Why iPhone 6S doesn't boot successfully after pressing the power button? We tried recharge and replace the screen and battery, but the iPhone 6S still doesn't boot. This iPhone 6S was dropped before, so we suspected the iPhone logic board is damaged. We need to fix the damaged iPhone logic board, so the iPhone 6S can boot smoothly.
Disassemble the iPhone 6S by phone opening tools, remove the iPhone display assembly, disconnect the iPhone battery, and then remove the iPhone logic board.
Measure the iPhone logic board by DPS DC power supply, the iPhone current doesn't display, and the there is no obvious short-circuit phenomenon on the iPhone logic board.
Use tweezers to short connect the boot pin to turn on the iPhone 6S, after booting; we can see that the current is larger than normal value, which means there is a short-circuited phenomenon on the iPhone motherboard.
We need to find the short-circuit component. Use digital multimeter to measure the diode data for the power supply of each circuit on the iPhone motherboard, it's found that the diode data of the PP_CPU voltage is 0.002, which is abnormal.
Log in to the ZXW online account to check iPhone 6S schematic diagram, we can see that there are many components that connect to the PP_CPU voltage, now we need to use rosin method to confirm the short-circuit part.
Stick the QUICK TS1200A soldering iron head to the rosin, and then evenly smoke the rosin on the surface of each component. Short connect the boot pin to turn on the iPhone 6S, we found the rosin on a capacitor next to the iPhone CPU is melted fast.
According to the iPhone schematic diagram, we know this capacitor is C2006. Replace this capacitor with a new one, and then measure the iPhone logic board again, now the measured value is normal.
Next install the iPhone 6S, press the power button, the iPhone is turned on properly.
After testing, all of the iPhone functions are normal. The iPhone 6S has been fixed!
Disassemble the iPhone 6S by phone opening tools, remove the iPhone display assembly, disconnect the iPhone battery, and then remove the iPhone logic board.
Measure the iPhone logic board by DPS DC power supply, the iPhone current doesn't display, and the there is no obvious short-circuit phenomenon on the iPhone logic board.
Use tweezers to short connect the boot pin to turn on the iPhone 6S, after booting; we can see that the current is larger than normal value, which means there is a short-circuited phenomenon on the iPhone motherboard.
We need to find the short-circuit component. Use digital multimeter to measure the diode data for the power supply of each circuit on the iPhone motherboard, it's found that the diode data of the PP_CPU voltage is 0.002, which is abnormal.
Log in to the ZXW online account to check iPhone 6S schematic diagram, we can see that there are many components that connect to the PP_CPU voltage, now we need to use rosin method to confirm the short-circuit part.
Stick the QUICK TS1200A soldering iron head to the rosin, and then evenly smoke the rosin on the surface of each component. Short connect the boot pin to turn on the iPhone 6S, we found the rosin on a capacitor next to the iPhone CPU is melted fast.
According to the iPhone schematic diagram, we know this capacitor is C2006. Replace this capacitor with a new one, and then measure the iPhone logic board again, now the measured value is normal.
Next install the iPhone 6S, press the power button, the iPhone is turned on properly.
After testing, all of the iPhone functions are normal. The iPhone 6S has been fixed!
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