Solved Iphone 6S Died On Update What Should I Check Iphone 6S

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I everyone. I already asked this question before, but got no real answer to my problem. My iPhone 6s just died while updating, just turned off and didn’t turn back on since then. Yes, I have tried to put it in dfu mode and connected to iTunes, tried to hard reset it (the phone won’t display anything at all). I cracked it open and checked if the battery or charging port were dead, they are both fine. What should I check next? Thanks!

Once you get serious about micro-soldering repairs, having ZXW is a must and a huge time saver. In the meantime, get the schematics and pads .pcb files and start with that. Regarding your problem, so many things can be the root cause of a dead phone that it’s hard to say remotely what it is. The fact that it happened during an update can also be coincidental. So here is what I recommend you try with this phone. It will help you understand the schematic and how the phone is “put together” electronically speaking. It’s not the fastest way to find the problem but then again, with discipline and practice, it will guide you well. The NetNames below are for the iPhone 6 and they differ slightly on the iPhone 6S but it is close enough you should be able to figure eveything out. If you have access to a USB Ammeter, you could use that to determine if the phone is really drawing current or not. When dealing with a “dead” phone, you have to start at the beginning and check PP_BATT_VCC, PP_VCC_MAIN and PP5V0_USB. I would start by checking to see if those rails are shorted to ground. If one of these rails is shorted to ground, then you will need to identify what is causing the short. It could be a bad decoupling capacitor, conductive debris or defective IC that is directly supplied by those rails. If they are not shorted, then you can connect, preferably, a known-good battery (or a current limited DC power supply with the appropriate connector adapter) to see what voltage you measure. If the voltage is low or lower than the battery voltage (which you measured before plugging it in ;>), then there could be a short circuit on secondary subsystem that is causing the battery or DCPS to be current-limited. If you are measuring the proper voltage, then you move onto the PMIC and check the voltage rails it generates. The PMIC generates ~15 voltage rails. They are all important (for obvious reasons) but the ones to check first are as follows: PP_CPU & PP_GPU – These rails supply the CPU & GPU. They are low resistance rails so they may “beep” when you test them on your multimeter in continuity mode. It’s important to look at the reading and not focus just on the beep. You will typically measure something around 20-100 Ohms on these lines.PP1V8_SDRAM & PP1V2_SDRAM – These rails supply the SDRAM (which is sandwiched with the SoC/CPU).PP_VAR_SOC & PP0V95_FIXED_SOC – These rails supply the rest of the System on a Chip. What we commonly refer to as the CPU is actually a SoC.PP3V0_Tristar & PP3V0_NAND – These rails supply Tristar & the NAND chip.PP1V8_ALWAYS – This is an “always-on” voltage rail that is used for the bootstrapping of the devicePP1V0 – Supplies the High Speed Digital Communications via the SoC The PMIC also generates, what I would consider secondary, yet still important voltage rails for the following sub-systems: PP3V0_MESA – Supplies the Home Button TouchID subsystem.PP1V8_VA_L19_L67 – Supplies the Audio Codec and Speaker AmpPP3V0_PROX_ALS – Supplies the Proximity and Ambient Light SensorPP3V0_PROX_IRLED – Supplies the Infrared LED of the Proximity sensorPP3V0_IMU – Supplies the CompassPP3V3_USB – Supplies the USB functionality of the SoCPP3V3_ACC – Supplies power to any accessory connected to the Lightning Port via the Tristar IC Once again, you should start with measuring the resistance while unpowered to limit any potential damage of excessive current going through the logic board. If there are shorts, do as above to identify any faulty components. If there is no apparent short or you can’t find the source of a short, you can connect the battery and look for hotspots (you can use the freeze-spray or IPA method). Do this with caution to avoid additional damage to the logic board. The whole point of this exercise is to better understand the patient. A doctor can’t diagnose until they learn human anatomy.

Take it to someone that does microsoldering for evaluation.