Tag: phone repair

Advanced iPhone Logic Board Diagnosis & Repair Course

Jan 2018 Shenzhen, China, the first phase of REWA Offline Training-iPhone Logic Board Diagnosis & Repair Refresher Course ( level 3 ) started.

Our participants came from 10 countries, including the U.S.A, France and Germany.

Also, REWA cell phone repair training online course is available now – REWA Academy, which is a platform that provides repair technique learning, practical demonstration, and idea-sharing for practitioners in the electronic repair industry.

Check REWA Academy out now!

After 12 days of training, our customers learned skills of logic board repair tools, LCD/OLED screen refurbishing, diagnosis & troubleshooting iPhone series typical malfunctions, de-soldering, re-balling and micro-soldering skills of chips and components.

Finally, all our customers received REWA Level 3 Certificates.

Meanwhile, we had a short interview with our customers towards 12 days of training.

Let’s check what do our customers say, does REWA Training really deserve your enrollment here: https://youtu.be/44sIz2tIEqM.

And now, our second issue of Offline Training is coming soon. Let’s see the following details.

Training Time: April ( 10 days in total ) Training Location: Shenzhen ● China

Application Deadline: Mar. 25, 2018 ( Limited Seats Available )

For more details about our repair training course, please check: http://bit.ly/3b5L1O1

Any further questions and demands please contact us at training@rewatechnology.com

December 7, 2023
REWA at MWC 2017: Key Highlights and Trends
The Mobile World Congress (MWC), the industry’s largest show, took place in Barcelona from February 27 to March 2, 2017. This gathering brought together mobile entrepreneurs and start-ups, and REWA was proud to be part of this significant event.

Major Trends at MWC 2017:

1. Smartphone Buzz:
- Big names like Huawei, Sony, Samsung, and LG showcased their latest Android devices.
- Huawei revealed the P10, featuring a 40% boost in battery life.
- Sony introduced four devices, including the XZ Premium with a 4K screen.
- ZTE presented two budget-friendly Blade V8 phones.
- Samsung launched tablets, while LG unveiled the G6 with a taller screen for dual app use.
- Meizu introduced “Supercharge” fast battery charging.
- BlackBerry’s KeyOne refreshed memories with its keyboard.
- Lenovo showcased a new lineup, including the Miix 320 and Yoga 720.
2. Drones and Robots Take Center Stage:
- A special “drone zone” featured DJI’s M200 enterprise drone and Softbank’s robot, Pepper.
- Pepper can greet customers and demonstrate products in shops.
3. The Rise of 5G:
- Despite ongoing technical standards development, 5G was a significant highlight.
- Anticipation for a download speed 1,000 times faster than the current US 4G average.
4. Insights Beyond Gadgets:
- While new gadgets and technologies made headlines, the real insight came from the booming electronic aftermarket.
- With increasing demand for devices like mobile phones and drones, the after-sale market for repair, recycling, and refurbishing services is thriving.
- The growing demand aligns with the rising movement for the “Right to Repair.”
MWC 2017 showcased not only the latest tech innovations but also the immense potential in the electronic aftermarket, reflecting a market ready for exploration and growth.
December 7, 2023
How to Fix iPhone XR Keeps Rebooting While Gaming: Full Chip-Level Repair Guide
Is your iPhone XR keeps rebooting, especially when playing games? You’re not alone. This common issue often stems from overheating at the chip level, causing the device to trigger Apple panic codes and enter a reboot loop. In this tutorial, we’ll walk you through a professional-level solution: chip-level board repair involving CPU, NAND, EEPROM, and baseband CPU transfer. Whether you’re a repair shop, technician, or DIYer, this guide will help you understand the root cause and how to fix it permanently.

Device Details

Model: iPhone XR

Announced: September 12, 2018

Customer Faced iPhone XR Keeps Rebooting

A customer’s iPhone XR would crash while playing games and then enter a constant reboot loop. The device wasn’t dropped, water-damaged, or improperly charged—ruling out external physical causes.

Step 1: Observe the Boot Loop

The phone repeatedly shows the Apple logo but fails to boot into iOS. Occasionally, it enters the system after several failed attempts.

Step 2: Analyze Panic Logs
We check the panic-full logs in the system. One key entry stands out:

AppleSocHot Hot Hot Hot...
This message indicates SoC (System on Chip) overheating, which causes the phone to reboot. This type of error often stems from internal chip failure rather than external factors.

Solution: Swap Encrypted Chips to Another Working Board

Due to the chip-level failure, a board swap with encrypted chip transfer is required. The following components need to be moved:
- CPU
- NAND chip
- Baseband CPU
- Logic EEPROM
Repair Process

1. Disassemble the iPhone and Remove the Motherboard

Open the phone and safely remove the motherboard.

2. Remove the Shielding Cover and Clean CPU
Use a hot air gun to remove the shielding cover.

Clean the thermal grease from the CPU.
3. Remove Black Glue & Detach the CPU
Carefully remove the black glue surrounding the CPU.

