water damaged iPhone 6.

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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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Mobilefi @inspiraattori

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发帖于: 2017年5月12日

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water damaged iPhone 6.

Hello @refectio! I have water damaged iPhone 6. It is cleaned and there are missing C0633. There was also vvc_main short in ground in board so I take one cap that was caused the short (C3220_RF) and now the short is released. I also take off two caps that was short to ground (C1695 and C1433) but they are not in vvc_main. I blugged it without all those caps to charger and tested it with multimeter and it gives me 3.5v and booted up to lockscreen. Then I blugged it in charger and it turned off. then I tested the charging line and now it give only 1.5v and not turning on anymore.. Do you think that it was mistake to blug it in charger without all those caps? And what to do now.. putting all those caps on and probably new tristar maybe?

Short to ground line

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Minho @refectio

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I don't believe the absence of those caps would impede the phone from booting. It might make things behave oddly in certain circumstances though.

For example, C1433 is a decoupling capacitor and it is located as close as possible to U1400. When powered, it stores an electrical charge that can be used to supply current on a moments notice whenever the IC needs it. Normally the power supply would do this but due to parasitic inductance, it can’t respond quickly enough. Having the decoupling capacitor right next to the IC, it can supply the peak current required. The other effect is that it filters the line from noise called ringing (caused by high frequency switching), which can have crippling effects all over the circuit board. The same is true for C1695 & C0633.

So yes, they should be replaced but the phone should work without them for testing purposes (therefore you did not make a mistake). Before replacing Tristar, you could probe your main lines as well as the output lines from the PMIC (U1202).

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Thank you for the answer @refectio I've now replaced all those caps but still no booting and in battery connector I tested input voltage (plugged in charger) and it's still about 1.51v. Sorry my bad English but what you mean with this last sentence: "you could probe your main lines as well as the output lines from the PMIC (U1202)."?

由 Mobilefi 完成的 2017年5月14日

You will want to check you main voltage rails to see if they are shorted. Start with VCC_MAIN and then look at the main output lines coming from the PMIC/PMU (U1202). For example, check PP_CPU & PP_GPU (these two are low resistance), PP1V8_SDRAM etc.

由 Minho 完成的 2017年5月14日

Thank you very much for helping me! I found shorted line in PP_CPU. This shorted line include 12 caps and two coils. Please take a look the latest picture in my question. Do I have to pull all of them and replacing one by one or what you suggest to do next?

由 Mobilefi 完成的 2017年5月19日

What resistance are you measuring on those lines? They are low resistance lines, typically in the 30-80 Ohm range. They will "beep" on some meters in continuity mode so you have to look at the actual value. If you are seeing between 0 and 1 Ohm while the phone is completely disconnected, then you may have a short.

Regardless of which rail is shorted, I usually remove one cap at a time and test both the cap and the rail, then repeat

What you need to determine is if a short is coming from the PMIC or downstream (caps, CPU etc.). One way to do that is to remove the coils (L1209-1212) and then test each side. It will either be on the PMIC side, in which case that's what you replace or its downstream which could mean caps or CPU.

Again, look at the measurement first so you don't work for nothing.

由 Minho 完成的 2017年5月19日

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Thank you for the answer @refectio I've now replaced all those caps but still no booting and in battery connector I tested input voltage (plugged in charger) and it's still about 1.51v. Sorry my bad English but what you mean with this last sentence: "you could probe your main lines as well as the output lines from the PMIC (U1202)."? — Mobilefi
You will want to check you main voltage rails to see if they are shorted. Start with VCC_MAIN and then look at the main output lines coming from the PMIC/PMU (U1202). For example, check PP_CPU & PP_GPU (these two are low resistance), PP1V8_SDRAM etc. — Minho
Thank you very much for helping me! I found shorted line in PP_CPU. This shorted line include 12 caps and two coils. Please take a look the latest picture in my question. Do I have to pull all of them and replacing one by one or what you suggest to do next? — Mobilefi
What resistance are you measuring on those lines? They are low resistance lines, typically in the 30-80 Ohm range. They will "beep" on some meters in continuity mode so you have to look at the actual value. If you are seeing between 0 and 1 Ohm while the phone is completely disconnected, then you may have a short.

Regardless of which rail is shorted, I usually remove one cap at a time and test both the cap and the rail, then repeat

What you need to determine is if a short is coming from the PMIC or downstream (caps, CPU etc.). One way to do that is to remove the coils (L1209-1212) and then test each side. It will either be on the PMIC side, in which case that's what you replace or its downstream which could mean caps or CPU.

Again, look at the measurement first so you don't work for nothing. — Minho

iPhone 6

water damaged iPhone 6.

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