Repair steps: iPhone 7P can't turn on
We received an iPhone 7P from the customer, and the fault description is that the phone cannot be turned on. How to fix? Please read below.
First, plug in the iphone power cable to measure the charging current. The input current is about 200 mA and still jumps. Connect to your computer and it won't open.
Next, remove the machine and connect the DC power supply and we found no current. There is no leakage on the front side, triggering a large current, reaching 1.9A. Then, it is easy to spray the rosin onto the power supply and the current appears.
When we saw this, we all feel frustrated. Does the main power supply has failed? We decide to open the circuit diagram. And open the hot spot, we find there is the NAND flash power supply. Test whether there is a short circuit in the NAND flash! Without surprise, the fault from here after testing with digital multimeter. Because the 6s machine has many problems, what can we refered to is NAND flash at first. Click a few points, we thought this point probably have fault, and measured it, it is the fault one.
The next step is simple. Use the iphone Scraper to remove the power supply capacitors around the NAND flash. Plaster on rosin, adjust the current meter to 3V and operate directly.
We found this capacitor shorted and use the crowbar to open it.
Then test it ,we found that there is no short circuit.Turn on and test the battery's electric light is shine. Put it on the activation board and add some power, then turn it on again.
There should be no problem here, we should notice: it is not necessarily that the hot one fault. I think that many people will move the main power supply when repair this iphone. But my advice is to check the circuit diagram with WUXINJI Dongle to test if the power supply is short-circuited. Such short-circuits outside often occur. Many of the first pictures are short-circuited by the main power supply itself.
First, plug in the iphone power cable to measure the charging current. The input current is about 200 mA and still jumps. Connect to your computer and it won't open.
Next, remove the machine and connect the DC power supply and we found no current. There is no leakage on the front side, triggering a large current, reaching 1.9A. Then, it is easy to spray the rosin onto the power supply and the current appears.
When we saw this, we all feel frustrated. Does the main power supply has failed? We decide to open the circuit diagram. And open the hot spot, we find there is the NAND flash power supply. Test whether there is a short circuit in the NAND flash! Without surprise, the fault from here after testing with digital multimeter. Because the 6s machine has many problems, what can we refered to is NAND flash at first. Click a few points, we thought this point probably have fault, and measured it, it is the fault one.
The next step is simple. Use the iphone Scraper to remove the power supply capacitors around the NAND flash. Plaster on rosin, adjust the current meter to 3V and operate directly.
We found this capacitor shorted and use the crowbar to open it.
Then test it ,we found that there is no short circuit.Turn on and test the battery's electric light is shine. Put it on the activation board and add some power, then turn it on again.
There should be no problem here, we should notice: it is not necessarily that the hot one fault. I think that many people will move the main power supply when repair this iphone. But my advice is to check the circuit diagram with WUXINJI Dongle to test if the power supply is short-circuited. Such short-circuits outside often occur. Many of the first pictures are short-circuited by the main power supply itself.
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