Reheat the area using a hot air gun.

Gently insert a thin blade while heating until the CPU chip is removed.
⚠️ Caution: Do not blow away the nearby Logic EEPROM (U1401) when heating.

4. Clean and Resolder the CPU
Clean the removed CPU and the board’s contact pads.

Reball and solder the CPU to a new donor motherboard.
5. Resolder the Logic EEPROM

Once the CPU is soldered, install the Logic EEPROM back in place.

Power-On Test

Connect the reassembled motherboard to a DC power supply and trigger the boot. A stable current jump to around 50mA indicates the CPU is functioning correctly.

Remaining Steps
Remove and reball the NAND chip and Baseband CPU from the original board.

Solder them onto the new motherboard along with the already-transferred CPU and EEPROM.
Reballing and soldering steps are similar to the techniques taught in REWA’s Handwork Course.

Final Testing

Once all encrypted chips are swapped and the board cools down, reassemble the phone.

Results:
All functions work normally.

The phone no longer reboots.

It runs games and videos smoothly for over 30 minutes with no crash or loop.
Conclusion

An iPhone XR keeps rebooting while gaming is typically suffering from a chip-level fault, especially overheating related to the SoC. The key solution is swapping all critical encrypted chips—CPU, NAND, Baseband CPU, and EEPROM—to a healthy donor board. Though this process requires advanced soldering skills and professional tools, it’s a proven and permanent solution. For repair shops and experienced technicians, this guide offers a reliable path to restore full functionality to affected iPhones.

Tools & Parts Used:

Tools:
- Hot air gun
- Thin blade
- Tweezers
- DC power supply
- Soldering iron
- Microscope (recommended)
- Thermal grease cleaner
- Reballing station (optional but preferred)
Parts:
- Donor iPhone XR motherboard
- Original iPhone XR CPU (encrypted)
- Original NAND chip
- Original Logic EEPROM (U1401)
- Original Baseband CPU
Technical Term Clarifications:
- AppleSocHot – A panic log error indicating SoC overheating.
- CPU (Central Processing Unit) – Main processor of the phone.
- NAND chip – Memory storage chip that holds iOS and user data.
- Logic EEPROM (U1401) – Stores logic configuration data.
- Baseband CPU – Handles communication functions like cellular and WiFi.
- Reballing – Reapplying solder balls to a chip to prepare it for resoldering.
June 7, 2022
How to Fix iPhone 12 Pro Overheating Issue
Have you encountered the dreaded “iPhone needs to cool down before you can use it” message on your iPhone 12 Pro? Overheating can cause your phone to become unstable, slow, or even shut down completely. This is a common problem faced by both technicians and phone users alike—but what causes it, and how can you fix it?

In this guide, we’ll take you through a real-life repair case involving an iPhone 12 Pro that experienced severe overheating due to a damaged earpiece flex cable. We’ll outline the repair steps, the tools used, and provide tips to help prevent similar damage in future repairs.

Symptoms of iPhone 12 Pro Overheating
- iPhone 12 Pro shows:
  “Temperature: iPhone needs to cool down before you can use it.”
- Heat is noticeably coming from the back cover
- Device shuts down or freezes due to high temperature
Troubleshooting Process
Disassemble the iPhone 12 Pro and remove the motherboard.

Connect the motherboard to a DC power supply and trigger the boot process.

The phone boots normally and current readings are within normal range, which means the motherboard itself is not causing the iPhone 12 Pro overheating.
🔍 Initial Diagnosis:

The issue likely originates from internal components other than the motherboard, such as flex cables, battery, or other connected modules.

Identifying the Real Culprit
- Upon close inspection, a crack was discovered in the earpiece flex cable. This component is often damaged during previous repairs like screen replacement, battery swaps, or logic board servicing.
- Over time, exposed copper wires on the flex cable can lead to short circuits, resulting in excessive heat generation.
💡 Tech Tip: Flex cables are thin and fragile. Improper folding or pinching can expose internal wiring, causing shorts that lead to iPhone 12 Pro overheating.

Repair Steps

Inspect the damage:

The crack on the earpiece flex cable was minor, so no need to replace it or jump wires.

Apply UV Solder Mask:
- Coat the damaged section of the flex cable with UV solder mask to insulate the exposed copper.
- Cure with a UV lamp for several minutes until hardened.
Reassemble the phone:
- Carefully reattach the motherboard.
- Pay extra attention to the earpiece flex cable during screen reassembly to avoid further damage.
Final Testing
Power on the device and run high-load tests such as video playback and gaming for 30+ minutes.

✅ Result: No overheating message, and the device remains cool and stable.
Tools & Parts Used

Tools:
- DC Power Supply
- UV Solder Mask
- UV Curing Lamp
- Screwdrivers and disassembly tools (plastic pry tools, tweezers)
- Anti-static gloves and mat (optional but recommended)
Parts:
- Original iPhone 12 Pro earpiece flex cable (not replaced but inspected)
- UV Solder Mask (for insulation)
Conclusion

This iPhone 12 Pro overheating issue wasn’t caused by a motherboard problem as initially suspected, but by a slightly damaged earpiece flex cable. By identifying and repairing the faulty flex using a UV mask instead of replacing the entire module, the issue was fully resolved.

