iPhone 6S shows error 21, what should we do?
The customer sent us an iPhone 6S. He said that the iPhone 6S showed error 21, although the customer replaced the NAND flash, but the machine still does not work during the test. How can I solve it?
To get the iiPhone, first connect to the DPS power to power up, and set the current to 60mA, DFU current, plug in the computer to go online, and then brush, as described by the customer, the screen displays error 21 when the screen is open.
After reporting an error, the screen stays lit. After replacing the external device, the brush failure still exists. The QUICK 861DW hot air rework station was used to remove the main board and observed with a stereo zoom microscope. We found no suspicious points. Test CPU and NAND flash power, all of which have power. Since NAND flash has been moved before, it starts with NAND flash.
Disassemble the NAND flash, test resistance of pin with digital multimeter, the resistance is normal, replace a iphone NAND flash and brush machine again, which doesn't work up, error 21 still haven't resolve.
It seems that the NAND flash have no fault. According to the past fix experience, the error 21 is generally caused by NAND flash, flash memory, battery, etc. Now that the NAND flash and battery are normal, cover the lid on directly.
Finally, brush the machine, replace the original NAND flash, and activate, test function shows normal, the fault has been solved perfectly.
Tips: If you want to learn more about phone repair guides, you can check out www.vipprogrammer.com.
To get the iiPhone, first connect to the DPS power to power up, and set the current to 60mA, DFU current, plug in the computer to go online, and then brush, as described by the customer, the screen displays error 21 when the screen is open.
After reporting an error, the screen stays lit. After replacing the external device, the brush failure still exists. The QUICK 861DW hot air rework station was used to remove the main board and observed with a stereo zoom microscope. We found no suspicious points. Test CPU and NAND flash power, all of which have power. Since NAND flash has been moved before, it starts with NAND flash.
Disassemble the NAND flash, test resistance of pin with digital multimeter, the resistance is normal, replace a iphone NAND flash and brush machine again, which doesn't work up, error 21 still haven't resolve.
It seems that the NAND flash have no fault. According to the past fix experience, the error 21 is generally caused by NAND flash, flash memory, battery, etc. Now that the NAND flash and battery are normal, cover the lid on directly.
Finally, brush the machine, replace the original NAND flash, and activate, test function shows normal, the fault has been solved perfectly.
Tips: If you want to learn more about phone repair guides, you can check out www.vipprogrammer.com.
评论
发表评论