A customer brought me an iPhone 5c (A1532) which was not taking a charge and would not turn on. The most common failure point is a bad charge port on the iPhone, but testing it with a new one resulted in absolutely no current getting into the phone. Replacing the battery with a charged on resulted in the phone powering up meaning it had not taken serious damage.
Troubleshooting a logic fault in something as compact and electrically dense as an iPhone is mostly beyond my capabilities so a Google search resulted in some info about a faulty charge controller IC. The IC is an NXP part, model 1610A1 and comes in a 36 pin BGA package used in several Apple product lines for managing the charging circuitry. It can be ordered online for a few dollars which is the good news. The bad is that it measures only 2.1 x 2.1mm. Here’s a photo:
Image showing how small the faulty IC is
As can be seen it’s not exactly the easiest thing to replace, especially being a BGA since as the name implies (ball grid array) they require balls of solder to be adhered to the chip to make proper contact with the board.
I attempted this by backing up the contents of the phone and removing the main PCB from the iPhone. After removing the PCB, the entire rear is covered by a soldered on metal shield. To remove it I clamped the board in my helping hands tool along with a lot of heat from a hot air gun and some careful prying. I found it worked best to apply heat to one end and pull, and move the hot air back as the shield comes off. Once removed you’re greeted with a lot of components:
Donor logic board with IC desoldered
The above pic is of the donor board, after I removed the IC. You can see the grid of solder pads where it once was. To remove I just applied heat over the chip and used a very fine pair of tweezers and pulled directly upward while heating. The instant the solder becomes liquid the chip pops off and you can stop applying heat.
After repeating this procedure to the good phone, I prepped the board and IC for resoldering. This is the most important step and involves solder flux. I put a glob on the bottom of the chip and used my soldering iron to wipe solder across the pads which results in them being clean but also leaves a puddle of solder on each pad, which is key for resoldering using hot air. I did the same thing to the board.
BGA clean and ready for resolder
Before and after prep:
Once the board was prepped it was simply a matter of aligning the IC to the pads and applying hot air to reflow the solder. Since both the IC and the board had semi spherical solder globs on them, the two didn’t want to align perfectly and took a bit to get it right. It doesn’t have to be absolutely perfect though since solder has a lot of surface tension and will pull the chip into alignment when liquid.
And finally the completed board:
IC moved to the new board
Overall it took about an hour and the phone now works as it should. The cause of the failure is still up in the air. People claim using cheap chargers or even simply non Apple branded ones can cause this particular failure.