuit, and measure the standby 3V and 5V normally. When measuring BIOS 8 pin and 3 pin, it is found that there is only 1.7V, which should be 3.3V normally.
Lenovo z485 notebook switch current 0.028 maintenance Figure 3
Lenovo z485 notebook switch current 0.028 maintenance Figure 4
Measurement found + 3V_S5 VCC is pulled down by 1.7V.According to the drawing pq142, 2, 3 pin,VCC are normal, pr432, pr437,diode value and VCC are normal, so it is judged that the problem is pq138.
Lenovo z485 notebook switch current 0.028 maintenance Figure 5
Lenovo z485 notebook switch current 0.028 maintenance Figure 6
Parts motherboard to remove a change, plug in, power on, the current easily run up.
Lenovo z485 notebook switch current 0.028 maintenance Figure 7
The screen lights up successfully and the repair is over.
Maintenance chart of switch notebook
