Hello and welcome to one more lesson
we have to polish and understand very well phones that doesn't turn on
remember that there's the course of I2C, you should have seen that course
if you haven't seen it then you have to because the I2C also has a lot to do with the phone not turning on
then I decided to separate it, because
here I'm talking a lot about PMIC, CPU, NAND, BUCK, LDO
but is very important that you see the I2C course if you haven't
you can see so you can understand many other things as well that can cause the phone not to turn on
in this class we called it "how to interpret these consumptions".
I think that many people
they get complicated, to say it in some way
when a phone doesn't turn on, when you only need to know how the phone works
so we can know where we'll diagnose and to know when we need to rest
like that I don't repair some phones, there will be some times where you'll get some phones
you may have a conclusion and say "if the PMIC is working
if NAND is working, if I2C is working
then it has to be the CPU, maybe because of a bump, a short or a bad soldering
if you have practice you can remove it, but the point is
if we know how the phone works, we'll be able to diagnose faster
solve problems faster
and rest faster
"I have measured everything, everything is working, so the CPU is the one that doesn't respond
it is resting and doesn't want to do anything
this is regarding consumption, I want to take my time on this but I think I will do it in 2 parts, because
you'll get many phones with consumptions, so I want to explain how
we can apply everything we have learned in practice
let's start again, we'll do the same drawing
here I have a supplier, a battery, with positive and negative
this battery generated a line called V_BATT
then it reached a Tigris
and a Mosfet, here I'm not talking about
initial consumptions because we already saw it in previous lessons
just by connecting the power supply and if it soared, we know that we can have a consumption
in a Main line or Secondary line
let's summarize the Main line
Tigris, Mosfet, this line V_BATT
we can draw the line that goes here, and it connects to IC 1, here is IC 2
here is IC 3, and here is IC 4, 5 I don't know how many of them are
this is being powered by the battery line
but the Mosfet internally generated a line called VCC_MAIN
this line VCC_MAIN
will go and... let's do the same drawing
it will power the IC1, IC2, IC3, IC4
and here let's put like 30 more components
now I'll change the color to separate the lines
this line also has many capacitors, these are parallel capacitors
this whole line
what I'm doing here and what am I going to put on the computer
Let's go to the computer, and I'll show you, what I just did is, first we're going to start with the battery
what I just did was touch this, and what I drew was, for example, I indicated that I touched here
this component, this component
this circuit, and it is also touching another circuit and another circuit but I'm also indicating
that there are capacitors
what I'm doing here is, is an interpretation of that but in a graphic way so that we understand it
the same with VCC_MAIN, I'll draw a line from here
and what I'm going to do is connect many capacitors here
ok, these are parallel capacitors
parallel capacitors, so here I have
2 main lines
main lines
by just connecting the battery, this will send a voltage between 3.8 volts to 4.1 volts
and more or less 5 amps, which is what I put in with my power supply
ok just by connecting it, so
when I connect the battery
the electrons, current and everything will flow here
will arrive here and generate the battery line
here reaches the Tigris
but this line also reaches the Mosfet and the line goes here
it will power each of these circuits
on it's way it will also power these capacitors
the first line of the battery is already powered
now we said
internally from the Tigris and the Mosfet, these lines will link together
the current with their voltage will pass, and now they turn into VCC_MAIN
now it goes here and will power circuit 1, 2, 3, 4
about 30 more components
and will also power the capacitors
remember, the energy in the capacitor only gets here, they store energy
they store energy in case of voltage drop
this right here is Ground
this here too
and the same with the battery line
capacitors store electrons on their positive side
and the circuits are ready to go if someone orders a command to make them work, they are already powered
in theory, these are the Main lines
if we go again to the ZXW
this is the battery line
but internally in Tigris
Mosfet and Tigris join together
those I have just marked, this and this
are these that I drew here
the battery line links with VCC_MAIN
internally in Tigris and Mosfet, and are these two components here
the line is now called VCC_MAIN, and look how many of them it powers
all of those components and circuits
and it also powers these components, they are many
so that's it, I'm trying to do my best, please pay attention so you don't miss out
ok, these
are the first 2 Main Lines, just by connecting the battery, all this I drew occurred
so now my power supply can show
let's mark this with other color
my power supply will show, without turning on the phone, 4.1 volts
and 0.000 amps, because there's nothing, everything is fine
this is before turning it on, I haven't turned it on yet
here
well, later I'll draw the PMIC
now
what happens if my power supply, by connecting the battery, this says 4.1 volts and 5 amps?
