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Released September 16, 2016. Model 1660, 1778 Available as GSM or CDMA / 32, 128 or 256 GB / Rose gold, gold, silver, black, and jet black.

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iPhone 7 no Power Up-No Short!

Hello All

i Have an iPhone 7 that No Power Up

I testet its Logic board for any short but it has no Short

I test all the voltages they was ok

when I connect it to charger its draw 0.41 miliAmp but its not detected by computer, SO the problem isn’t the NAND!

i try to use DC power,when i press the PWR Button it draw 0.06, 0.8, 0.11 and repeat this circle….,No image, No heat…

can anyone help pleasse?and sorry for my bad english.

Answered! View the answer I have this problem too

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Hi I have seen this a few times. If the DCPS is going back to 0.00 then it sounds as if one of the RESET lines is being triggered. These are IC’s that can cause a reset to the main PMU e.g. TRISTAR_TO_PMU_HOST_RESET. It could be many things but I have seen this caused by TRISTAR, failing that it may need a CPU reball. Has it had a drop or anything? I would also double check for shorts on the NAND power.

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Hi thank you for your Guide,i Reballed the Cpu but nothign change,i will try the Tristar and Say the Result,Thank you bro

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I test it,nothing change,I changed the Tristar but nothing....

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I have a phone which was run over, but the board looks to good condition. No obvious bend in it.

  • I trigger the device to boot via the dock and hooking up a USB cable
  • The device shows some current being drawn and the pattern repeats, between each pull it drops to 0A. The approximate values are 0.8A, 0.6A, 0.3A, 0.2A, 0.1A
  • Additionally, the USB meter shows 0.00A throughout. On a rare occasion it goes to 0.40A and then 0A

I started to learn the various power lines on the board and checked a few.

  • VDD_MAIN pulls approximately what the DCPS suppliers i.e. 4.1V
  • VDD_BOOST appears ok as well without any short.
  • The above power lines, per my understanding are pre the PMIC. On this output side, it supplies the NAND, SDRAM, CPU/GPU (SOC) with 1.8V.
  • When checking the voltages, I don't see anything on the CPU/SOC/GPU. They are all 0.0V (PP_CPU_VAR, PP1V1_SDRAM, PP0V9_SOC_FIXED), but I do see a small voltage spike on the NAND line PP3V0_NAND. It seems to be relative to the current my DCPS pulls. The most I see is 0.08V, much lower than the expected 0.85V???

Can this be caused by a bad Tristar? Looks like a reset line may be pulled between each current draw.

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Hi kapsolas thank you for sharing information, finally I found out That the problem is related to CPU coil power line, Check them all, Good luck!

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Mohamad Amin will be eternally grateful.
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