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Hi this iphone 11 suddenly switched off and it didn't turned on so to check I connected motherboard wilth new battery, screen, charging flex etc but didn't turned on.
So I connected to power supply but still no improvement, it even did not draw any current.
After separation of board I checked, following are the short I have found.
FB_BU_CK12
PP_SRAM_S1
PP_CPU_PCORE
Pp_GPU
Can anyone please help.
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Репутация: 5,4к
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hello Sharanabasappa G,
on what basis do you find a short circuit on these lines? what is the indication of the multimeter? Are you aware of the presence of logic lines, impedance, resistivity, impulse response and many other phenomena in microelectronics today?
Go back to basics, read a lot, and learn quickly.Turn off YT, you won't find anything of value there at this point.
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Hi, following are the diode and resistance value
PP_CPU_PCORE-0.046v--23ohm
Pp_GPU-0.016v-8.6ohm
Are the short?
U have mentioned that if no current draw even after trying to boot then no short, but if there is no short y it is not turning on?
:) yes, if there is no current after prompt to boot, there is no short circuit there. A short circuit is a physical phenomenon that is governed by laws. If you do not have line current after atempt to boot, it can only mean that the Volts do not reach the point of measurement or are not directed that point. You have to return the current distribution path to the source. Somewhere you find a jam or the main generator is not working. There is no other possibility in the known universe. In the event of a short circuit, you would see it as current flow above the extremes. The technical short circuit starts at <5-6 ohms. Everything else is low-resistance lines of processor synapses to induction lines.
@tojaert Thank you so much, sorry for asking silly question since I'm 1st year engineer, I am trying to figure out the problem so that I can save some money.
Can you please tell now what should do? Do I need to check voltage across lines?
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to answer your question:
you need some equipment (you don't write anything about it, that's important). Multimert with diode function, laboratory power supply (3 digits after the intersection) and some time to trace the diagrams. Try to get some, there is quite a lot of it in the net.
Separation heater - the soldering iron is an absolutely essential tool. You need to separate the sandwich and find out why you don't have electricity in the installation. You need to establish the primary supply voltage (3.8V), second order (3.0V, 2.8V) and third order (1.8V). These power the devices necessary to run, without which the motherboard will hang in nothingness. The BGA soldering skill may come in handy here, you should practice somewhere before.
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And I have separated the iphone board and I have all the material u said,
Репутация: 127
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Those lines arent shot, theyre low resistance lines so most multimeters will beep or indicate a short. You can send in your phone for repairs if youre not so experienced and dont have the tools. You are from?
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Hi thx for the reply, I have tools and I thought to repair it by myself. And I'm from India
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If there is no current draw on or before prompt to boot you do not have a short on the logic board. I would take @tojaert advice.
из Chris Stables