Dot projector parts are extremely fragile. A fall or water damage may harm dot projector parts, inducing Face ID not working. Since the dot projector IC is encrypted and replacement requires data encryption bonding for the new IC, repair technicians find it a challenge to repair the Face ID. The good news is that REWA LAB has developed a simple and efficient method to repair the Face ID. Let’s check it out!

Go to Settings, Face ID & Passcode, and Set Up Face ID. When trying to set up Face ID, “Move iPhone a little lower/higher” pops up. Face ID cannot be normally set up. It can be judged that the dot projector of the Face ID has malfunctioned.

Remove the display and then detach the Face ID module. We can see a red mark, which indicates that the phone has water damage.

Connect the dot projector flex cable with the I2C Repair Programmer. The test shows that the dot projector flex cable has malfunctioned.

Press “Read” and read the data from the dot projector flex cable.

Connect a new I2C iPhone 11 Pro Max flex cable to the programmer. Press “Write” and write the data that has been read on the new flex cable.

Dip a small amount of UV Adhesive on the crystal of the dot projector flex cable and solidify it with UV Lamp. This step is aimed to fix the crystal.

Remove the foam on the back of the dot projector.

To make positioning easier while assembly, mark the module with Sculpture Knife.

Since the dot projector flex cable is under the metal plate, lift the metal plate to remove the flex cable.

Get the Holding Fixture. We use Wextom Face ID Module and Dot Projector Board Holding Fixture for the repair.

Attach the Face ID module to the Holding Fixture and grind the welding position of the metal plate.

Insert the pry knife into the gap between the dot projector module and the crystal. Heat with Hot Air Gun at 150℃ and remove the dot projector flex cable.

Heat with Hot Air Gun at 320℃ and detach the dot projector module.

Attach the dot projector module to the Holding Fixture. Heat with Hot Air Gun at 320℃ and take out the MOSFET.

Apply a small amount of Solder Paste to the bonding pad with Soldering Iron at 365℃. Jump wire between pin 2 and pin 3 of the MOSFET with 0.02mm copper wire.

Attach the dot projector module to the holder. To clean the tin on the dot projector module, smear rosin with Soldering Iron at 365℃ and solder-wick.

Clean the module with PCB Cleaner afterward. Heat with Hot Air Gun at 240℃ and remove residual adhesive with tweezers.

Get the new flex cable. Put the Reballing Stencil in the right position and apply some medium-temperature Solder Paste evenly.

Heat with Hot Air Gun at 320℃ and remove the Reballing Stencil after the flex cable has cooled.

Heat with Hot Air Gun at 320℃ again and apply a small amount of Paste Flux to the flex cable.

Fix the flex cable to the holder and align the dot projector module.

Solder with Hot Air Gun at 320℃. Connect the flex cable that has been soldered to the I2C programmer.

Press “Test” and the screen shows “Pass” which indicates that the flex cable is normal.

Attach the flex cable to the Holding Fixture and put the dot projector flex cable in position. Apply a small amount of 460 Adhesive between the dot projector module and the crystal. Once the adhesive has set, arrange the flex cable.

Install the flex cable on the phone. Boot up the phone, and go to Face ID settings. Face ID is set up normally and unlocks normally. The fault is cleared.      

Please feel free to visit our online shop for repair parts and tools.

For more Face ID content, please read the articles below.

Watch the video below to get a more detailed iPhone 11 Pro Max Face ID repair.

Recently, Phone Repair Guru posted a video about iPhone 13 screen replacement. After replacement, “Important Display Message” pops up. What’s worse, Face ID is not available.

Since the iPhone 13 screen includes no flood illuminator module and all the parts for the TrueDepth system are housed in the iPhone itself,

REWA LAB speculates that the chip on the original screen has saved Face ID data. Transferring the chip to the new screen might solve the problem. Today, let’s verify this speculation.

In the first place, we test the Face ID function of iPhone 13. True Tone function is normal. Face ID can be set up and is working fine.

Then we disassemble the phone and try to replace the screen with an original and genuine one. Remove the original screen. Detach the sensor flex cable with Hot Air Gun at 100 °C. Please be careful not to damage the flex cable when you remove it. 

Attach the removed sensor flex cable to the new screen. Install the screws. Connect the new screen. Turn on the phone.“Important Display Message”  appears. Face ID can’t be set up. True Tone disappears.

