NFC Troubleshooting

Welcome back to the repair blog!

Today we’re looking at iPhone NFC faults and how we here at Gadget Recycling troubleshoot them.

What is NFC?

NFC stands for near field communication which is a low range wireless technology that has been around in iPhones since the launch of the iPhone 6 back in 2014. In the Apple ecosystem NFC is the fundamental component that enables Tim Cook’s vision of contactless payment, Apple Pay. We consider this component to be one of the most overlooked aspects of repair since there isn’t a direct tool built into iOS to check it.

Apple Play Logo

We don’t believe NFC is worth forgetting about however. In fact, with the changes over the last year, contactless payment is more popular than ever. As you can probably imagine a situation where the service fails to work is a rather embarrassing one to be in. Not the experience we want our customers to have and something that isn’t easily forgotten, ask me how I know…

Anyway traumatic memories of scrambling for debit cards aside, the question remains – how does one test and correct NFC? As mentioned iOS doesn’t have a built in system so you’ll have to resort to third party software. For those starting out we recommend NFC Tools on the App store, it’s free and gets the job done. If you’re scaled up then something like BlackBelt 360 or PhoneCheck should have you covered.

We use NFC coil stickers for the software tests and an NFC pulse testing card for troubleshooting.

NFC Test Coil Sticker

Time to troubleshoot

In our experiment we used an iPhone 7, however, the core principles are the same on newer models. Generally, we’ve broken down the problem into 3 categories (of which 2 cover the overwhelming majority of cases for us):

  • Contact Shorts
  • Connection issues with loop
  • UXP Chip faults

We won’t cover the latter here as that’s a discussion for another day, involving SMD Board repair which is it’s own topic.

System overview

When it’s working correctly the system works as a loop; there is an antenna pad on the top right of the board, which is the starting point; and a flex wire that connects through a standoff screw pressing down on the pad. This flex wire then runs up alongside the rear camera assembly and into the top part of the chassis. This then carries across to the left side of a device through a screw embedded into the platform that the display sits into. The wire continues into another link that is screwed into the board where it’s forced to contact an auxiliary ground, completing the connection.

Connection issues

For Connection issues with the loop, every link in the chain is a suspect. We find it’s best to approach this in the same path that the NFC takes – right to left. So make sure there is no display adhesive sitting in-betwen the connections or missing screws, and that the following is tight*:

*note this applies specifically to iPhone 7 and 8 series, other models may differ

  1. The standoff screw into the board
  2. The screw from the flex shared by the standoff into the chassis
  3. The Screw into the chassis on the left edge
  4. The screw from the plastic link back into the board (this one is underneath another cover on the 7)

I want to emphasise that point on things being tight. Things can look good from a visual inspection but a quarter turn can make or break the connection, and another quarter turn is the difference in a phone never coming back for NFC. So it’s worth the time to double check.

Summary

In our experience these steps have fixed the vast majority of cases for us (we have had a NFC Chip fail on a single phone in the past however that’s out of the scope of this blog and will be something to cover more completely in the future).

But for how hopefully this will help clear through some of that return queue and let you get back to the stuff that matters. We’ve also covered this topic in a video which you can see below

If you’re curious about some of the tools we use or perhaps some devices to repair be sure to check out the listings on our website.

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