In this blog, we will be going the Apple 7P Error 4013 fault repair ideas and testing process. These symptoms include boot white apple logo, repeated restart, can't enter the system normally, and the machine is giving off error 4013 code.
The points that cause the failures
1.The damage of the front camera will cause the white apple to restart without entering the system
2. Baseband power supply damage or virtual soldering will cause the white apple to restart without entering the system.
3.The crystals oscillator next to the baseband power supply or the solder joint will also cause the white apple to restart.
4.The baseband power supply output 5 power supply, S1, S2, S3, S4, S5 voltage, one of which has a short circuit will also cause the white apple to restart.
5.The baseband CPU itself is soldered or damaged, which cause the white apple to restart.
6.The baseband power supply and the baseband PU board bottom have a point that causes the baseband power supply to not work properly. The output voltage or the baseband CPU lacks a certain condition and does not work.
The maintenance inspection process:
1. First, determine the cause of the fault is caused by the logic board or parts. If you cannot replace parts to test the fault and boot to see if it's normal. Then just go straight for the logic board, but best to replace the front camera and see if it boots normal first.
2. Static detection of the fault of the mobile phone motherboard, determine the fault on the motherboard, lock the fault in the baseband power supply and the baseband CPU related circuits, need to detect the judgment point.
Special Note: Focus on the four coupling capacitors (C0815, C0816, C0817, C0818) of the PCIE2 bus between the main CPU and the baseband CPU. If one of them is soldered or dropped, the fault will be caused.
First observe under the microscope, the baseband power supply itself and the nearby and baseband CPU itself and nearby there are traces of water, traces of being repaired, corrosion, peeled off, or displaced. Pay attention to the chips that others have soldered. It is important to check whether there is soldering.
Use the multimeter diode to measure the key test points, and focus on measuring the ground resistance of the five-way power supply inductor or the connected filter capacitor of S1, S2, S3, S4, S5 to determine whether there is a short circuit to the ground or s resistance value low. If one of the paths is the shorted circuit, it is necessary to eliminate the short circuit and find the cause of the short circuit. It may be damaged. Usually, if S1 and S5 are shorted to ground to zero, most of them are shorted by baseband CPU itself;otherS2, S3 and S4 shorted are mostly filter capacitors or baseband power supply before removing the filter capacitor and connected components.
Power up test each voltage. If the ground resistance of S1, S2, S3, S4, S5 and 5 power supply inductors is normal under static conditions, it means that there is no short circuit, you need to connect the power supply, and start the test to judge the 5 power supply inductance. Is there a certain voltage output or no 19.2 crystals oscillator?
Note: S1, S2, S3, S4, S5, 5 power supply of the baseband CPU, there is no voltage output when the power supply is standby, and it needs to be turned on and after the main power chip works normally, after the working conditions of the CPU are satisfied, after reading, the baseband CPU will output the voltage and the output voltage may not be instant.
Repeatedly restart the Apple phone, the measurement method, you can first use the multimeter to point the inductor, and then turn it on. It can usually be seen that after the three-hop current meter when the screen is just bright, the S2-S5 voltage output will be available at around 400MA. It is possible to measure the inductance of each circuit in multiple times.
If someone else has brushed the mobile phone before, the boot is in DFU mode. In this case, when the flashing screen is on the phone and the Itunes prompts the second waiting, the voltage of S2-S5 can be measured. Can not be measured once, can be measured in multiple times. The voltage of S1 usually needs to be brushed to about 80% and there be an output. If this voltage is not output, it will be reported as -1.
If it is found that the fiver power supply inductors of S1 to S5 are found, there is no voltage output. If there are no output voltages of the 5 channels, there are two reasons for this: the first one is that the baseband power supply itself is bad; the second baseband power supply is not satisfied, including the reset signal from the main CPU and the main power supply, and the turn-on signal, crystal oscillator, etc.
If there is a condition, the oscilloscope can measure whether the 19.2 crystal oscillator starts to vibrate. If there is no condition measurement waveform, it can be repaired. Check if there is a wire break between the 19.2M crystal oscillator and the baseband power chip and whether the 192.M crystal oscillator soldered. Replace the confirmed 19.2M crystal.
After confirming the crystal oscillator, you can replace a confirmed baseband power chip to eliminate the fault caused by the baseband power chip itself.
If the fault of the baseband power supply chip that is confirmed and replaced is still the same, it is necessary to check the working conditions of the baseband power supply chip. The detection method is usually to measure the resistance value of each pin of the base of the baseband power supply and focus on the following places: 1. Check the main power supply to the baseband power supply reset signal, baseband power supply 43 pin PMU_TO_BBPMU_RESET_L, through a resistor R2000 in the middle, can detect a voltage of about 1.8V when booting.
2. The main CPU gives the baseband power supply open signal, the baseband power supply 58 pin, AP_TO_BBPMU_RADIO_ON_L, the ground resistance value is about 400 ohms.
3. The clock-on signal of the baseband CPU to the baseband power supply: the turn-on signal sent by the baseband CPU to the baseband power supply. At the 56-pin of the baseband power supply, the normal ground resistance of XO_OUT_D0_EN should be about 500 ohms. If infinity, it may be baseband CPU to baseband power disconnection or baseband CPU soldering.
4. If the mobile phone is repaired or repaired, it is possible that the pin pad is dropped when the pad is processed, because the dot pattern or the resistance map shows that the ground is ignored. Focus on the S1, S2, S3, S4, S5, 5 power supply 5 modules of the main power input grounding pin; pay special attention to 102 feet (S2 voltage main power supply grounding pin), 93 feet (S5 voltage main power supply grounding Pin), there is only one ground pin. If the pad of this pin is off or soldered, it will cause the corresponding S2 or S5 power supply module to have no grounding pin and it will not work properly. This pin is a ground pin in the point bitmap view, and it is easy to be ignored that the ground pin is not affected and does not affect normal operation.
5. If the mobile phone is repaired and repaired, it is possible that the pin pad is dropped when the pad is processed, because the dot map or the resistance map is infinite and ignored. Focus on S1, S2, S3, S4, S5, 5 power supply 5 module voltage feedback pin, return from the inductor to the baseband power supply pin, this pin disconnection will cause the baseband power supply internal protection does not output voltage. Pay special attention to the voltage feedback pin of 91 pins for S2, which shows infinity on the dot map or resistance map. However, if the disconnection will cause the S2 voltage to not output normally, the other voltage feedback pins may be blocked. The value is not infinite, but if the pad is disconnected or disconnected, it will cause internal protection of the baseband power supply and will not output voltage.
Posted on: Aug. 24, 2018, 11:42 p.m.