We are going to fix an iPhone 6 device today, the iPhone 6 signal keeps searching state after booting, there is no baseband in local setting, and no series number shows up when dialing *#06# serial number.
We find the iPhone 6 LCD(has been replaced once, this kind of situation is preliminary determined for baseband CPU false welding, it is relatively common situation on iPhone 6 and iPhone 6P. Anyway we need to test first!
From the simple start, measuring the single iPhone 6 motherboard baseband power supply, first measure the main power supply 4.2V (C3221_RF).
Then testing basebnd output voltage of power supply on C3262, C3252, C3259, C3256, if there is a voltage without first measuring resistance, if resistance is normal, then replace normal baseband power test; if four of them are simultaneously without resistance, then you need to reinstall the baseband CPU. There is a small glass tube base strip above the baseband power supply, it must be noticed when the main board is disassembled, if it gets damaged, the iPhone 6 will not be repaired.
Before the iPhone 6 CPU is removed, we must deal with the shielding cover carefully. We need to cut it off with professional cell phone repair scissors. This is relatively safe. The shielding factory is very strong in welding, and the risk of heating and blowing is relatively large.
The baseband CPU can be mounted on the fan to avoid heating IC. It doesn't matter if you see some empty solder points. It takes two parts to solder jumper wire on the pad: U1 and V1 pin.
It may be okay to see two points on the naked eye, but under a Trinocular Stereo Microscope, it will be found that the two points are at the top of the layer, and the line is very thin. Sometimes there will be baseband faults when the line is disconnected. For the sake of insurance, solder jumper wire first.
The small U is thicker. When do CPU reballing, you can cut out a small square on the paper towel and put the small U in it. After installing the baseband CPU, you can first test the C3402_RF to determine whether whether the baseband CPU is installed ok.
Now both baseband and signal are tested normal.
If you need more cell phone repair knowledge please visit on www.vipfixphone. com
From the simple start, measuring the single iPhone 6 motherboard baseband power supply, first measure the main power supply 4.2V (C3221_RF).
Then testing basebnd output voltage of power supply on C3262, C3252, C3259, C3256, if there is a voltage without first measuring resistance, if resistance is normal, then replace normal baseband power test; if four of them are simultaneously without resistance, then you need to reinstall the baseband CPU. There is a small glass tube base strip above the baseband power supply, it must be noticed when the main board is disassembled, if it gets damaged, the iPhone 6 will not be repaired.
Before the iPhone 6 CPU is removed, we must deal with the shielding cover carefully. We need to cut it off with professional cell phone repair scissors. This is relatively safe. The shielding factory is very strong in welding, and the risk of heating and blowing is relatively large.
The baseband CPU can be mounted on the fan to avoid heating IC. It doesn't matter if you see some empty solder points. It takes two parts to solder jumper wire on the pad: U1 and V1 pin.
It may be okay to see two points on the naked eye, but under a Trinocular Stereo Microscope, it will be found that the two points are at the top of the layer, and the line is very thin. Sometimes there will be baseband faults when the line is disconnected. For the sake of insurance, solder jumper wire first.
The small U is thicker. When do CPU reballing, you can cut out a small square on the paper towel and put the small U in it. After installing the baseband CPU, you can first test the C3402_RF to determine whether whether the baseband CPU is installed ok.
Now both baseband and signal are tested normal.
If you need more cell phone repair knowledge please visit on www.vipfixphone. com
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