iPhone 6 back-light issue
A customer came with a iPhone 6 which has back-light issue. It looked the screen is dead but the Apple logo can be seen when use a flashlight to lighten the screen.
How to check the issue
From the circuit we know there are at least two group of parts are related to this issue. One is the flex cable connector J2019 and some inductance around. The other is chip U1501, L1501 and D1501. As circled in the picture as follows.
The easiest way to find the issue with J2019 and inductance is to measure the resistor value of J2019. These value can be found the value from ZXWtools. I measured and found pin 1 of J2019 is lower than normal. I also checked that all inductance are good, not burned. Then I found the diode D1501 is a bit burned from the appearance. First I replaced this diode, the phone is better. I can see the Apple logo when it’s powering on but it shut down itself very quickly. It seemed that some circuit is short. Then I replaced the chip U1501, finally it’s working fine.
Apple logo is back!