Next, we try to transfer the IC on the original screen to the new screen. Remove the new screen. To prevent scratches on the screen during operations,

apply a protective film to the screen. 

Heat the screen flex cable with Hot Air Gun at 100 °C. Gently pull up the flex cable. To protect the screen, insert the reballing stencil under the flex cable for insulation. Apply high-temperature tape.

Remove black adhesive around the chip with Hot Air Gun at 240 °C. To remove the chip, set the temperature to 300 °C and airflow to 6.

Apply some middle-temperature Solder Paste. Clean the bonding pads with Soldering Iron at 360 °C and solder wick. Keep cleaning the bonding pads with PCB Cleaner.

Next, remove the chip on the original screen with the same method.

Clean tin on the chip of the original screen. Apply some middle-temperature Solder Paste to the bonding pads. Clean tin and black adhesive on the bonding pads of the chip with Solder Wick. Keep cleaning the bonding pads with PCB Cleaner.

Next, reball the chip. Put the reballing stencil in position. Apply a layer of middle-temperature Solder Paste evenly. Heat with Hot Air Gun at 300 °C to form the solder balls. After the solder balls are formed, clean with PCB cleaner.

Apply Paste Flux to the bonding pads of the new screen. Align the chip of the original screen. Solder the chip with Hot Air Gun at 300 °C.

Remove high-temperature tape after the flex cable has cooled. Connect the screen. Turn on the phone. There is no “Important Display Message”. Face ID can be set up and is working fine. But True Tone hasn’t been restored.

Apple has long faced criticism for displaying prompts like “Important Battery Message” and “Important Camera Message”, which makes it difficult for third-party repair stores to fix their products.

With the ‌iPhone 13‌ this year, Apple further makes it more difficult for customers to get repairs from third-party stores. However, it is risky to replace the chip to solve Face ID not working after iPhone 13 screen replacement. REWA LAB does not recommend that non-professionals try this method. Apple could patch this via an iOS update in the future. Let’s wait and see. Please feel free to leave your thoughts on the problem.

Face ID Not Working 'Move iPhone a Little Lower/Higher' is usually caused by damage to the dot projector and the problem is confirmed to be almost unrepairable. However, there is finally a solution to fix the problem. Today REWA LAB will show you the latest dot projector repair technique!

Problem  

When trying to set up Face ID on the iPhone, we get the message 'move iPhone a little lower/higher'. Next, switch to the front camera, we found that the name of the lighting effect ‘Natural Light’ stays the same when the camera detects a person's face. What's more, the pop-up notification keeps saying ‘Move farther away’. Normally, when Portrait mode is ready, the name of the lighting effect ‘Natural Light’ should turn yellow. Judging by this, the dot projector or relevant circuits of the dot projector might have malfunctioned.

Diagnosis 

Take apart the phone and remove the display assembly first. We can see that the dot projector has been water damaged and the crystal on the dot projector is broken. Take out the front camera assembly carefully. Here we recommend using a repair programmer to check the dot projector flex cable. Connecting the dot projector flex cable with the programmer, the results show ‘Fusing’ which means the dot projector flex cable has been damaged. We need to burn data of the original dot projector flex cable onto a new one and then replace the broken crystal.

Troubleshooting   

In the first step, we should separate the crystal from the cable. Compared to traditional operations with a hot air gun, we prefer to use an intelligent preheating platform. Put the dot projector into the matching rubber mold and separate the crystal from the flex cable carefully with the blade.  Next, we use the repair programmer again to burn the origin data onto the new dot projector flex cable. After completing these two steps, we need to solder the dot projector module and glue a known-good crystal. For detailed instructions, click on the video at the bottom of the article.

Reassemble and Test 

Apply double-sided adhesive tape on the backside of the front camera, and adhere the dot projector flex cable to the right position. Get the front camera assembly installed and get the logic board assembled and buckle the display assembly. Face ID can be set up successfully, and the phone can be unlocked with Face ID this time.  Tips: The double-sided adhesive tape used here is for the test. We need to glue the dot projector module onto the flex cable after fault clearance.

Tools Used

Tweezers

Soldering Station & Material Set

Medium-Temperature Solder Paste

Hot Air Gun

Intelligent Preheating Platform

Visit our online shop for more parts and tools.You can also visit REWA YouTube Channel to check our video.