Lenovo Y470 Boot Dark Screen repair

Open Xinzhizhao software and find the Y470 point bitmap. First, find that the main power supply pins on the upper screen of the motherboard are 1 and 2 pins +LEDVDD, and the multimeter found a short circuit to the ground. Quickly find the components connected with it. After another test, one pin of C524 and R813 is in short circuit state, so replace it, and the resistance value of 1/2 pin of the motherboard screen interface returns to normal.

Machine model: Lenovo Y470

Fault phenomenon: the boot screen is dark

Maintenance process:

When I got the machine, the customer said it was a dark screen, and I saw that the starting current had been turned on normally. Change to the same good screen, and find that the fault phenomenon is the same, so the screen is out of order.

Lenovo Y470 Boot Dark Screen Maintenance Figure 1

Observe the screen interface and find nothing unusual. Usually, in addition to the failure of the screen logic board circuit and the previous LCD high-voltage bar, the dark screen is the screen line, and the main power supply of the screen on the motherboard is normal, which is the motherboard problem. Because there is no same screen cable at hand, we can only test the voltage of the screen interface of the motherboard first. The blind test is normal except for the main power supply.

Lenovo Y470 startup dark screen maintenance Figure 2

Lenovo Y470 Boot Dark Screen Maintenance Figure 3

Quickly find the components connected with it. After another test, one pin of C524 and R813 is in short circuit state, so replace it, and the resistance value of 1/2 pin of the motherboard screen interface returns to normal.