A stunning flagship was introduced by Xiaomi in May 2018, the Xiaomi Mi 8. It quickly gained popularity among smartphone enthusiasts because. Accidents can happen to even the most advanced technology, as one unfortunate Xiaomi Mi 8 owner discovered. The incident involved a severe drop that caused extensive damage to the rear cover and front screen glass of the Xiaomi Mi 8. The phone was also found to have suffered serious motherboard damage, rendering it unrepairable. This blog post, however, will discuss how to repair Xiaomi Mi 8 Drop Damage.
Phone details
Model: Xiaomi Mi 8
Announced: 2018, May
Defect Phenomenon
A Xiaomi Mi 8 was severely damaged in an accident, resulting in both the rear cover and front screen glass being heavily cracked. The phone was taken to a repair shop, where it was diagnosed with serious motherboard damage, making it seemingly unrepairable. However, the owner needed to retrieve important pictures and videos stored on the device.
Troubleshooting
1: Initial Assessment
- Due to the severe damage, it is assumed that the screen is broken and the motherboard may be cracked.
- Disassemble the phone to examine the motherboard for any visible signs of damage.
2: Motherboard Inspection
- Upon inspection, there are no prior repair traces, but the motherboard is significantly deformed.
- The shielding cover over the CPU and PMIC (Power Management Integrated Circuit) is also uneven, indicating possible internal damage.
3: PMIC Check
- Remove the shielding cover on the PMIC to inspect the chips and components.
- Two capacitors are found to have poor soldering and fall off easily when touched. As they are filter-type capacitors, they are not critical to the immediate repair and can be ignored for now.
- Remove the PMIC to inspect the pads on the PCB. Fortunately, there are no missing pads or broken rails.
- Reball the PMIC and solder it back onto the PCB.
4: Testing the Phone:
- Reassemble the phone temporarily to test it.
- Connect it to a USB cable to charge, but there is no charging current. Attempt to boot the phone, but it fails to start. This suggests the issue is not related to the PMIC or capacitors.
5: CPU Examination
- The CPU appears cosmetically intact, with no visible cracks or signs of poor soldering.
- Despite this, the CPU is resoldered as a precaution. The CPU consists of two layers: the upper layer is RAM, and the lower layer is the core CPU.
- Remove and clean the layers, then resolder the chips using stencils.
6: Further Testing:
- After reassembling the phone, connect it to the charging cable again, but still, there is no charging current, and the phone does not boot.
- Given the serious drop damage, it’s likely that internal PCB rails are broken
Repair Process
1: Chip Swapping
- To attempt recovery, the CPU and UFS (Universal Flash Storage) chips are swapped to a new motherboard.
- After the swap, the phone is connected to the charging cable, and this time, there is a charging current.
- Assemble the phone and trigger it to boot, which it does successfully.
2: Data Recovery
- Connect the phone to a computer and back up the important data.
3: Final Assembly
- Replace the damaged screen, battery, and housing.
- Test all functions to ensure the phone is working normally.
Conclusion
The Xiaomi Mi 8, which was severely damaged in a drop, had an unbootable motherboard likely due to internal PCB rail damage. By swapping the CPU and UFS chips to a new motherboard, the phone was successfully repaired, allowing for data recovery and restoring full functionality.
