iPhone 6s Water Damage

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iPhone 6s

Дата выхода 25 сентября 2015 г. Модель A1688 / A1633. Ремонт данного устройства схож с предыдущими моделями, требующий отвертки и инструменты для вскрытия. Доступен в версиях GSM или CDMA; с 16, 64 или 128 ГБ памяти; в цветах: Серебристый, Золотой, «Серый космос» и «Розовое золото».

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Glen Fitchett @glenpy

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Опубликовано: 10 апр 2018 г.

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iPhone 6s Water Damage

Hi,

Ive got an iPhone 6s with previous water damage. Ive removed all the shields and carried out a full clean inc Ultra sonic. Ive tested VCC_Main , BATT_VCC & PP_5V0_USB with the board unpowered and powered no obvious shorts or low resistance readings. Ive tested The Various PMIC output Rails PP_GPU, PP_CPU, PP_SOC, PP_3V0_MESA etc all seem ok. When i connect the logic board to DCPS with voltage set to 4.2v the logic board doesn't draw any amps until i short pin 2 on the connector, the board then seems to boot normally with a steady increase in amp draw for about 3 seconds then the amp draw becomes erratic jumping from as low as .003a to as high as 1.03a it then fluctuates between these values. With a screen connected i get no image & no backlight.

Any ideas??

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Minho @refectio

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You say you checked "the various" PMIC outputs. Did you check them all or only a few of them. That does make a difference from a troubleshooting perspective.

If you have and they all checked out okay, then I would check the outputs from U_PMU_RF as well. Problems with the BB PMU can also cause bootup issues. If everything looks okay, I focus on the charging circuit and make sure it functions properly and then replace Tristar to see if that helps. Report back!

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Minho thanks for your reply,

I checked the following PMIC outputs & got the following readings;

PP_1V1_SDRAM - 1.1v PP_3V3_USB - 3.2v PP_3V0_TRISTAR - 3v

PP_1V8_SDRAM - 1.8v PP_1V8_VA - 1.8v PP_0V8_Owl - 0.8v

PP_3V0_NAND - 3v PP_3V0_Prox_Als - 3v PP_0V9_NAND - .9v

PP_3V0_Prox - 3v PP_1V8_Always - 1.8v PP_3V0_MESA - 3v

PP_1V2 - 1.2v PP_1V8_MESA - 1.8v PP_Fixed - 0.9v

PP_CPU_SRAM - 0.8v PP_SOC - 0.8v PP_CPU -0.9v

PP_VCC_MAIN - 4.4v

I found a couple of rails that were showing no voltage, i assumed this was perhaps because the phone wasn't booting up.?

PP_GPU_SRAM

PP_GPU

PP_3V3_ACC

PMU LDO 8

I will have a look at the outputs from U_BB_RF when i get a chance after work tomorrow.... i refuse to be beaten by an iPhone!!

Many thanks.

10 апр 2018 г. из Glen Fitchett

Certain iPhones will beat you, unfortunately.

PP_GPU only activates when the display is required. So you need to either push a power button or connect the dock to a charger or iTunes. That activates the display and then you can measure PP_GPU.

PP3V3_ACC is on for only a fraction of a second and isn't required or necessary to a properly booting phone. You'll want to follow up on PP_1V8_LDO8 though as it feeds the BB.

11 апр 2018 г. из Minho

Evening Minho Thanks for the info,

Ive Managed to check the outputs from U_PMU_RF and all the readings are 0v. It seems like the BB & BB PMU or not receiving power. No lines appear to be shorted and resistance readings around BB are around 90ohms. Ive replaced BB_PMU with a known good and still no voltage on the output side. Im getting Vcc Main & Vcc Batt voltage at the switches before BB_PMU. Could this be CPU related? When Connected to the DCPS and booted it now pulls a constant 0.06a.

Any ideas?

Many thanks

13 апр 2018 г. из Glen Fitchett

So all of the U_PMU_RF outputs are at 0V and none of them are shorted to ground? Can you compare diode measurements of these outputs to known-good?

Assuming everything looks okay, I would check out the reset signals on U_PMU_RF such as AP_TO_BBPMU_RADIO_ON_L, PMU_TO_BBPMU_RESET_L and PS_HOLD_PMIC. Also check the reset output from U_PMU_RF (PMIC_RESOUT_L) to see if it corresponds to the inputs or the state of the IC.

13 апр 2018 г. из Minho

Yeah they all measured 0v. I'll comprise some diode measurements from a known good board and then compare and see if anything obvious shows up. If not i'll check the reset signals as you've suggested and report back!

Cheers buddy.

13 апр 2018 г. из Glen Fitchett

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Minho thanks for your reply,

I checked the following PMIC outputs & got the following readings;

PP_1V1_SDRAM - 1.1v PP_3V3_USB - 3.2v PP_3V0_TRISTAR - 3v

PP_1V8_SDRAM - 1.8v PP_1V8_VA - 1.8v PP_0V8_Owl - 0.8v

PP_3V0_NAND - 3v PP_3V0_Prox_Als - 3v PP_0V9_NAND - .9v

PP_3V0_Prox - 3v PP_1V8_Always - 1.8v PP_3V0_MESA - 3v

PP_1V2 - 1.2v PP_1V8_MESA - 1.8v PP_Fixed - 0.9v

PP_CPU_SRAM - 0.8v PP_SOC - 0.8v PP_CPU -0.9v

PP_VCC_MAIN - 4.4v

I found a couple of rails that were showing no voltage, i assumed this was perhaps because the phone wasn't booting up.?

PP_GPU_SRAM

PP_GPU

PP_3V3_ACC

PMU LDO 8

I will have a look at the outputs from U_BB_RF when i get a chance after work tomorrow.... i refuse to be beaten by an iPhone!!

Many thanks. — Glen Fitchett
Certain iPhones will beat you, unfortunately.

PP_GPU only activates when the display is required. So you need to either push a power button or connect the dock to a charger or iTunes. That activates the display and then you can measure PP_GPU.

PP3V3_ACC is on for only a fraction of a second and isn't required or necessary to a properly booting phone. You'll want to follow up on PP_1V8_LDO8 though as it feeds the BB. — Minho
Evening Minho Thanks for the info,

Ive Managed to check the outputs from U_PMU_RF and all the readings are 0v. It seems like the BB & BB PMU or not receiving power. No lines appear to be shorted and resistance readings around BB are around 90ohms. Ive replaced BB_PMU with a known good and still no voltage on the output side. Im getting Vcc Main & Vcc Batt voltage at the switches before BB_PMU. Could this be CPU related? When Connected to the DCPS and booted it now pulls a constant 0.06a.

Any ideas?

Many thanks — Glen Fitchett
So all of the U_PMU_RF outputs are at 0V and none of them are shorted to ground? Can you compare diode measurements of these outputs to known-good?

Assuming everything looks okay, I would check out the reset signals on U_PMU_RF such as AP_TO_BBPMU_RADIO_ON_L, PMU_TO_BBPMU_RESET_L and PS_HOLD_PMIC. Also check the reset output from U_PMU_RF (PMIC_RESOUT_L) to see if it corresponds to the inputs or the state of the IC. — Minho
Yeah they all measured 0v. I'll comprise some diode measurements from a known good board and then compare and see if anything obvious shows up. If not i'll check the reset signals as you've suggested and report back!

Cheers buddy. — Glen Fitchett

iPhone 6s

iPhone 6s Water Damage

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