When troubleshooting iPhone 12 Pro overheating problems, don’t overlook small internal components. Flex cables, dock connectors, or even a poorly executed battery replacement can all contribute to heating issues.

Lessons Learned
- Not all problems come from the motherboard.
- Precision matters. When handling internal parts like flex cables, be meticulous to avoid causing additional damage.
- A good repair technician must have strong diagnostic skills and pay attention to small details.
Stay Ahead in Mobile Repair

📢 REWA Academy launched iPhone 12 Pro Repair Course !

If you’re serious about mastering iPhone board-level and component repair, stay tuned and subscribe to REWA Academy for updates.

Enroll Now
June 5, 2022
How to Repair iPhone 12 Pro Water Damage: Step-by-Step Motherboard Fix
Water damage is one of the most common and frustrating issues faced by iPhone users—especially when the phone won’t power on. In this detailed repair guide, we’ll show you how to diagnose and fix an iPhone 12 Pro water damage and remains unresponsive, even after 20 days. You’ll learn how to disassemble the device, locate the short-circuited component, and restore full functionality by removing a damaged capacitor on the motherboard.

Whether you’re a repair technician, shop owner, or an experienced DIYer, this article offers expert-level insights and real repair case experience to help you successfully revive a water-damaged iPhone 12 Pro.

Step-by-Step Repair Guide: iPhone 12 Pro Water Damage Repair

1. Initial Inspection & Disassembly

Client complaint: The iPhone 12 Pro cannot boot after water damage and has been sitting for around 20 days.

Disassembly steps:
Remove the two screws at the bottom of the device.

Place the phone on a heating platform at ~70°C to soften the adhesive between the screen and the frame.

Use a plastic pry card to gently separate the screen.
2. Water Damage Indicators
- iPhones have Liquid Contact Indicators (LCIs) that turn red when exposed to water.
  - ✅ Indicator near the SIM card slot: Normal (white).
  - ❌ Indicator near the earpiece speaker: Turned red.
- Conclusion: Water likely entered the motherboard through the earpiece speaker mesh.
3. Screen & Motherboard Check
- Protect sensitive modules like the front camera, infrared camera, and dot projector.
- Remove the screen — no visible damage observed.
- Take out the motherboard and connect it to a DC power supply for testing.
  - Result: High current draw immediately after connection, indicating a short circuit.
4. Identifying the Faulty Component
- Visual inspection under a microscope: No physical damage or corrosion detected.
- Diode mode test reveals:
  - PP_VDD_MAIN line is shorted to ground.
- Use a thermal imaging camera while connected to DC power:
  - No heating component detected — the short must be internal.
5. Motherboard Separation & Deep Inspection
- Use a heating platform and hot air gun to separate the sandwiched motherboard layers.
- Upon inspection, a capacitor labeled C413_E appears discolored — likely damaged.
  - Based on repair experience, this indicates internal capacitor failure.
6. Remove the Faulty Capacitor
- Desolder and remove C413_E without replacing it:
  - Reason:
    
    It’s located near the middle layer — re-soldering could damage nearby connections.
    
    The Baseband CPU is adjacent — excessive heat could cause baseband failure.
    
    PP_VDD_MAIN has multiple filter capacitors — removing one won’t affect performance.
- Re-check the PP_VDD_MAIN line:
  - ✅ Short circuit resolved.
7. Reassemble and Test
Recombine the motherboard layers.

Reassemble the iPhone and power it on.

✅ All functions are working properly.
Tools & Parts List

🛠️ Tools Used:
- Heating platform (70°C)
- Hot air gun
- Microscope
- DC power supply machine
- Thermal imaging camera
- Plastic pry card
- Screwdriver set
- Multimeter (with diode mode)
🔩 Parts/Components Involved:
- iPhone 12 Pro motherboard
- Capacitor C413_E (removed, not replaced)
Technical Terms Explained
- PP_VDD_MAIN: The main power rail distributing voltage to critical components on the motherboard.
- DC Power Supply Machine: A diagnostic tool that simulates the iPhone battery, helping identify short circuits based on current flow.
- Thermal Imaging Camera: Detects abnormal heat to help find shorted components.
- C413_E: A small filter capacitor used to smooth voltage spikes — one of many on the PP_VDD_MAIN line.
- Diode Mode Testing: A multimeter function that checks for short circuits or open circuits by measuring voltage drop across components.
Conclusion

Water damage doesn’t always mean your iPhone is beyond saving. With the right tools and expertise, even a non-booting iPhone 12 Pro can be revived. In this case, the culprit was a shorted capacitor (C413_E) on the PP_VDD_MAIN line, which was successfully removed to restore full functionality.

If you’re a technician or DIYer, always proceed carefully when dealing with internal motherboard repairs. And for those looking to enhance their skills, REWA Academy’s iPhone 12 Pro Online Course is a great place to deepen your understanding.
June 5, 2022
iPhone 12 Won’t Boot After Drop? How to Fix Logic Board Damage Step by Step
When an iPhone 12 experiences a severe drop, it’s not just the screen or back glass that suffers—internal logic board components can also sustain serious damage. If your iPhone 12 won’t boot and only shows a fixed current of around 70mA on a DC power supply, this guide details a real-world board-level repair case. We’ll cover how to identify NAND or CPU damage, perform encrypted chip swaps, and restore the phone to working condition—perfect for advanced repair technicians, refurbishers, and repair shop owners.

Device Overview

Model: iPhone 12

Release Date: October 2020

Issue: Severe physical damage, screen/back cracked, cannot boot

Initial Diagnosis: Phone Doesn’t Boot

After disassembling the iPhone 12, the motherboard was tested using a DC power supply. The boot current remained fixed at ~70mA, a common indicator of NAND or CPU failure.

Internal Board Inspection

The motherboard was separated into upper and lower layers using a heating platform. Upon inspection:
- Some pads were missing.
- The NAND chip had a minor crack on the edge.
- The rest of the board looked intact.
Under normal circumstances, removing the NAND still allows the phone to connect to iTunes or 3uTools, but this one didn’t. This raised suspicion of CPU damage.

NAND & CPU Removal
1. Carefully removed black glue around NAND with a sculpting knife and heat gun.
2. Heated the chip until solder melted and pried it off.
3. Board under NAND was heavily deformed (seesaw-like).
4. CPU was then removed and inspected — no visible cracks or missing pads.
Chip Swapping Repair Process

Given the physical deformation, the likely fix involved transplanting key encrypted chips to a new board.
1. Swapped the following from the damaged board to donor board:
  - NAND chip
  - CPU
  - Logic EEPROM
2. Connected upper logic board to DC power — the phone booted successfully!
Signal Board Chip Swap

To restore network and connectivity functions:

Baseband CPU and Wi-Fi chip were also transferred to the donor signal board.

With both board layers temporarily connected for testing, the phone booted properly again.

Final Assembly
Upper and lower layers were permanently rebonded.

Phone was fully reassembled.

All functions passed — iPhone 12 fully restored!
Tools & Parts List
Tools:

DC power supply

Heating platform

Microscope

Hot air gun

Sculpture knife

Blade knife

Motherboard layered test fixture
Parts:

Donor iPhone 12 logic board

Replacement signal board

Logic EEPROM

NAND chip

CPU

Wi-Fi chip

Baseband CPU
Conclusion

Severe drop damage doesn’t always mean your iPhone 12 is unsalvageable. If it won’t boot and shows a 70mA current, a deformed board or NAND/CPU failure is likely. With careful inspection, encrypted chip transplants, and the use of donor boards, a skilled technician can revive a seemingly dead phone.

Got questions? Leave a comment or share your toughest iPhone 12 repair story below!
June 2, 2022
How to Fix iPhone X Apps Crashing Issue (Error 1100) – Step-by-Step CPU Resoldering Repair
Is your iPhone X constantly crashing whenever you open apps—even after a restore? You’re not alone. This issue is often linked to a deeper hardware fault, especially if you’re seeing iTunes restore error 1100. While software problems are a common culprit, in this case, the cause is more likely poor CPU soldering on the motherboard.

In this comprehensive repair guide, we’ll walk you through how to diagnose and resolve iPhone X app crashing problems by resoldering the CPU upper layer and properly reassembling the motherboard. Whether you’re a repair technician, DIY enthusiast, or run a repair shop, this guide offers actionable steps to bring the iPhone X back to life.

Model Overview

Model: iPhone X

Announced: 2017, September 12

Issue: Apps keep crashing after restore; iTunes reports error 1100

Defect Analysis: iPhone X Apps Crashing Issue

A customer brought in an iPhone X with persistent app crashing problems. Despite performing a full system restore just days before, the issue remained. We initially suspected a software glitch but ruled it out after another restore attempt via iTunes resulted in error 1100.

🔍 What’s Error 1100?

Error 1100 typically indicates a hardware communication failure, often related to the CPU or NAND soldering quality. In this case, the CPU’s upper layer connection was the root cause.

Repair Process: iPhone X CPU Resoldering & Motherboard Recombination

Here’s a breakdown of the hands-on repair process performed by REWA technicians:

Step 1: Attempt Restore via iTunes
Restored the device using iTunes → Error 1100 appeared

Diagnosis: Potential CPU upper layer soldering issue
Step 2: Remove the CPU Upper Layer
Tools used: Hot air gun, sculpture knife

Gently heat the CPU using a hot air gun

Carefully pry the upper layer off the chip with a sculpture knife
⚠️ Caution: Do not overheat. Avoid damaging the lower CPU layer.

