i-Device/s Burning Pin #4 on Lightning Bolt Connectors


I was starting to think that I was going mad… Why does every lightning cable - Apple or 3rd party - always develop a blackened 4th/5th pin??? Is one of my devices faulty, and causing this problem? I’ve just purchased 2 new cables in the past month and already 1 has died from this…

Then I googled… and found a lot of other people are having the same experience.

I don’t know if it’s likely to be ALL of my devices adding to the problem… or a specific device… If any, I suspect my wife’s iPhone 5S, purchased around 1 year ago… but I know trying to single a device out in this household will be impossible… so I guess I’m left having to keep buying more cables… :frowning:



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None of my cables are exhibiting this issue!

A bit more googling, some people say they posted on Apple Communities and were contacted by Apple directly, seeking to give them a replacement in exchange for the faulty cable for examination…

Seeing this issue a lot with devices and cables that come in for service, Still haven’t determined the exact cause, but looking at the pinout diagram, that appears to be the main contact for transferring power.

Would explain why they stop charging then…

It’s only been in the past 12-18 months that they’ve started doing it, which makes me think it might be my wife’s iPhone 5S - would fit the time frame approximately. I never noticed it before then with our other lightning devices. Have spoken to her and we’re going to try only charge her phone with the same cable and see what happens.

In order - 2 Apple cables, then the 2 new ones from Kmart that were purchased around Xmas. I didn’t take a reverse shot, but they are the same - 4th pins, black. The 2 Apple ones are dead - wont talk/charge - and I’ve chucked out 1-2 (more?) other Apple cables with the same issue. The white Kmart cable still works if you connect it the “right” way, but tends to “bounce” a bit first til it finds a good spot. The silver cable still works - but you can see the corrosion (?) starting.

Someone said to try rubbing alcohol… so I’ve just given 1 of them a rub with some Iso. It does look like it cleaned it up a little bit… but only minor change. Worried I’ll destroy it - but then, it already is failing to work.

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I’m sure I’ve seen this mark before and just grabbed the nearest cable to me to check. While this one looks pretty good, you can see that pin is developing a darker ring around the outside of it. This cable has likely been shared around devices so who knows.

I then went on a hunt to check out other cables… This is the one hooked up to my Wifes MacBook Air that she uses to charge her iPad most of the time (and sometimes phone). She did have an iPhone 5S, although that was replaced when the 6S came out. I think this is still working (at least she hasn’t complained :stuck_out_tongue: )

Side 1:

Side 2:

I’m actually wondering if leaving it plugged in all the time and using the device could be a factor here. The charger that sits beside her bed looks clean.

I just whipped out the USB microscope (in all it’s 640 x 480 glory)…

This is the two side of my Wifes cable. You can see a couple of small marks on one side, then a couple of shots of the other side.

Phew, “we” aren’t just crazies!

I wonder why it happens for some and not others. I’ve just checked all my cables and every one of them is clean. Some are used sporadically and one, plugged into my Air, is used constantly (plugged in 24/7 most of the time). No sign of corrosion.

I think it must be a particular device in our house, but whether it’s the same device for everyone or not…?

Maybe… I’ve got my Air2, Mini1, 6S and 5S all accessing most of the cables at one time or another. The Air2 cable is only ever also used by the 6S. So its possible. Maybe the lightning port itself is faulty in some way on some devices? Who knows…

I’ve got it both of the cables next to my bed. Definitely worse on my iPad charger but that’s because its older. I have noticed the cable connected to my iPad charger only charges when plugged in one way.

But at least they’re not fraying right? ¯_(ツ)_/¯

I’m guessing this would be the result of arcing when making electrical contact between the cable (Pin 5 being +power) & charging port.

No big deal, it would cause somewhat of a slightly higher resistance (albeit negligible)…so grab a cotton tip, give it a bit of rub to clean it off & should be good for another year or so.

Btw, if it doesn’t work after the contacts are clean then you’ve got further issues. Possibly the cable, the opposing contact on the phone/ipad port itself or even the pin itself is corroded/pitted (see last photo above) that it’s not actually making contact.

I have this on one side of one of the three leads I have. Fascinating how widespread it is!

I reckon this. It is most likely a spark as the cable is inserted with the resultant carbonisation. Just clean it. If it really worries you, turn the charger off at the mains before plugging in the idevice.

I have tried cleaning the pin… Maybe I’m expecting instant results but should be running a marathon? Doesn’t just “wipe off”, even with firm scrubbing with qtip and isopropal. That’s why I chucked a couple cables out - couldn’t get them working again.

I’ll try some more…

Yes, you are right. This would be the correct procedure when charging to minimise arcing at the point of contact between the lightning connector & charging port.

Also, it wouldn’t hurt to clean the lightning cable pins as well as the charging port on your iPhone/iPad regularly (ie every 2-3 months). This will prevent the carbon from building up on the contact surfaces over time.

You’ll find that the damage to the surface of these pins (& may even be on the port itself as well), has already been done, most probably pitting. Pitting is a type of corrosion. As a result of the pitting, after cleaning the carbon away, it may not be making (enough) electrical contact with the mating surface (to the charging port).

Ok, more iso and qtips… scrubbing but really not much change. The silver cable has come up a little

So - walk into Apple Store with 2 iPhones and 3 iPad and say - One of them is burning my cables! ??? Even if they could identify the issue in one/multiple devices, if it’s not on a Repair Program, would they do anything?

IListening to the Accidental Tech Poscast #211 and they mentioned this issue in passing. They were saying that it’s caused by failing little springy bits inside the port on the iOS devices. As it no longer makes contact properly it causes arcing and hence the scorch marks… (which was already mentioned in this thread).

Apparently a warranty issue if you’re lucky :slight_smile: