The Apple iPhone 5s was announced on September 10, 2013. Repair of this device is similar to the previous models, and requires screwdrivers and prying tools. Available as GSM or CDMA / 16, 32, or 64 GB / Silver, Gold, and Space Gray.

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iPhone 5S no display but backlight

Hello,

Happy to send my first message on this forum! :)

So my request is about an iPhone 5S.

He start completely but nothing are display and the backlight still works.

L19 coil has a little water damage, the pin 1 of L19 probably short to the gnd through the metal plate.

But he seems no dead, how can I test it properly?

And are there any other parts to test in this area of the logicboard known for display issues?

Can this coil cause that or it's more like a death of the U3 LCD controller chip ?

Help me understand please..

Thanks in advance!

Answered! View the answer I have this problem too

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So after peeling iPhone 5S diagrams, I just check the power input and I find the standart value : 1,8V / 6V / +5.7V / -5.7V

Does it always point to U3?

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I am concerned about your comment "has a little water damage". Water damage can be very insidious. Although you may see just a bit, there can be extensive water damage under the shields, under the IC's etc. Sometimes the repair is straightforward, other times it can require extensive troubleshooting. The best thing to do first is a complete decontamination, then troubleshoot.

Are you an experienced tech looking for detailed help or an avid DIY'er looking for guidance? If the latter, then look for an experienced shop specializing in micro-soldering and water damage repair.

Update (11/22/2016)

Generally speaking, coils such as L19 rarely go bad. They are, by design, a short circuit. That said, some corrosion may have eaten through the wire and made it an open-circuit but that should be easy enough to check. You can remove L19 to check it properly. Also check the bare pads to see if they are not shorted to ground.

L19 connects from PP_VCC_MAIN to Chestnut. What voltage do you read there?

If everything looks okay, including the coil, I would try to replace chestnut.

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Thanks to answer!

Yes I know the ravages that can cause oxydation..! But in this case, the emi shield showed signs of water in a restrained area of the board, precisely on L19 coil.

And yes I forgot to specify that the phone was properly cleaned in isopropyl alcohol (without emi shield) before anything.

I'm refurbishment tech but I would learn the hardware troubleshooting. I have knowledge in micro soldering and electronic.

So I believe I'm looking for tech who have encountered this kind of problem.

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Arthur Trouillot will be eternally grateful.
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