Step 3: Clean the Tin Pads
- Remove residual glue using cleaning solvent
- Ensure all solder pads are clean and evenly exposed
Step 4: Solder the CPU Upper Layer Back

Tools used: Solder flux, tweezers, hot air gun
Apply solder flux to the CPU pad area

Align the upper layer with the lower layer using tweezers

Heat gently with a hot air gun and slightly press the chip

If the chip re-seats perfectly, soldering is successful
Step 5: Reassemble the Motherboard

Tools used: Heating platform
- Align both layers of the motherboard using tweezers
- Set heating platform temperature to 130°C
- Start heating. Continue for 1 additional minute once the motherboard sinks and solder flux flows out
Step 6: Final Testing
- Reassemble the phone
- Power it on and test:
  ✅ Apps launch normally
  ✅ All functions work as expected
Tools & Parts Used
- Hot air gun
- Sculpture knife
- Solder flux
- Tweezers
- Cleaning solution (for glue removal)
- Heating platform
- iTunes (for initial software restore)
Technical Terms
- Sculpture knife: A precision tool used to lift components or remove glue without damaging the PCB.
- Solder flux: A chemical agent that helps solder flow smoothly and prevents oxidation during soldering.
- Tin pads: The contact areas on the motherboard or CPU where solder connects components.
- Heating platform: A temperature-controlled base used to heat the motherboard evenly for soldering or reflow work.
- Motherboard recombination: Reassembling a split-layered motherboard (common in iPhone logic boards) using controlled heat and alignment.
Conclusion: Mastering iPhone X App Crash Repairs

Fixing the iPhone X apps crashing issue—especially those tied to iTunes error 1100—often goes beyond software troubleshooting. As this case demonstrated, poor soldering between CPU layers can disrupt app stability. By mastering CPU resoldering and motherboard recombination, you can restore functionality and save devices that might otherwise be considered irreparable.

Want to perfect your soldering skills? Join the REWA Academy’s iPhone Motherboard Repair Course for in-depth, hands-on training.
May 31, 2022
iPhone 12 Pro Boot Failure After Drop – Data Recovery & Logic Board Repair Guide
Have you experienced boot failure after dropping the iPhone 12 Pro? Drop damage is one of the most common causes of boot failure in smartphones. In this repair guide, we’ll walk you through the complete process of reviving a severely damaged iPhone 12 Pro that won’t boot due to a fractured double-layer motherboard. Moreover, we’ll show you how to recover lost data by swapping encrypted chips onto a donor board, such as irreplaceable photos. Whether you’re a professional repair technician or a DIY enthusiast, this article provides a deep look into advanced logic board repair methods.

Phone Overview

Model: iPhone 12 Pro

Announced: 2020, October 13

Damage Inspection:

After the drop, the iPhone 12 Pro showed a cracked screen and back glass. More concerning iPhone 12 Pro boot failure. The customer urgently needed to recover important photos from the device.

Initial Diagnosis:

Upon disassembling the phone, it became clear the double-layer motherboard was nearly separated due to the impact.
Removed the protective sticker on the NAND chip – visually intact.

Heated the board using a hot air gun and heating platform to carefully separate the two layers.
Chip Condition Check:
After separation, both the NAND chip and CPU appeared undamaged.

However, internal damage was found in the logic board’s rail area, indicating the board was structurally broken and beyond full restoration.
Chip Swapping Process for Data Recovery:

Considering that the board inside the rails is cracked and broken, the data recovery can be accomplished by swapping out the encrypted chip for a different one.

The first step is to carefully remove the NAND chip and CPU.

Remove the glue from the CPU pads, then clean them and reball them

Also, clean the pads on the NAND chip and reball it using the stencil, solder paste, and hot air gun.

We have now prepared the two most important chips.
Solder the CPU onto the new motherboard

Swapping the Logic EEPROM (stores calibration/configuration data).
Trigger Current Test:
Tested the board without the NAND chip installed.

Read a trigger current of 80mA, which is consistent with normal DFU mode—good sign.
NAND Installation & Boot Test:
Soldered the NAND chip back onto the new board.

Assembled and tested the device. Still wouldn’t boot.

Suspected dock flex cable damage. Re-tested the board by connecting only the battery and screen.
✅ The iPhone booted successfully.

Signal Board Repairs:
Reballed and reinstalled the Baseband CPU and Wi-Fi chip onto the baseband layer.

Cleaned the frame pads and rebonded the two motherboard layers together.
Final Testing:

After reassembling the iPhone 12 Pro:
All functions tested and passed.

Only the screen needed replacement.

