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iPhone Xr 0.03a No Power

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    penhitech
    Friendly Contributor

  • penhitech
    replied
    Hello Again,
    Sorry for the confusion, so the readings I have uploaded on my previous attachment were with Yangtze off, so I went over each pin when I removed the IC(U3300), at that same time when I measured VDD main, my readings were 0.00 on VDD Main so
    With IC U3300 (Yangtze) off :

    (1) VDD Main readings are 0.00 in any component a cap for example (C5690)
    (2) VDD_MAIN_YANGTZE readings are in my previous attachement. ( Picture on the right would have my measures on each pin, on the left are what It is supposed to be according to ZXW) and then on C3390 for example my reading is 0.00.

    Did you want me to check reading for you under a specific Ic that runs along VDD_Main?
    I took some pictures with my lousy camera, I know they're not crystal clear but that is all I got now.
    Of course, if you could recommend a good camera (Does not matter if it is expensive) then I would immediately place the order, the microscope I am using is the same one you are using, since I went to your youtube channel and grabbed it from your link description.
    Again sorry for the lousy photos resolutions, hopefully, it will help.
    Thank you.
    Attached Files
    penhitech
    Friendly Contributor
    Last edited by penhitech; 08-05-2021, 08:10 PM.

    Leave a comment:

  • Jessa_the_Professa
    Member

  • Jessa_the_Professa
    replied
    I’m not following your photo.
    With Yangtze off the board, what is the diode mode reading on
    (1) VDD_MAIN ?
    (2) VDD_MAIN_YANGTZE?

    feel free to upload high resolution photos of your board from under a microscope for help finding where the water went

    Leave a comment:

  • penhitech
    Friendly Contributor

  • penhitech
    replied
    Hello again and sorry for not getting back to you faster,
    I have uploaded an attachment for VDD_MAIN_YANGTZE, As you can see my readings are completely off, so it is full short on the line..
    I also have confirmation that vdd main is shorted even with U3300 IC Off, My multimeter would read 0.00 Short in any vdd main component.
    I am not sure what do you mean with "Crisp Visual Exam", I am assuming you mean inspect it carefully and thoroughly?
    When I look at the board I can see some components that look kinda "Unshiny" on 1 side or sometimes both sides compared to others if that is my clue to find where the water went?
    Thanks Again!
    Attached Files

    Leave a comment:

  • Jessa_the_Professa
    Member

  • Jessa_the_Professa
    replied
    Water damage can not hide. Look at the board. Where did the water go? You can always see with crisp visual exam. It is possible that the water never hit the board. But if so, let us know. Crisp. Visual. Exam. What do you see?

    Leave a comment:

  • Jessa_the_Professa
    Member

  • Jessa_the_Professa
    replied
    Yes, remove the replaced Yangtze then use multi
    eter to see if vddmain is short

    Leave a comment:

  • penhitech
    Friendly Contributor

  • penhitech
    replied
    Hi, World Queen iPhone repair! and thank you for your answer,
    Actually, VDD_main is shorted to ground, my multimeter in diode mode is reading 0.00, VDD_MAIN_YANGTZE is also measuring the exact same thing, so both lines are shorted to ground.
    PP3V0_Nand for some reason is not short anymore! and it is reading 0.447 in diode mode, not sure how that happened tho!
    Actually, I was an idiot not to remember when the water went first, I always do, I mean it was submerged in water cause the customer dropped it while he was kayaking, but I cannot possibly pinpoint its exact location now...
    I know through schematics and ZXW that both vdd main and yangtze are related as you can see in my attachment, but I am not sure what to track and what to inspect, and now when I prompt the board to boot using DCPS, I Get 0.00a.. How is that possible when my multimeter confirms that I have a short on VDD_main? or is it VDD_MAIN_YANGTZE that is causing vdd main to short? Should I try Removing U3300 And see what happens?
    Thank you.
    Attached Files

    Leave a comment:

  • Jessa_the_Professa
    Member

  • Jessa_the_Professa
    replied
    The only tool that tells us whether or not you have a short on vdd_main or any other line is the multimeter.
    DC power and heat are only clues that tell us WHERE to use the multimeter to ask if a line is short.

    Is vdd_main short or not? What does your multimeter say in diode mode?
    Is PP3v0_NAND short or not? What does multimeter say?

    When a phone is water damaged, the problem is where the water went. Where did the water go on this board?

    Leave a comment:

  • penhitech
    Friendly Contributor

  • penhitech
    started a topic iPhone Xr 0.03a No Power

    iPhone Xr 0.03a No Power

    Hi,
    This is my very first post in this forum, I believe that is the best place to get solid answers in the whole free world.
    One of my customers brought an iPhone Xr water damaged, after putting the board in an ultrasonic cleaner for 10 min at 50w, I plugged it to DCPS (3.85V 2A), prompt it to boot with ny tweezers and then it would go up to 0.18A and then drop to 0 Amps.
    After injecting the same current and voltage into Vcc Main, I had PP_VDD_MAIN_YANGTZE line that would get extremely hot (325F) at the bottom left corner of U3300 IC and of course VDD_main itself was shorted because There is r3303 that is linking both lines.
    I then changed U3300 from a donor board, and then the circuit would not get hot itself and I would have 0.00A when plugged to a DCPS.
    Now I currently have a short on VDD_main, VDD_MAIN_YANGTZE and Also PP3V0_NAND, but the board would stay at 0 Amps and would not get hot at all anywhere when plugged in DCPS.
    I tried injecting 3.0v onto one the caps in PP3V0_NAND, with 1A and increased it gradually until it reached 2 Amps, I get a short on the DCPS, but nothing gets hot for me to track..
    I looked for a discoloration on any of PP3V0_NAND caps, even removed 2 or 3 of them that I suspected, but i got nothing.
    PP_Batt rail is reading correct values with ZXW, I am not sure how to address the issue anymore, or was injecting power into VDD_main a wrong idea after all?
    Thank you.

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