a sudden consumption with all the amperage
what happened here?
let's mark with blue, the blue is the color I'm using to represent the current and voltage
the power supply soared to 5 amps
what's happening here?
it turns out that because here I have 5 amps that I'm injecting with my power supply
someone in this little squares is consuming everything
imagine it could be this one
this one said "Edgar, today I don't want to work, I'll attach" and is attaching to Ground
so what happened?
the 5 amps I had here went directly like this
they went over here and now "let's heat here"
Which line is short? V_BATT, the line of the battery
now
What if the power supply shows 5 amps but it was due to one of these
this one said "Today I don't want to work, I'll attach to Ground"
one more time the 5 amps that I'm injecting it
with the power supply goes like this
it goes through Tigris, and here it will go through these "not here, not here, not here, let's go on"
and it will go through Tigris, Tigris has a line called OVP
which means Over Voltage Protection
so this Tigris is off, but the Mosfet is in series
here the 5 amps will pass through
causing the Mosfet, in this case if we go to the microscope
this will heat up
why? Because the whole current is passing by
but it is passing because there's someone in short who's saying "I'm in short"
this is shorted, but because everything is passing here
this will heat up, we already know to remove it, how to search it, how to attach that with a wire
so that the current does not dissipate here, do not heat the Mosfet and reach the capacitor
We're good? This would be a full consumption with the power supply
"Now, Edgar, what happens if it goes to 5 amps?"
We have already seen how to know if it is because of battery or VCC_MAIN
we have already seen that we can measure them
we can measure them
"But what happens Edgar, if I measure and I have nothing to Ground? I don't have a short?"
you don't have a leak but still
y power supply shows, for example, it doesn't show 5 amps
but now it shows 0.150 apms
Ok, what happens if it shows this?
I put the multimeter in this line, it didn't beep, I don't have leak
then I put my multimeter here, as we learned, I don't have leak or Ground
what's going on?
It could be a circuit
Let's imagine this circuit, the number 2 is wet, internally is full of tartar
it is causing a consumption
A Main consumption, why? because it is being powered from here
is being powered and it is consuming, just a little but it is consuming
it will be consuming 150mA, you can see in your power supply a consumption
there will be no short or leak in VCC_MAIN or V_BATT, but you'll see a consumption in the power supply
the same can happen, imagine if it was not on the battery line
but it was the number 4 here, because it was poorly soldered
and these lines are attaching, what's going to happen?
you'll have your consumption in the power supply of 150mA
there will be no short circuit or leakage on any of these lines, but you will have a main consumption
there's no short because when you're looking for them, you're looking for a short to Ground
but because these are fine, these said "Today we're good, we'll work"
no one is going to Ground
what does this mean?
this means that someone else is causing this consumption
so this means the power supply has 5 amps, is powering everyone here
but it passed through Tigris and Mosfet, powered these but here someone is saying "Help"
and it is consuming 150mA without turning on the phone
so I'll have an initial consumption because this one is consuming
"Edgar, and how I'm going to find these consumptions?"
With Rosin, freezing the board, with thermal camera, you have to find it
if you have a consumption by only connecting it to the power supply, then you have a Main consumption
either in a parallel capacitor or in a circuit as we saw earlier
This explanation is very important for you to understand because
for now you don't need to memorize and say "ah yes, it's 150mA, what can it be?"
"if they are 20mA, what can it be?"
yes, there are very low consumptions
that are hard to find, but you have to
can look for line leaks, shorts, or circuits that get hot
so this and the next lessons are very importants
they are very important because
you have to understand how does this works, how this drawing shows how everything gets powered
if you have an initial consumption, then that means the problem is a circuit
that's being powered by just connecting the battery
by just connecting the power supply and you have a consumption, it must be a circuit or a component
that's being powered by a Main line
because those lines are generated by just connecting the battery
please review this lesson carefully
tell me in the comments if you did understand
For now I do not care what consumption you have, but if it is an initial consumption we have to look for it in the main lines
battery, VCC_MAIN, components that are powered by those, and we can discard them with what we have learned
so let's mark this lesson as completed and move to the next one