The phone was successfully restored—full data recovery and operational. A true “full blood resurrection”.
Tools & Parts Used:

Tools:
- Hot air gun
- Heating platform
- Soldering iron
- Stencil for reballing
- Solder paste
- Tweezers
- Microscope
- Flux
- Logic board holder
- Cleaning solution (e.g., isopropyl alcohol)
Parts:
- iPhone 12 Pro motherboard
- Replacement screen
- Dock flex cable (if damaged)
- Thermal pads (if needed)
Technical Terms:
- Double-layer motherboard: The iPhone 12 Pro’s logic board consists of two layers soldered together, one handling signal processing (logic layer) and the other handling power and RF signals (baseband layer).
- NAND chip: The flash storage chip that contains user data such as photos and apps.
- CPU (Central Processing Unit): The phone’s main processing chip. In iPhones, it contains encrypted data tied to the NAND.
- Reballing: A process where you apply new solder balls to a chip to allow it to be soldered onto another board.
- DFU Mode (Device Firmware Update): A recovery mode that allows communication between the phone and a computer even when the phone isn’t booting normally.
- Baseband CPU: Controls cellular communication. It must be matched and reballed if swapped.
Conclusion:

Physical damage doesn’t always mean the end for your iPhone 12 Pro—especially if important data is at stake. With advanced microsoldering skills and the right tools, it’s possible to swap critical encrypted chips like the CPU and NAND onto a new motherboard, recovering full functionality and preserving user data. For professionals and skilled DIYers, this repair highlights the importance of precision, patience, and a strong understanding of iPhone logic board architecture.
May 29, 2022
Real iPhone XR Repair Cases: Boot Failure, No Display, Speaker Issues & Baseband Fixes
The iPhone XR remains a popular device, but like any smartphone, it’s not immune to hardware issues. Whether you’re a professional technician, repair shop owner, or DIY enthusiast, understanding real-world failure cases can help you troubleshoot and fix common problems more efficiently.

In this article, we share four practical iPhone XR repair cases covering issues such as failure to boot, speaker malfunctions, display problems, and baseband failure after a drop. Each case includes clear diagnostics, repair techniques, and component-level solutions to guide your repair process with confidence.

Case 1: iPhone XR Cannot Boot – High Current Draw on DC Power Supply

Symptoms:
- Phone won’t boot
- Large current spike when connected to a DC power supply
Diagnosis & Fix:

Using the rosin inspection method (a technique where rosin is applied to the board and heated to detect short circuits visually), a shorted capacitor—C5655—was found. This component is associated with the PP_DISPLAY_BL12_ANODE line, which powers the backlight.

Solution:

Replace the shorted C5655 capacitor. Once replaced, the short circuit disappears and the phone powers on normally.

Case 2: Speaker Rings Once, Then No Sound

Symptoms:
- The speaker makes a single ring or sound
- No audio afterward
Diagnosis & Fix:

This issue is typically caused by poor soldering of the speaker amplifier ICs. Diagnosing each chip individually can be time-consuming, so the recommended approach is to directly replace both speaker amplifier ICs: U5102 and U4902.

Solution:

Replace both chips. After replacement, the speaker function returns to normal.

Case 3: No Display, But Normal Boot Current

Symptoms:
- Screen remains black
- DC power supply shows normal boot current
Diagnosis & Fix:

Check the display connector and nearby components. The FL5752 inductor was found missing. This inductor is responsible for the PMU_TO_DISPLAY_RESET_CONN_L signal, which is crucial for initializing the display.

Solution:

First, test by jumping a wire across the missing inductor location. If the display lights up, replace the FL5752 inductor with one of the same specification to complete the repair.

Case 4: No Baseband Function After Drop Damage

Symptoms:
- Phone shows no service
- Baseband information missing
Diagnosis & Fix:
Focus on components related to the Baseband CPU, Baseband PMU, and transceiver IC. Start by removing the shielding cover with a hot air gun (avoid using a cutter to prevent damage).

Next, measure the diode readings around these chips. In this case, C906_K capacitor was found shorted. It is connected to the PP_1V3_SMPS3_XCVR_ANA power supply and acts as a filter.

Solution:
Replace the shorted C906_K capacitor with a new one of the same specification. This ensures long-term stability for the Baseband and RF functions.

(Tips: Use a hot air gun to remove the shielding cover slightly. Avoid using a cutter in order to prevent crack damage to the chips underneath)

Tools & Parts List

🛠 Tools:
- DC Power Supply
- Rosin + Heat Source (for rosin inspection)
- Hot Air Gun
- Multimeter (for diode value testing)
- Soldering Station
- REFOX Bitmap/Boardview Software
- Precision Tweezers
- Flux
🔩 Parts:
- Capacitor C5655 (PP_DISPLAY_BL12_ANODE line)
- Inductor FL5752
- Capacitor C906_K (PP_1V3_SMPS3_XCVR_ANA line)
- Speaker Amplifier ICs: U5102, U4902
Conclusion

These real-world iPhone XR function failure cases provide valuable insights into common hardware issues and how to fix them. From identifying shorted capacitors and missing inductors to replacing speaker amplifier ICs, the cases demonstrate how careful inspection and chip-level diagnosis can quickly restore devices.

Whether you’re an experienced technician or just starting with phone repairs, understanding these examples can enhance your repair skills and confidence. Always use boardview tools like REFOX for guidance and replace components with exact specifications to ensure long-lasting results.

