Tristar iPhone 7 DCPS 0.2 Amp

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iPhone 7

Rilasciato il 16 settembre 2016. Modello 1660, 1778. Disponibile come GSM o CDMA / 32, 128 o 256 GB / Rose gold, gold, silver, black e jet black.

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AGS @ags_studio

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Postato: 18 ott 2018

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Tristar iPhone 7 DCPS 0.2 Amp

HI Everybody, (specially @refectio )

I have a question only for general knowledge plz.

I have an iphone 7 for repair.

The story of phone is, client charging the phone in his car, and he see the smoke coming out from phone and iphone dead (i know i speak perfectly english language, thanks for compliment) :)))

I check battery , dock flex, every voltage Tristar , mosfet , 5v usb every nand voltage and every thing is perfect but telephone wont boot.

When i connect it to DCPS on amp screen show max 0.2 ahm fix, some time ahm move (from 6 to 22) but after some seconds, 0.20.

In the last i change tristar and phone turn ON and work perfectly.

So my question is :

When we have these situation , the Voltage check is useful or not??

I cant understand if Tristar voltage is ok (with schematic help) it doesn’t mean the chip work perfectly???

Ususally in this case i change tristar or mosfet or Tigris IC.

But this time i choose to be “professional” and check every voltage with tester, but in the last the problem is in Tristar.

So coulld u tell me plz if voltage check is helpful , and when u have any dead phone who absorb minimun amp but dont boot and screen not show nothing, which is the step you follow.

Thanks everybody

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Soluzione Prescelta

Minho @refectio

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Postato: 18 ott 2018

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There are a few different schools of thought in that regard. Some techs will replace components with little diagnostic other than to acknowledge the visible symptoms. On some problem types, that is sufficient. Other techs will probe more deeply.

IMHO, there is no perfect way of doing things, it depends on your personal style and experience. The more experience you gain, the more likely you are to determine the proper diagnostic quickly. In my answers, I encourage techs to probe deeper so that they understand what they are doing and avoid asking for “plz bro” solutions. When you feel you have seen enough Tristar failures to know when to just “replace the chip”, then you will intuitively know when to stop doing extended probing for those failure types.

However, some techs flip chips without really thinking the problem through. They will replace Tristar, Tigris, the MOSFET… and the PMIC for good measure when the problem may have been simpler (Lightning Port ;>) or just an incorrect re-soldering of the Tristar. Every time you flood the board with heat, you risk damaging it further so that’s why I encourage newer techs to probe.

As for the Tristar IC itself, it can be a tough one to troubleshoot. It rarely has a power rail short but fails often nonetheless. That’s because it is a communication IC and it can fail internally without showing typical external symptoms.

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Thank u very Much @refectio . you explanation are always helpful :)

So How can u know exactly , how the phone work??

Schematic non always is clear for persone like me who dont have a electronic background.

So i m interested to study in detail (for example iphone, because i repair only Apple Phone).

I ask this , because my aim is repair only dead device,

Now i repair board, (but change only change ic’s , backlight ecc ecc).

Cuold u plz explain me how the phone work , what happen exactly inside the phone, when we connect battery?

usually when i have dead phone i follow this step :

Connect to DCPS,

Check battery ,

Dock Flex,

And then mother board, starting with :

VCC BATT

Mosfet

Tigirs

Tristar

NAND Voltage

???

Ih this a good begning ??

Thanks a lot again for you time

19 ott 2018 da AGS

Like I said, everyone develops their style. You can never really know everything that is going on because Apple doesn't use of-the-shelf parts with publicly available datasheets. Sometimes the trick is to look up Apple patents for a deeper understanding or similar components to get a sense of what the chip does and doesn't do.

21 ott 2018 da Minho

If you are going to be doing board level repairs as a business, I think you should be investing some time and effort to understand at least the basics of electronics. Once you understand what a resistor, capacitor or inductor (coil, choke, ferrite bead) does and how they behave, you will know how to test them and whether or not it can be shorted or removed.

This is a good tutorial on how engineers deliver clean power to IC's. This is very relevant as the majority of the passives on an iDevice logic board are there for this specific reason. There are several articles in the series and they touch on capacitors and ferrite beads (filters). Another good source of materials is ElectronicTutorials. There are also some good youtube channels such as Afrotechmods, AddOhms and of course the EEVBlog.

21 ott 2018 da Minho

@refectio thanks a lot Minho Sir..

I already repair and read theory, read your comments and watch videos.. thanks a lot for help :)))

26 ott 2018 da AGS

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Thank u very Much @refectio . you explanation are always helpful :)

So How can u know exactly , how the phone work??

Schematic non always is clear for persone like me who dont have a electronic background.

So i m interested to study in detail (for example iphone, because i repair only Apple Phone).

I ask this , because my aim is repair only dead device,

Now i repair board, (but change only change ic’s , backlight ecc ecc).

Cuold u plz explain me how the phone work , what happen exactly inside the phone, when we connect battery?

usually when i have dead phone i follow this step :

Connect to DCPS,

Check battery ,

Dock Flex,

And then mother board, starting with :

VCC BATT

Mosfet

Tigirs

Tristar

NAND Voltage

???

Ih this a good begning ??

Thanks a lot again for you time — AGS
Like I said, everyone develops their style. You can never really know everything that is going on because Apple doesn't use of-the-shelf parts with publicly available datasheets. Sometimes the trick is to look up Apple patents for a deeper understanding or similar components to get a sense of what the chip does and doesn't do. — Minho
If you are going to be doing board level repairs as a business, I think you should be investing some time and effort to understand at least the basics of electronics. Once you understand what a resistor, capacitor or inductor (coil, choke, ferrite bead) does and how they behave, you will know how to test them and whether or not it can be shorted or removed.

This is a good tutorial on how engineers deliver clean power to IC's. This is very relevant as the majority of the passives on an iDevice logic board are there for this specific reason. There are several articles in the series and they touch on capacitors and ferrite beads (filters). Another good source of materials is ElectronicTutorials. There are also some good youtube channels such as Afrotechmods, AddOhms and of course the EEVBlog. — Minho
@refectio thanks a lot Minho Sir..

I already repair and read theory, read your comments and watch videos.. thanks a lot for help :))) — AGS

iPhone 7

Tristar iPhone 7 DCPS 0.2 Amp

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