Why Huawei Honor 8s does not react to the power button

Recently Honor 8s came to us for repair. The problem was described by the owner as - does not turn on and does not respond to the power button. When charging, the screen shows the charge indication - charged to 100% and it is logical that the phone should be turned on. The client tried to repair the phone himself and independently ordered the cable of the buttons and replaced it, but the phone did not turn on.

It was always important for us to understand the quality and accuracy of the repair. So, we disassembled the phone, connected our new cable for the buttons. But the phone still didn't turn on.

Then we decided to test the contacts to the power button with a multimeter. Analyzing the testing results, we were convinced that there is no resistance on the line, which means a break in the contacts and we need to find out in what place.

To do this, we took the identical printed circuit board from our scrap bin and started to look for the tracks where the signal passes through. The track of the power button was found under the metal screen, next to the cable connector.

After removing the cover from the repaired device, we found that in the absence of visible signs of getting liquid into the phone, it was under this cover - the liquid got under it, resulting in damage to electronic components.

After cleaning it became clear that one of the resistors had rotted off on one side and the signal from the power button simply could not pass.

To repair it is necessary to prepare a contact pad area for mounting / soldering of components.

We put a new or working resistor in place and thereby restore contact.

After reassembly the phone turned on, which means that the repair was successful.