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High current draw on sleep [Board repair]

Hi there!

So I got an iPhone 6 that came in for BaseBand CPU reball (classic searching no service issue) and battery replacement since it had poor battery life. While I was troubleshooting and ruling out any bad antenna/housing problems I noticed that after the phone is booted and it goes to sleep (locked screen, or stand by, whatever you want to call it) my bench PS showed normal current (low, like 40mA) for two seconds and then went up to 200mA and stayed there. This is very noticeable with the battery since it depletes a full charge in about an hour or so of being asleep.

I decided to do the BB CPU reball with short jumpers hoping that some cracked ball or the phone trying really hard to get signal would solve the issue but it didn't.

Things I've tried:

-Restoring with itunes (clean, no backup)

-New battery (of course)

-Known good battery

No signs of heat or physical damage on the board.

Board looked pristine before I worked on it, and since I see it going down to normal current values I ruled out any full shorts (maybe a parcial short, or full short on some circuit that only activates while the phone goes to sleep)

I have not asked about fake charging cables, but I have not seen this sympthom being Tristar related before, but maybe I'll replace it just to rule it out.

I've never seen this before.

Any ideas will be highly appreciated!

Regards from Argentina, Rodrigo.

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I agree... it is unique. But since Tristar acts as the voltage regulator (in a since)...I think you'd be on the right track there. Did you get your "Searching" issue repaired with u1 and v1 jumpers? or did housing and port make a difference??

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I agree, faulty Tristars can cause power draw issues. I had one case where it would draw power even when turned off when tested with DC bench power supply.

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Michael tristar technically works, I did a clean restore with no hiccups. As for the housing swap it kinda sorta worked but was too erratic, better results if I pressed on BBCPU while booting, so U1 V1 jumpers came in. I did the short jumpers though, if it ever fails and comes back to me I'll do the long ones.

Ben I've seen a few tristar with internal shorts on the PP_TRISTAR_PIN line (C1704) and they gave me a full short on bench PS while the phone was off. This is not the case though. Tristar seems fine if anything.

As for now, I replaced the battery with a new one and it seems to be working better now. Guess my known good battery is turning into known bad

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hello,

i have the same problem.draws 0.2A even in the sleep mode and pmic gets warmer gradually. i’ve re-placed tristar 3 times and same problem.even tried new battery.any suggestions?

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Rodrigo Maero será eternamente grato(a).
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