1. Is there an iCloud activation lock?
When buying a second-hand iPhone, you should confirm whether there is an iCloud activation lock (that is, an ID lock) on the iPhone through Apple official website. If there is an activation lock, first, it is impossible to confirm whether the seller is the owner himself, and second, the iPhone may be directly locked remotely one day and completely unusable.
Second, the query serial number
Confirm some important information of iPhone serial number, such as activation time, remaining warranty period, etc., through third-party tools such as Apple official website, fruit powder query and Ann Bunny. The serial number of the iPhone is determined by the motherboard, but scammers in the market may tamper with the serial number, so we need to do the third step.
Third, DFU brush machine?
After getting a second-hand iPhone, it is recommended to use DFU mode to brush the machine. Whether it is a demon machine (that is, changing the baseband, IMEI and serial number of the refurbished machine through technical means is equivalent to one file with two mobile phones), we will know after inspection. During DFU recovery, the demon machine may have the following conditions:
1. The error code cannot be recovered.
2. It cannot be activated after brushing.
3. Being in the "white apple" interface for a long time during brushing can't continue the next step.
Note: the brush machine itself has unpredictable risks. So before choosing a brush machine, you must carefully consider whether it is necessary to brush the machine. If you are not sure, please call a professional. In addition, you should check the parallel plane and DFU before GSX to prevent being locked. But for most novices, DFU is still difficult to get started, so there is a direct and simple method to erase all the contents, restore the factory settings, and then check the serial number. Most information, such as shell color, memory, model, etc. , can match, so there is no problem. This method is effective for most demon machines.
Fourth, hardware detection.
Finally, we need to test the hardware of the second-hand iPhone. First of all, it is necessary to judge whether the color, appearance and color of the machine are consistent with the serial number query results, and check whether the handle of the iPhone is as good as the genuine one, and whether the mesh cover of the receiver and speaker is woven. Then check whether the touch of the power button, volume button, mute button and Home button is sensitive, whether the feedback is obvious but not stiff, and check whether the camera has dust or cracks.
Then, we need to open it for the next test:
1, screen checking method:? Download some pure white (open the mailbox with a pure white interface), pure black (stock market or watch application can also make do), pure green and pure red wallpaper, and adjust the brightness to see if there is uneven backlight and bad light spots on the mobile phone, tilt the viewing angle and see if there is obvious light leakage at the edge.
2. Is the touch ID normal? Whether the fingerprint identification function is smooth and sensitive can be known by trying to enter it once and unlocking it many times.
3. Is Wi-Fi normal? Detect WiFi? Whether the connection is normal and stable, signal strength, etc.
4. Is the gyroscope normal? Open the native compass program and give it a try.
5. Is camera focusing available? You can try taking pictures, macro, etc. IPhone 6 has phase focusing, and you can also use your palm to see if the camera can quickly and automatically switch between short distance and long distance.
6. Is the earphone normal? Insert headphones as smoothly as possible. If the headphone jack doesn't work, the motherboard may be damaged.
7. Is the distance sensor normal? When making a phone call, test whether it will turn off the screen and be sensitive once it is covered near the receiver. Just try it.
8、? Is the flash normal? Turn on the camera, switch to video recording mode, and choose to turn on the flash. Pay attention to whether some models of cold and warm LED flash work normally at the same time, and you will know if you give it a try.
9. Is Bluetooth normal? IPhone can only match other Bluetooth devices, and cannot search other iphones. Take a Bluetooth headset and connect it. Just try it.
10. Is the microphone normal? Open the voice memo program that comes with the system, and you will know it as soon as you record it.
1 1、? Is the vibration function normal? Tap the mute button on the side of the phone and try it.
12. Is there a network lock? Turn off data roaming in cellular data, and the built-in card pasting machine may not be able to access the Internet after it is turned off.
13. Did you disassemble the machine? This needs to be disassembled to judge, mainly depending on whether the internal test paper is in good condition and whether there are obvious traces of motherboard maintenance or "flying line" welding. You can also simply judge from the appearance, and carefully observe whether the gap of the face shell is tight, whether there are prying marks and whether the screws are twisted.
The above are the problems that need to be paid attention to when buying a second-hand iPhone, please adopt it ~