how to read schematics

[Arkanggel10]

hello,i have seen macbook schematics where they have a page with power rails, this makes life much easyer when it comes to look for the present voltages to identify problems.

but i came across with some other manufacturer boards schematics that dont have this page. in this situations how we know the correct voltage to seek in "test points"

i have iphone 4s schematic as well and it has a page named "test points" it show location and description, but not the correct value that they have to show in order to the device works.

how we process in this situation?

i started to seek information about the subjet, but its very hard to find... its like magic tricks, magicians dont want us to know tricks.

in this subject its the same, tecnicians dont want other people to know "tricks"

thanks

[budm]

Re: how to read schematics

If you can look up the spec sheet of the IC then you will have the ideas of what the Voltage should be, it is better than nothing.

[SteveNielsen]

Re: how to read schematics

in this subject its the same, tecnicians dont want other people to know "tricks"

thanks

It's the manufacturers who don't want us technicians knowing their tricks.

[Arkanggel10]

Re: how to read schematics

the manufacturers dont want you to have the schematics in the first place, yet i see them around...

i can only think that this is kind easy to learn and manage, otherwise people would talk about it.

i will make paypal donation to who can help me, and if someone dont want to talk public in topic plz pm me

[budm]

Re: how to read schematics

"Originally Posted by Arkanggel10 View Post
in this subject its the same, tecnicians dont want other people to know "tricks"

thanks"

We all share our tricks and knowledge here at BadCap.

[budm]

Re: how to read schematics

Instead of PM me, how about posting the circuits that you are trying to learn so every one here can give you the answers, there are many great people here with large amount of experience.

[Arkanggel10]

Re: how to read schematics

i already asked some questions in my first post.

can i attach schematics in here? no risk of getting banned or something?

first, like i said i've seen macbook laptops schematics where you have power rails, they show you what rails create others, it helps you a lot to follow them and check them...

in other manufacturers schematics and iphones schematics that i've been trying to understand you dont have pages like the ones in macbook's. in this case how we know the voltages in the rails?

[budm]

Re: how to read schematics

We upload the schematics and service manuals here all the time, no problems.

[Arkanggel10]

Re: how to read schematics

ok you have it here

[budm]

Re: how to read schematics

See those power pins with labels?
For example:
PP1V1 = 1.10V power supply
PP1V2 = 1.20V power supply
PP1v8 = 1.80V power supply
PP3V0 = 3.00V power supply

Get the ideas now?
All you have to do now when you see something like that is to make the measurement to verify.

[budm]

Re: how to read schematics

Your PM: "hi there, you can read schematics with no problems?

can you help me with my doubts?

i can make you some paypal donation if you do"

See these and tell me if you still have doubt:
https://www.badcaps.net/forum/showth...581#post564581
https://www.badcaps.net/forum/showth...inum+SW-10+v.2

Lots of people here can read and capture Schematic and also make PCB layout.

[Arkanggel10]

Re: how to read schematics

in page 14, we see PP_BATT_VCC and PP_VCC_MAIN on Q4 component.

this are voltage lines, but how do we know their value?

the pp_batt_vcc, i am assuming that is the voltage of the batery but the other one?

i tryed to look in internet for the datasheet of q4 (CSD68803W15) component, but without sucess...

in same page in angelina chip we see some voltage lilnes with pwr2500 or pwr2000, is that important? what does that mean?

thank you very much for your tips

[popeye]

Re: how to read schematics

Have a look here look for basic electronics.https://www.youtube.com/user/rossmanngroup/videos

[SteveNielsen]

Re: how to read schematics

the manufacturers dont want you to have the schematics in the first place, yet i see them around...

i can only think that this is kind easy to learn and manage, otherwise people would talk about it.

i will make paypal donation to who can help me, and if someone dont want to talk public in topic plz pm me

Some schematics get released, not all, and some of those are free, some cost money. There are a great many that are not available online or otherwise.

Perhaps I misunderstand you but it is not easy to learn. It takes time because there is so much to it and you never stop learning. Electronics is a science.

There is no reason anyone here would not freely share information they have. It's best to keep the tech discussions public for the benefit of others to learn and add to.

[budm]

Re: how to read schematics

As you can see, Q4 is a P-CH power MOSFET, when the phone is not being charged and in running mode, the PP_BATT is fed through the body diode of the MOSFET so the output will be = PP_BATT - Vf of the body diode, so basically the PP_VCC will be very slightly less than the PP_BATT. When in batteries charging mode Q4 is then turned on by U5 (looks to power management control IC).
I thought you know how to read the diagram and understand how the component functions. If not you should read up on how devices function, it take basic knowledge of the component function to at least get the basic understanding how the circuit functions.
pwr2000 (is not the netlist, just the name) is 1.2V for PP1V2_SOC.
pwr2000 (is not the netlist, just the name) is 1.2V for PP1V2_CPU.
They are two outputs of the 5 buck regulators (BUCK0~BUCK4) switching power supplies of U5.

[Arkanggel10]

Re: how to read schematics

thanks a lot for the help, i will study this more, and if i find something that i dont understand, i post again.

[Arkanggel10]

Re: how to read schematics

budm, i have here one iphone 4s that the front camara its not working, can you help me figure out if i need to buy another camera or if is some component that is damaged?

[budm]

Re: how to read schematics

See page 19 for the cameras connectors to see you have power to power the camera (you will probably has to activate the camera function), you will need oscilloscope to see Video signal if it uses analog Video signal.
Does this phone have two cameras?

[Arkanggel10]

Re: how to read schematics

yes, it has 2 cameras, cant do any testing with multimeter only? like testing if voltage coming to the camera or something?

i dont have oscilloscope yet...

[budm]

Re: how to read schematics

Duplicated posting, please ignore.