The iPhone 7 enters into iTunes mode and reports error 4013 after reflashing by the customer, he did that because of signal problem, for this kind of fault, we need to detect the baseband first, if there is a problem in the baseband, do not reflash iPhone, or it will gets error fault (error 4013, -1 will be reported when the progress bar goes to the 60% or 80% position ).
We found there is a problem in the iPhone baseband. Since the iPhone is in iTunes data cable mode, we can't measure the voltage, so use Fluke digital multimer to check whether the resistance of each circuit of baseband power supply is normal. The test points of each circuit can be found more accurately based on the WUXINJI schematic diagram, and the corresponding components can be found on the bitmap for testing.
The resistance of baseband power PP_VSW_S4 is only 45, but the normal resistance value should be more than 500.
This circuit is connected to main power supply, base band power supply, small radio frequency and large radio frequency. The cell phone can be properly connected without taking into account the main power supply. First, the baseband power is taken down, the resistance is not correct, but i's normal after taking off the large RF resistance.
Replace the new baseband power and large RF IC, the reflash process passes smoothly. When purchasing the iPhone 7 7Plus chip replacement, repair technicians can prepare stocks for both two versions, Qualcomm is different from Intel chips.
Plug in card to test, all the functions are normal. The iPhone 7 error 4013 fault is caused by the damaged large RF itself, which leads to the short circuit of the baseband power circuit S4, resulting in the failure of the working conditions. It's common for the problems in the 7 and 7Plus baseband, if you encounter the same situation, you should first test the circuit.
Get more technical support from www.vipfixphone.com
We found there is a problem in the iPhone baseband. Since the iPhone is in iTunes data cable mode, we can't measure the voltage, so use Fluke digital multimer to check whether the resistance of each circuit of baseband power supply is normal. The test points of each circuit can be found more accurately based on the WUXINJI schematic diagram, and the corresponding components can be found on the bitmap for testing.
The resistance of baseband power PP_VSW_S4 is only 45, but the normal resistance value should be more than 500.
This circuit is connected to main power supply, base band power supply, small radio frequency and large radio frequency. The cell phone can be properly connected without taking into account the main power supply. First, the baseband power is taken down, the resistance is not correct, but i's normal after taking off the large RF resistance.
Replace the new baseband power and large RF IC, the reflash process passes smoothly. When purchasing the iPhone 7 7Plus chip replacement, repair technicians can prepare stocks for both two versions, Qualcomm is different from Intel chips.
Plug in card to test, all the functions are normal. The iPhone 7 error 4013 fault is caused by the damaged large RF itself, which leads to the short circuit of the baseband power circuit S4, resulting in the failure of the working conditions. It's common for the problems in the 7 and 7Plus baseband, if you encounter the same situation, you should first test the circuit.
Get more technical support from www.vipfixphone.com
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