Samsung Galaxy A70 Water Damage
Version: SM-A7050 (China, Hong Kong)
Defect Phenomenon
This device got water damaged, then cause no display and cannot boot up.
Teardown the device, then clean and dry the motherboard, phone can boot and display normally.
But when we dial the ‘112’ , pop up a window to remind “is opening the Antenna Switch”
Dial *#06#, the SN number displays normally, so the motherboard should be OK.
The issue might be caused by the sub PCB board.
Repair Process
First, check the cosmetic of the Sub PCB board, there’s a chip get corrosive.
Then clean the chip, install the motherboard, issue still unresolved.
Check the schematic, and as we can see this chip is SW9001 RF Switch
Remove the shielder with hot air gun, and after removing the chip, we can see there’s a pin get corrosive seriously. This pin connected with a capacitor, should be related with power supply.
Scratched out the corrosive pads, resolder with tin paste, then solder back the RF switch IC.
Assemble the phone to test, issue resolved.