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iPhone 6 short on caps c1209 & c1202. could be short on cpu?

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  • iPhone 6 short on caps c1209 & c1202. could be short on cpu?

    1.)iphone 6 with no image/no power
    2.) I first run tristar tester with ambigous test result
    3.) I tested new ch port , then tristar testere showed dock test FAIL, so i continue to swap tristar, tristar test PASS with blue tristar tester, then still no image no boot, connect to itunes and not recognizing phone,
    so I removed shield after percieveing a burned smell, found C1505 cap shorted, D1501 Diode burned, I replaced diode then c1505 cap, short removed from there but also found a short in this other two caps c1209 and c1202 , notice that this caps point to cpu after passing thru a coil,
    4.) did noticed prior attemnpts
    5.) I'm guessing if short is caused by cpu, this is a non repairable phone?

  • #2
    Let's start from the beginning.
    First:
    History: How did the phone come to be like this?
    Visual exam: Is there water? Bend? Any prior repair attempt?
    We can't offer any advice on a phone until we know the whole story---every detail changes how we think about the phone.

    Next:
    What does the phone do on DC power supply? Does it show a short prior to boot, does it show a short after? Does it try to boot but just loops? Does it seem like it is booting normally but with no image? Does it just hang at 70mA? The pattern is our guide.

    You have skipped all of those essential steps and jumped into the middle. Go back. Start from the beginning.

    -----

    Now separately, I will give you some advice regarding what you have told us.

    1--Tristar Tester. The tester says "ambiguous results" if it detects only one line failed. I usually change tristar when I see this.
    The tester says DOCK FAIL when you have connected tester to the dock in the wrong direction, flip it around and test again.
    It sounds like you have changed tristar which and it passes tristar tester, so that should all be fine now.

    2--You found that you had C1505 short to ground. This CAN BE, but NOT ALWAYS IS a reason why an iPhone 6 can not boot. C1505 is on LCM_BL_ANODE which is fed from vccmain. IF the diode can still act like a wire THEN when you apply battery voltage, it will just go to ground through C1505 and your vccmain voltage will be zero and the phone won't boot. IF the diode is completely burned and is open line, then vccmain will be okay and not have a path to ground through C1505. In this case, the phone would boot and you would only have missing backlight. It is IMPORTANT to let your MULTIMETER be the guide, not just guessing. We can't know if the LCM_BL_ANODE short was the ONLY problem or not because we didn't measure what we should have here.

    3--Never REPLACE a cap, UNTIL you first TEST. Replacing means you are adding heat---replacing C1505 MAY have caused bridges under backlight driver, and now that's why the phone won't boot. We can't know. You should have tried to boot the phone with C1505 OFF before replacing.

    4--What makes you think the line that C1209 is on, PP0V95_FIXED_SOC, is short? Does it have zero volts when you attempt to power on the phone? Does it have a different diode mode reading than a normal iPhone 6? If the answer is "because it beeps to ground" THEN IT IS NOT SHORT. Stop using continuity method for short detection, that will lead you down the wrong path like here---all CPU power lines will ALWAYS BEEP TO GROUND IT IS NORMAL.

    5--Is this phone repairable? We have no reason to think that it is not---start at the beginning and we will find out.

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