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iPhone 5s Apple flashes and then board draws a steady 0.2A for a short

A wet 5S came in and I washed the board in an ultrasonic cleaner. All it does now is flash the Apple logo and draw a steady 0.2A for a few seconds and then shuts off.

Is there something in particular that I should be looking for (the board is visually fine) or do I really need to start testing components?

Any help would be greatly appreciated and thanks in advance.

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Realistically, if this phone was water damaged, you’d be lucky if a modular component would solve the issue. You still need to try though but once it’s clear it’s not a modular issue, then you’ll need to start probing the board.

If you suspect a logic board issue, 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.

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, PP1V8_SDRAM, PP1V2_SDRAM, PP_VAR_SOC, PP0V95_FIXED_SOC, PP3V0_Tristar, PP3V0_NAND, PP1V8_ALWAYS and PP1V0.
  • The PMIC also generates, what I would consider secondary, yet still important voltage rails for the following sub-systems: PP3V0_MESA, PP1V8_VA_L19_L67, PP3V0_PROX_ALS, PP3V0_PROX_IRLED, PP3V0_IMU, PP3V3_USB and PP3V3_ACC

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Start testing with / without components for example, boot with:

  • Front camera unplugged
  • Replacement battery, try another charging port plug in temporarily
  • Boot with DC Bench power supply with appropriate iPhone battery connector adaptor for power supply.

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Yea that’s the first things I do with a wet phone after I wash the board. I plug it into all good parts and see what it does. After all that it was still dead and I found a few bad capacitors and a short on the board fixed that and then they called me. I warn people it takes awhile and they did not give me the whole story on the phone but apparently it isn’t their’s and they need it to work by the end of the week so I was just hoping someone would maybe have a quick ideas as to if it was a particular chip that needed to be replaced.

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I do try to leave components off and when I unplugged the LCD the current dropped and seemed like it wanted to work by the current fluctuations. Not sure if that tells you anything

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