Chosen Solution
Hey there! Just got an Iphone 6s in the mail that I thought just had a backlight problem. I popped a spare LCD on to see if that was the issue. It still wasn’t displaying a picture. It was sold to me as “responding to touch” but just not showing a picture. I haven’t been able to hook it up to itunes, make any sort of noise or anything. It vibrates when I move the vibrate button up and down…that’s about it though. Any ideas?
Try shining a light onto the screen when you power it on(with a known working screen) and look for the Apple logo.
The backlight driver ic will need to be replaced. It will be shorting vcc main the main power rail
On the iPhone 6s its more often filter fl4211. It’s possible it could be a damaged driver from a possible short but I wouldn’t jump to the driver right away. Test resistance on the filter in ohms setting on the multimeter. You should be getting .5-.8 reading. If its high one like 42 or 100 or something your filter is bad. You have three backlight filters in this circuit. I would test all of them to make sure you’re getting proper resistance. If you are and still have no backlight examine the connector itself (this often goes overlooked) then move onto the two diodes then backlight driver ic.
