No volts to PP3v3_ACC Line to Tristar. No amps

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iPhone 6

这款4.7英寸iPhone于2014年9月19日发布，是iPhone 6 Plus的缩小版。

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Stephen Elliott @mdrecovery

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发帖于: 2017年1月11日

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No volts to PP3v3_ACC Line to Tristar. No amps

So I'm in the process of a data recovery and am stuck in a spot. Short story customer dropped iPhone, now phone acts as if in dfu mode. No image on screen and no amps coming through when plugged in.

Computer recognizes in recovery and when plugged in using ammeter no amps are coming through. Already swapped shorted capacitor on pp3v3_acc line and currently getting no volts through that particular line.

I know you need all three rails incoming to provide voltage for this chip to work. PP3v0_tristar and pp1v8_sdram show correct voltage. PP_vcc_main is good as well as PP_batt_vcc.

Rail pp1v8 is shorted and haven't looked at that yet but figure I might as well start with tristar.

To my understanding pmu u1202 provides power through cap c1299 to u1700 tristar.

Is it possible for u1202 pmic to be the culprit even if other rails coming out of it are reading correctly?

Biggest questions is why is this rail getting 0 volts.

Any help would be greatly appreciated, thanks in advance!

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Minho @refectio

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Don't worry about the PP3V3_ACC line. It is only active for a very brief period of time when the phone is powered on. It is used to power devices connected in the Lightning Port.

Check PP_BATT_VACC, PP_VCC_MAIN and PP5V0_USB (when a charger is connected). Those are your main power rails. Then check the main rails coming out of the PMIC (like PP_CPU, PP_GPU, PP1V8 etc...). If you find a short, then focus on that first. Follow the schematics to identify all of the caps in the line. Inspect visually and if necessary, remove them one by one.

Don't just replace U2 for the fun of it...unless you're really good and it actually is fun :>).

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may I ask where you guys get the schematics for these iphones ?

由 Shrubbery 完成的 2017年1月11日

@shrubbery the interwebs :)

由 Gigabit87898 完成的 2017年1月11日

I swapped damaged transistor as well as tristar for funs lol. Found transistor to ripped in half and figure tristar takes 10 minutes. Also found short in pp1v8 so now I get to go through the capacitor rabbit hole. Problem is no liquid damage only drop damage so no visible damage to caps.

由 Stephen Elliott 完成的 2017年1月11日

Also minho thanks bud I really appreciate it.

由 Stephen Elliott 完成的 2017年1月11日

@gigabit87898 I'm old, what are the interwebs?

由 mayer 完成的 2017年1月11日

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may I ask where you guys get the schematics for these iphones ? — Shrubbery
I swapped damaged transistor as well as tristar for funs lol. Found transistor to ripped in half and figure tristar takes 10 minutes. Also found short in pp1v8 so now I get to go through the capacitor rabbit hole. Problem is no liquid damage only drop damage so no visible damage to caps. — Stephen Elliott

iPhone 6

No volts to PP3v3_ACC Line to Tristar. No amps

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