Released on September 19, 2014, this 4.7" screen iPhone is the smaller version of the iPhone 6 Plus. Identifiable by the model numbers A1549, A1586, and A1589.

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iPhone 6 wont turn on

Good afternoon.

Shortly the story of the phone. Iphone 6 suddenly wont turn on & wont be recognized by the PC. Phone dont have any kind of water-damage. The phone died when i was reading news.

With power supply on 3,8 V and when pressing power button - amps are like 0,06-0,07.

With charger the amps are like 0,5 A and then suddenly 0 Amp & then reapeats back to 0,5 etc.

Any ideas, where to start looking for?

Beantwoord! View the answer Dit probleem heb ik ook

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UPDATE!

So i have checked the power rails and you were correct Minho. The mentioned line is not shorted. The weird thing is phone tries to boot draw like 0,1 A and then back 0 and repeat's. 1 time it actually went up to 0,25 Amps.

I write up the result of measuring.

PP_VCC_MAIN - 3,8V

PP_BAT_VCC - 3,8 V

PP1V5_USB - OK

Power rails : First result is in diode mode and then in volts. All the voltages drops and rise up then.

PP_CPU - No short (170) ; 0,85V

PP_GPU - No short (097) ;

PP_1V8_SDRAM - No short (937) ; 1,8V then 1,19V and then 0 and repeats.

PP1V2_SDRAM - No short (438); 1,2 V

PP_VAR_SOC- No short (315) ; 0,91 V

PP_0v95_FIXED_SOC - No short (193) ; 0,95V

PP_3V0_Tristar - No short (402) ; 3V

PP3V0_NAND - No short (420) ; 3V

PP1V8_Always - No short

PP1V0 - No short (1305) ; 1V

PP3v0_Mesa - 3V

PP1v8_VA_L19_L67 - 1,8V

PP3v0_PROX_ALS - 3V

PP3v0_PROX_IRLED - 2,99V

What to check more to determine what's causing the resetting ?

Also weird thing the power button is attached but still does not turn it on. Only by shorting the 2 pin's works.

And also weird thing. With power supply on 3,8V - it draws 0,1 A but like with 3V - it draws 0,15 A.Why so?

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Gekozen oplossing

When dealing with a “dead” phone, there is no "silver-bullet" solution. You have to probe the board to get a better understanding of what is working properly and what is not. It may be a simple solution or a complex one. Sometimes we see a visibly blown cap, replace and all is well. Other times, everything looks perfect yet the phone won't boot. In other words, use your brain :>).

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 device
  • PP1V0 – 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 Amp
  • PP3V0_PROX_ALS – Supplies the Proximity and Ambient Light Sensor
  • PP3V0_PROX_IRLED – Supplies the Infrared LED of the Proximity sensor
  • PP3V0_IMU – Supplies the Compass
  • PP3V3_USB – Supplies the USB functionality of the SoC
  • PP3V3_ACC – Supplies power to any accessory connected to the Lightning Port via the Tristar IC. (This line is only "on" for a very short period of time so you only need to worry about shorts, not voltage)

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.

Update (05/09/2018)

Update!

PP_BATT_VCC - No short (checked on TP2545 - 3,8 V)

PP_VCC_MAIN - No short (Checked on C5202_RF - 3,8 V)

PP5V0_USB - No short (checked on J1817 - But not showing volts without dock connector?)

Power rails :

PP_CPU - Not stable 0,8V then 0,4 and up again.

PP_GPU - 0V (Checked capacitor's C1226:C1210 both end's grounded - So this line is shorted right?)

Same jumping was on these lines PP1V8_SDRAM & PP1V2_SDRAM.

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Commentaar:

Hi Minho. Thanks for the reply. But could you help a bit understanding of this section:

"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."

When i connect the DC power supply with 3,8 V - I wont need to turn the phone on ? To ensure that the voltage drops constatly or ?

door

Something is causing your phone to go from a reset mode to a non-reset mode. If you probe RESET_1V8_L, you will probably see the same phenomenon. These are not easy to solve as there is a bit of a catch-22 going on. Something is pulling down the system but it tries to restart.

Double check your PP_GPU. It is low resistance so it will make most meters beep but look at the actual reading. It should be 20-80 Ohms. If you are seeing something in the low, single Ohm range, then there may be a short on that line.

door

So i should check these lines what you mentioned ?

Hi Tomas. I would check the following:

Verify the resistor on the 45_LCM_REXT line to insure it meets specifications. This resistor is responsible for properly biasing the MIPI/DSI interface circuit.

Verify that R0206 is within specifications and that C0201 is not shorted. R0206 pulls up the RESET_1V8_L line to 1.8V.

Verify the internal continuity of the RESET_1V8_L line 1.8V line by testing between TP2508 and pin C2 of Chestnut. This will require that you remove U1501. If this line is broken, then you will need to run a jumper.

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Yes, that was the point of linking in my previous answer to a similar question.

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