Lenovo B460 notebook Won't Turn On repair

Lenovo B460 notebook Won’t Turn On repair

Lenovo B460 notebook Won’t Turn On, replace the damaged components after the fault repair.

Machine model: Lenovo B460

Plate No.: la46 dis 09911_1M

Fault phenomenon: notebook Won’t Turn On

Maintenance process: there is 0.028a when powered on (I have a little problem with the adjustment. If I don’t operate the computer, there will be 0.024a display. All the real ones should be only 0.004a).Switch.4501.

Lenovo B460 notebook Won’t Turn On repair Figure 1.

Lenovo B460 notebook Won’t Turn On repair Figure 2.

After dismantling the machine, it was found that there were signs of blackening and burning in the lower left corner.

Lenovo B460 notebook Won’t Turn On repair Figure 3.

pin e uxt01 chip is burned down, the other chip which is not connected with the other chip is burned down.

Lenovo B460 Notebook Won’t Turn On repair Figure 4.

Scratch it a little bit to lay the ground value, and judge that the right side is GND. I wonder if the chip is broken when it is burned like this? All pin’ s have ground values, which are basically normal. If there is no Short circuit’ s, please make up the bad ones first. However, this 100K resistor is easy to find, but the 249K resistor is hard to find, so I turned over the waste board, and a surprise appeared.

Lenovo B460 Notebook Won’t Turn On repair Figure 5.

The same board, except for the standby chip, is still around. By checking the position, it proves that my initial judgment is correct.

Lenovo B460 Notebook Won’t Turn On repair Figure 6.

This is what it looks like after being changed.

Lenovo B460 Notebook Won’t Turn On repair Figure 7.

All Inductor pairs have been hit all over the ground, so they are powered on and tested. They happily run to 1.4A, and the screen is directly displayed, and the maintenance is finished.