iPhone XS Max Face ID Repair Guide: Fixing Dot Projector Issues

The commonplace error message "Move iPhone a Little Lower/Higher" that appears when Face ID is not functioning properly is often the result of damage to the dot projector. In this article, Phonefix provides a comprehensive guide to repairing the Face ID issues on your iPhone XS Max.

By replacing the faulty dot projector, you can restore your iPhone's Face ID functionality and avoid the inconvenience of having to constantly adjust the positioning of your device.

Tools Required

To complete this repair, you'll need the following tools:

• JCID V1S Pro or JC V1SE  Repair Programmer
• Hot air soldering station
• Other assistant tools

Step 1: Identifying the Problem

The iPhone XS Max's Face ID feature is not working properly. When attempting to set up Face ID, the message "move iPhone a little lower/higher" appears.

Additionally, when using the Camera app and selecting Portrait mode with the front camera, the lighting effect "Natural Light" does not turn yellow when it should, and the pop-up notification keeps saying "Move farther away."

These issues suggest that the dot projector or relevant circuits of the dot projector may have malfunctioned.

Step 2: Diagnosing the Issue

To diagnose the issue, disassemble the phone and remove the display. Upon inspection, it is clear that the dot projector has been water damaged, and the crystal on the dot projector is broken.

Remove the battery adhesive strips, and take out the front camera assembly. Connect the dot projector flex cable to a repair programmer, and the result "fusing" indicates that the dot projector flex cable has been damaged.

To address the issue, data from the original dot projector flex cable need be burned onto a new dot projector flex cable, and the broken crystal needs to be replaced with a new one.

Step 3: Separating the Crystal from the Cable

To separate the crystal from the cable, the bracket securing the infrared camera and the dot projector need to be carefully cut off. The front camera, the dot projector, and the infrared camera must then be placed in corresponding slots on the heating platform.

Once the adhesive has been softened, the dot projector flex cable can be removed carefully. It is important to be cautious when taking down the dot projector flex cable, and one can wrap their hand with a lint-free wiper to avoid damaging the front camera.

The dot projector should be placed into the matching rubber mold, heated with the soldering iron at about 365℃, and the crystal should be separated from the flex cable carefully with a blade.

Step 4: Burning Data

To burn data from the original dot projector flex cable onto a new dot projector flex cable, the original dot projector flex cable should be connected to the repair programmer, and the data should be read and saved.

Then, a new dot projector flex cable should be connected to the repair programmer, and the saved data should be burned onto the new dot projector flex cable.

Step 5: Jump-Wiring the MOSFET

To jump-wire the MOSFET, the MOSFET should be grounded with a grinding tool, and then heated with a Hot Air Gun to take down the dot projector module.

The residual parts of the MOSFET should be cleaned with tweezers, and some medium-temp solder paste should be applied to the bonding pad.

The bonding pad should be tinned with a Soldering Iron, and 0.02mm Enameled Copper Wire should be used to connect Pin 2 and Pin 3 of the MOSFET with the wire.

Step 6: Soldering the Dot Projector Module

To solder the dot projector module, the module should be turned over, and any residual adhesive should be cleaned with a sculpture knife. Then, it should be cleaned with Solder Wick thoroughly and with PCB Cleaner afterwards.

The BGA reballing stencil should be placed in the right position, and some medium-temp solder paste should be applied. The module should be heated with a Hot Air Gun to get it reballed.

The new dot projector flex cable should be attached to the PCB Holder, paste flux should be applied to the new dot projector flex cable, and the dot projector module should be soldered with a Hot Air Gun.

The device should be cooled for 2 minutes, and the new dot projector flex cable should be connected to the repair programmer. The result "normal" indicates that the infrared light emitted from the projector is normal.

Step 7: Gluing a Known-Good Crystal

To glue a known-good crystal, some glue should be applied to the dot projector module, and the crystal should be placed in the right position.

It is important to be cautious when lining up the crystal with the module, as an alignment error might also affect the functionality of Face ID.

Step 8: Testing

To test the device, double-sided adhesive tape should be applied to the backside of the front camera, and the dot projector flex cable should be adhered to the right position.

It is important to note that the double-sided adhesive tape used here is for test purposes only, and the dot projector module must be glued onto the flex cable after fault clearance.

Once the phone has been reassembled, test by going to Settings > Face ID & Passcode > Set Up Face ID. If Face ID can be set up successfully, and the phone can be unlocked with Face ID, the repair has been successful.

By following these steps and using the right tools, you can fix your iPhone XS Max's Face ID not working issue caused by a faulty dot projector.