Technical Term Explanation
- Rosin Inspection Method: A technique used to locate shorts by applying rosin and heating it. The spot with a short typically produces smoke or changes color first.
- PP_DISPLAY_BL12_ANODE: A power rail that supplies the display backlight circuit.
- PMU_TO_DISPLAY_RESET_CONN_L: A low-level reset signal from the power management unit to the display.
- PP_1V3_SMPS3_XCVR_ANA: A power supply line for the RF transceiver’s analog section.
- Diode Value Test: A multimeter-based test to identify whether small components like capacitors or diodes are shorted or functioning.
May 12, 2022
iPhone X Battery Replacement – Complete Guide

If your phone battery is in a low health condition, like 80%, it’s time to replace a new one. We will bring you a full case of iPhone X battery replacement as a reference.

All you need is a repair kit and a new battery. The repair kit should be included as below: tweezers, screwdrivers, pry piece, suction cup, heating pad, spudger, battery adhesive, and waterproof adhesive.

Firstly, please long press the phone to turn it off. Then you can use a pentagon screwdriver to unscrew the screws at the bottom of the phone.

Please pay attention to putting the screws aside well. You can place the screen face down on the pad for about 2-3 minutes after the heating pad is up to the temperature of 70—80°c.

And fix the suction cup at the bottom of the phone, lift the screen gently, and insert a pry piece underneath. Gradually move around the edge of the display, separating the screen along the gap.

The display assembly is still connected to the iPhone by cables, so don’t try to remove it completely. Again, please pay attention to the position of the cable to avoid damage.

The angle should not be greater than 90 degrees to prevent breaking the flex cable. The process of removing the cover is done.

Next, use a Tri-wing screwdriver to unscrew the screws on the shielding cover of the cable connector. You can use a spudger slightly to extricate the battery and the connector between the screen and the motherboard.

Now, continue to follow instructions step by step. Detach the earpiece speaker flex cable, and remove the old display assembly.

Then, please use tweezers to clean up the battery adhesive. It’s suggested to detach the Taptic Engine and loudspeaker better to remove the adhesive at the bottom of the battery.

Again, use a Tri-wing screwdriver to unscrew the screws on the speaker flex cable and detach the shielding cover.

After taking out the loudspeaker and Taptic Engine, let’s continuously remove the battery adhesive. Because the adhesive at the bottom of the battery has been for a long time, it’s hard to remove it. We need to drop some alcohol to help clean up.

Drop the alcohol around the edge of the battery, and leave it to penetrate and evaporate. Use tweezers to make it loose, take out the old battery, and continue to remove the rest adhesive.

Please keep removing the waterproof adhesive around the frame. And replace the Taptic Engine and loudspeaker. Remember to tighten the screws and replace them with the new battery.

Tear off the film of the battery adhesive, and make its glue adhere to the battery. Press it slightly, and tear off the film. Please put on the new battery, and press it slightly.

Use a spudger to disengage the battery connector. Reassemble the display cable, touch the cable, and continuously.

Please turn it on. Check the health condition of the battery. It shows the maximum capacity of the battery now is 100%. Please turn it off. Tear off the waterproof adhesive. Make it adhere to the phone body. Press lightly with tweezers to make it adhesive.

Tear off the film. Reassemble the display cable and touch the cable. Reassemble the earpiece speaker flex cable, and connect the battery. Install the shielding cover, and tighten the screws.

Take off the waterproof adhesive around the frame. Buckle the phone screen.

Please turn it on again. Let’s do some battery tests. First is the wired charging test. Next is the wireless charging test. It’s working. Both are working.

The above guidance is about the battery replacement process. If you have any problems or advice, please leave us a comment below.

April 29, 2022
Troubleshooting iPhone 13 Face ID & Display Message Issues after Screen Replacement

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.

April 22, 2022
Troubleshooting iPhone Restarting Issue

For what reason does my iPhone continue to restart, and what do I do about it? We trust our iPhones and they need to work constantly.

It would be great if there was a solitary reason behind why iPhones restart again and again, yet there is certifiably not a magic slug for this issue.

In this article, I’ll disclose what makes iPhones keep restarting and I’ll tell you the best way to fix the issue.

For what reason Does My iPhone Keep Restarting?

iPhones that continue to restart for the most part fall into two categories:

1. iPhones that restart discontinuously: You can use your iPhone for some time with no issue by any means, and afterward your iPhone unexpectedly restarts.

2. iPhone restart circle: Your iPhone consistently restarts and it’s unusable. The Apple logo shows up and vanishes on the screen, again and again.

Assuming your iPhone falls into the subsequent category, skirt ahead to step 5. It’s difficult to do the initial few steps if you can’t utilize the software on your iPhone.

1. Back Up Your iPhone

Before we do any troubleshooting whatsoever, ensure your iPhone is backed up.

If your iPhone has a hardware issue, this could be your last opportunity to back up your information.

If we want to, we’ll restore your iPhone in a later step, and you need a backup before you restore.

Once you’re backed up, you’ll be prepared to begin fixing the issue.

2. Update Your iPhone’s Software (iOS)

Like Windows on a PC or macOS on a Mac, iOS is your iPhone’s working framework. iOS updates consistently contain heaps of fixes for programming bugs and different issues.

