SOLVED: iPhone 6 Plus half screen is black and the other half is bright

A customer has sent us an iPhone 6 Plus to repair, which problem is the half iPhone touch screen is dark and the other half is bright, sometimes even no display.

 

Because the customer only sent us the iPhone motherboard, after we received it, we checked it immediately. We found the motherboard repaired, and the iPhone backlight has been replaced. By the way, there is a capacitor that is not installed.

Now we directly remove the yellow insulation tape, cleaning up the repaired place, and then supply power on it to test, the left backlight is dark.

After using the QUICK861DW rework station to weld the capacitor that didn't install before, turn it on and test it, now the backlight is back to normal, it can display normally. According to check the WUXINJI circuit diagram, we know that the backlight is a step-up capacitor, if none of this; it can't boost the voltage, so the backlight is not bright.

After fixing the backlight, we also need to repair the screen sometimes display but sometimes doesn't display issue. Sometimes it can display when you press the socket with your hand, so we thought it was a problem with the socket. However, after careful examination, we found that the socket has been replaced, and the pin also is fine, now we have to check its circuit.

After testing, we found that there is no display power supply -5.7V. As we know, -5.7V is directly output by the iPhone screen display IC, testing the line, it is normal. So we decided to replace the display IC directly. After the replacement, turn on the iPhone, now the iPhone screen works normally!