HUAWEI Mate 40 Pro water damage and the funny thing is the phone was dropped into the water by the dog.
The situation is similar to the following
Defect Phenomenon
Receiving this phone then disassemble to check the parts and motherboard inside.
But after disassembling the phone, the motherboard inside looks fine, just like the OEM New.
Check the motherboard carefully, there is no water damage sign or any other abnormal like deformation, part missing, etc. Check the parts inside, everything also looks fine.
Measure the diode values on the connectors, also OK.
Connect the motherboard with the DC power supply, there is no current leakage either.
Trigger the power button to start up, and the board can be booted normally.
Is it possible the repair center made the wrong judgment?
Let’s assemble the board and parts, then connect with the DC power supply machine and turn on the device to test again. Once connected with the DC power supply, there is a 40-50mA current leakage. And the board cannot be booted again.
This means the motherboard is OK, the no boot is caused by the parts damage.
Then let’s connect the connectors one by one to test, and when testing with the DOCK flex cable there is a 40mA current leakage.
The dock flex cable is responsible for the charging and SIM card recognization.
After removing the plastic shielding cover, as we can see the connector under it gets corrosive.
Take out the little board, a large part of the board gets seriously water damaged and corrosive.
The deal with the corrosives on the little board
For the connectors
- heat with the hot air gun to remove them
- clean the pads on the PCB board with soldering iron and solder paste
- clean the motherboard with PCB cleaner
- solder back the connectors
For the components and chips under the shielding cover
- heat with the hot air gun to remove the shielding cover first
- resolder the chips which look not good
- solder back the metal shielding cover
For the DOCK flex cable
You can purchase a new one or resolder the connector by the below steps
- Heat it up with the hot air gun slightly to take it off without damage
- Clean the oxidized pads on the flex cable with soldering iron and tin paste
- Clean the connector with PCB cleaner then solder it back with the soldering iron, ensure each pad are well connected
After that, assemble the phone to test, the phone can boot normally.
And all the functions like the display, touch, camera, Wi-Fi, Baseband, etc. are OK.
>>> Go to REWA Android Repair Course to learn more.