Once in a while, a software update fixes the issue that is making your iPhone continue to restart or enter a restart loop.

To check if any software updates are available, go to Settings – > General – > Software Update. If an update is available, install it.

You can also connect your iPhone to your PC and use iTunes (PCs and Macs running macOS 10.14 or older) or Finder (Macs running macOS 10.15 or newer) to update your iPhone’s software.

If your iPhone is consistently restarting, iTunes or Finder may be your smartest option.

3. Decide whether An App Is Causing Your iPhone To Restart

It’s extremely intriguing for an application to make an iPhone restart or turn on and off more than once. Generally, the software on your iPhone is protected from issue applications.

That being said, there are over 1.5 million applications in the App Store and they’re not all perfect.

If you installed an application not long before your iPhone entered a restart loop, uninstall that application and check whether the issue settles itself.

Settings – > Privacy – > Analytics & Improvements – > Analytics Data is somewhere else to check for issue applications. It’s typical to see a few sections in this rundown.

Quickly scroll through the list and search for any applications that are recorded again and again. If you see one, uninstalling that application might fix your iPhone.

4. Reset All Settings

Reset All Settings is certifiably not an enchanted shot, yet it can resolve specific software issues. Go to Settings – > General – > Transfer Or Reset iPhone – > Reset – > Reset All Settings to restore your iPhone’s settings to factory defaults.

You will not lose any of your applications or information, yet you will have to enter your Wi-Fi password once more.

5. Remove Your SIM Card

iPhone restart loops can be caused by issues with your iPhone’s connection to your wireless carrier.

Your SIM card connects your iPhone to your wireless carrier, so removing it is the most ideal way to troubleshoot issues where your iPhone continues to restart.

Sit back and relax: Nothing can turn out badly when you remove your SIM card. Your iPhone will immediately reconnect to your carrier when you set it back in.

If removing your SIM card fixes the issue, put the SIM card back in your iPhone.

If the issue returns after you put your SIM card back in, you’ll have to restore your iPhone (step 7) or replace the SIM card with your carrier.

On the off chance that removing the SIM card doesn’t fix the issue, don’t put your SIM card back in until you’ve finished the subsequent step.

6. Hard Reset

You shouldn’t do a hard reset on your iPhone except if it’s totally necessary.

It’s similar to switching off a workstation by unplugging it from the wall. That being said, an iPhone restart loop is one of those times when a hard reset is justified.

To play out a hard reset, hold the power button and Home button simultaneously until your iPhone screen goes blank and the Apple logo reappears.

On an iPhone 7 or 7 Plus, the buttons you need to press to execute a hard reset are somewhat unique. At the same time press and hold the power button and the volume down button.

Assuming you have an iPhone 8 or newer, the process of hard resetting is also different.

Press and release the volume up button, then, at that point, the volume down button, press and hold the side button.

Notwithstanding what model iPhone you have, ensure you hold the two buttons down together for no less than 20 seconds.

If you removed the SIM card from your iPhone in the previous step, this moment’s a decent opportunity set it back in your iPhone.

We’ve eliminated the possibility that your SIM card is making your iPhone restart.

Ideally, the hard reset will fix the issue where your iPhone continued to restart, yet on the off chance that it proceeds, you’ll need to reset your gadget by adhering to the guidelines underneath.

7. Restore Your iPhone

Restoring your iPhone eradicates and reloads the iPhone’s software (iOS), and it can dispose of a huge number of programming issues simultaneously.

At the point when we restore your iPhone, we’ll eliminate the possibility that a software issue might be making your iPhone restart – that is the reason Apple specialists get it done so regularly.

Your iPhone should be connected to a PC to restore.

I suggest doing an exceptional sort of restore that Apple specialists do call a DFU Restore, which goes further than a normal restore and can tackle more issues.

After the restore gets done, you’ll have the option to reload all your data from your iPhone backup in iTunes, Finder, or iCloud. If you still have an issue, return here and continue to peruse.

8. Check For A Hardware Problem

Hardware issues are a typical reason why iPhones stall out in a restart loop. If you’re utilizing a case on your iPhone, remove it before you proceed.

Intently check out the charging port on the lower part of your iPhone. Verify whether any trash is stuck inside and for indications of corrosion.

If something doesn’t look right, snatch a toothbrush you’ve never utilized and delicately brush out the charging port.

A short circuit or other issues inside the charging port can cause a wide range of issues with your iPhone.

9. You May Need To Repair Your iPhone

We’ve eliminated the possibility a software issue is making your iPhone continue to restart and we’ve checked for hardware issues outside of your iPhone.

Assuming your iPhone is in a restart circle, your iPhone likely should be fixed.

If you decide to find support at your neighborhood Apple Store, ensure you have an appointment with the Genius Bar so you don’t need to stick around.

Summary

By this point, I wish we’d fixed the issue that made your iPhone keep restarting.

I would like to hear your experience and questions in the comments section below.

April 21, 2022