Iphone 4s logic board - what are these? - GSM-Forum

geekgirl123 · 03-03-2015, 13:58

I am learning.
I have the logic board out for 4s and I am learning experimenting with my multimeter. (my iPhone is not charging even though it says it is - I replaced batteries, and dock connector - so I assume logic board)

But anyway, i want to learn. I did a continuity test on these little connectors and it worked for the black things, but not the reddish things. Why only the black, what are they called.
how to troubleshoot using continuity test for battery not charging
(i sorry i can't upload pic), but there are black diodes, reddish, blue etc)

gkhn · 03-03-2015, 17:44

there are several type of components are placed or used on a logic board. Its a lot actually.

You can google them

- Resistor
- Capacitor
- Diode
- inductor
- Fuse
- Opamp
- Voltage regulator
- FPGA
and so on.

I done quick search on your problem and you can find a few solutions on google. Search for iphone 4s fake charging solution and you can see a pic with a red wires goes from C92 to C225.

Otherwise search for iphone 4s fake charging here and google.

geekgirl123 · 03-05-2015, 11:16

Thank you, I see solution and found these on the logic board.
How to jump, connect wire from c92 to c225? solder it on the capacitors?
or remove c92 and c225 first.

Thanks for help

gkhn · 03-08-2015, 22:23

you need to solder a wire from c92 to c225. its should be a thin wire. But you need to be very carefull, because if your wire touches the other components and touches the shield or other parts you can damage your phone. Use a insulated wire so you do not short anything.

JoeBean · 03-11-2015, 17:48

Get a cheap wrist watch and tear it open to get fine wire that will work for jumpers. You need a good magnifying glass or, ideally, a microscope to see what you are soldering. And a very fine soldering iron tip. Just play with it. Since it isn't working there's not much you can do to make it worse and you might learn a great deal. Look for a used microscope that has a lot of distance between the work and the optics to let you get a soldering iron in there. I do most work at 4.5x, and inspect the board at 45-90x.

If you get a microscope you can use it to search all those small parts on the board. Often some will be missing or damaged and that will be where your problem is. Then go to the sticky links on this board and get the schematics, find what that component is called (eg. c286, fl8, etc) and Google that. You'll see what it's used for, and then when you look at the schematic you'll get a better idea of how the picture relates to real life.

For what it's worth, the 4 and 4s are two of the most troublesome board Apple ever put out. I hate them, but I've made lots of money fixing them

03-03-2015, 13:58	#1 (permalink)
geekgirl123 Junior Member Join Date: Apr 2013 Posts: 15 Member: 1928023 Status: Offline Thanks Meter: 1	Iphone 4s logic board - what are these? I am learning. I have the logic board out for 4s and I am learning experimenting with my multimeter. (my iPhone is not charging even though it says it is - I replaced batteries, and dock connector - so I assume logic board) But anyway, i want to learn. I did a continuity test on these little connectors and it worked for the black things, but not the reddish things. Why only the black, what are they called. how to troubleshoot using continuity test for battery not charging (i sorry i can't upload pic), but there are black diodes, reddish, blue etc)

03-03-2015, 17:44	#2 (permalink)
gkhn Major Poster Join Date: Jan 2010 Location: Europe Posts: 42 Member: 1208225 Status: Offline Thanks Meter: 13	there are several type of components are placed or used on a logic board. Its a lot actually. You can google them - Resistor - Capacitor - Diode - inductor - Fuse - Opamp - Voltage regulator - FPGA and so on. I done quick search on your problem and you can find a few solutions on google. Search for iphone 4s fake charging solution and you can see a pic with a red wires goes from C92 to C225. Otherwise search for iphone 4s fake charging here and google.

03-05-2015, 11:16	#3 (permalink)
geekgirl123 Junior Member Join Date: Apr 2013 Posts: 15 Member: 1928023 Status: Offline Thanks Meter: 1	Thank you, I see solution and found these on the logic board. How to jump, connect wire from c92 to c225? solder it on the capacitors? or remove c92 and c225 first. Thanks for help

03-08-2015, 22:23	#4 (permalink)
gkhn Major Poster Join Date: Jan 2010 Location: Europe Posts: 42 Member: 1208225 Status: Offline Thanks Meter: 13	you need to solder a wire from c92 to c225. its should be a thin wire. But you need to be very carefull, because if your wire touches the other components and touches the shield or other parts you can damage your phone. Use a insulated wire so you do not short anything.

03-11-2015, 17:48	#5 (permalink)
JoeBean Junior Member Join Date: Jan 2015 Posts: 18 Member: 2334964 Status: Offline Thanks Meter: 8	Get a cheap wrist watch and tear it open to get fine wire that will work for jumpers. You need a good magnifying glass or, ideally, a microscope to see what you are soldering. And a very fine soldering iron tip. Just play with it. Since it isn't working there's not much you can do to make it worse and you might learn a great deal. Look for a used microscope that has a lot of distance between the work and the optics to let you get a soldering iron in there. I do most work at 4.5x, and inspect the board at 45-90x. If you get a microscope you can use it to search all those small parts on the board. Often some will be missing or damaged and that will be where your problem is. Then go to the sticky links on this board and get the schematics, find what that component is called (eg. c286, fl8, etc) and Google that. You'll see what it's used for, and then when you look at the schematic you'll get a better idea of how the picture relates to real life. For what it's worth, the 4 and 4s are two of the most troublesome board Apple ever put out. I hate them, but I've made lots of money fixing them