How to fix iPhone 7 can't turn on
We received a defective iPhone 7, the customer said the iPhone was severely damaged and could not be opened.
When checking the iPhone, we found the screw post to fall off, but fortunately the motherboard was not damaged. Now we have to fix it.
First, trying to charge, we found a large current leak and continued to pass the digital multimeter test, we know that the 3V power supply is shorted. Carefully observe that the motherboard slot is bent and the short circuit may be in this position. Remove the two capacitors next to the NAND flash memory and turn on the power through the QUICK 861DW Hot Rework Station, and the phone will turn on normally.
Test function after turned on, we found no Wifi, sometimes stuck when enter the settings. When check, the Wifi clock signal R0807 end has 1.8V, the other end through the Wifi module 17 pin have no voltage, we replace the resistor, but the fault remains. Remove the iPhone Wifi IC, the soldering pad drop the point.
Originally, we plan to turn on phone without install the Wifi module, and test its function. But there is leakage when power-up, we have to apply rosin. After removing the heating capacitor and test, the setting function is normal, no longer stuck, next install the WiFi module.
After the installation, test again, WiFi appears, and the problem of stuck setting have been solved, but sometimes appeared restart. Considering that the middle position of the motherboard occues bent, the iPhone Audio IC will cause a restart phenomenon, so we have to disassemble the audio. After replanted fly line, all functions tested normal. The next step is to change the match.
Replace the iPhone fingerprint flex cable on the phone. Then install the repaired motherboard, test function after turned on, all function recovers normal, phone fault repair end.
When checking the iPhone, we found the screw post to fall off, but fortunately the motherboard was not damaged. Now we have to fix it.
First, trying to charge, we found a large current leak and continued to pass the digital multimeter test, we know that the 3V power supply is shorted. Carefully observe that the motherboard slot is bent and the short circuit may be in this position. Remove the two capacitors next to the NAND flash memory and turn on the power through the QUICK 861DW Hot Rework Station, and the phone will turn on normally.
Test function after turned on, we found no Wifi, sometimes stuck when enter the settings. When check, the Wifi clock signal R0807 end has 1.8V, the other end through the Wifi module 17 pin have no voltage, we replace the resistor, but the fault remains. Remove the iPhone Wifi IC, the soldering pad drop the point.
Originally, we plan to turn on phone without install the Wifi module, and test its function. But there is leakage when power-up, we have to apply rosin. After removing the heating capacitor and test, the setting function is normal, no longer stuck, next install the WiFi module.
After the installation, test again, WiFi appears, and the problem of stuck setting have been solved, but sometimes appeared restart. Considering that the middle position of the motherboard occues bent, the iPhone Audio IC will cause a restart phenomenon, so we have to disassemble the audio. After replanted fly line, all functions tested normal. The next step is to change the match.
Replace the iPhone fingerprint flex cable on the phone. Then install the repaired motherboard, test function after turned on, all function recovers normal, phone fault repair end.
评论
发表评论