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Modern Cell Phone Practical Jumper Setting

8 Jun 2018
jumper setting is typically best when you need to connect two different points on a cell phone there could be internal disturbances in the circuit of the handset which are connecting these two points and
because of the internal disturbance or a breakage in the circuit, the father or data may not be traveling
from one point to the other easily and in those cases, we use jumper setting to try and connect those two points directly thereby ensuring the correct transmission of power, data, and piles voltage from one end to the other end but in order to determine whether you need to do jumper setting.
for example, if you're checking a battery connector you may need to first verify whether the battery connector is working properly or not before you decide to make any changes or test any connections on the cell phones

Tracing & Testing VCC main and GND points of a iPhone PCB
removed all the suspect caps on vcc main but still shorted. wanted to try freeze method, but don't know where to put power
iphone 6 battery connector

now in this iPhone, the first aspect that we were going to be checking is the connectivity between the battery connector and two other important basic electronic components that transmit power to the rest of the circuit of the cell phone now in order to test out the connectivity in the phone PCB you need to use the multimeter!
what do multimeters measure? how to use multimeter to test continuity
best multimeter for home use

if you don't know how to use multimeter check read this article first what do multimeters measure? how to use multimeter to test continuity
place the multimeter switch range on the Buzzer continuity testing mode to check whether the two probes are connected things the means a
7 Function Digital Multimeter Leads Electrical Circuit Test Meter Detector Tool
multimeter probe types
and you can hear the beep and once you hear the beep the multimeter is perfectly alright let's go ahead and test the connectivity on the board now typically we are going to be starting off with checking the battery connector

Step 1 Check Shorting on Cell Phone Battery Connector

check shorting on cell phones with multimeter We can easily check whether there is shorting in the circuit board
positive negative bsi 
Battery Connector connects the battery positive and negative to the mobile PCB internal plus and minus copper wire prints. if you don't know how to check Shortage on cell phone circuit from the battery connector read this article how to fix a short circuit iPhone

Step 2 Checking Cell Phone PCB Ground Resistance with a Multimeter

you need to identify the positive and the negative points on a battery and we already know that the negative point on the battery is what is the background connection as you see the yellow color line is the GND line of the battery that is traveling all through the mobile PCB so let's keep the probes on one end and connected and now we can hear the beep this basically means that the battery connector negative point is here. if two GND points are connected you will hear the beep sound if not you will not be able to hear a beep sound in these points by segmenting the entire negative line into smaller parts you will be able to exactly trace where the breakages in the entire negative line once the breakage is identified you will then need to use the jumper setting option and try and ensure that the wire is or the circuit is reconnected and is properly functioning
When we check the value of resistance using the multimeter is connected to the ground of the mobile PCB
ground testing

to know more about Ground Line in cell phone PCB read digital multimeter step by step guide article last paragraph

Positive Line VBB or VCC Main in iPhone PCB

now this is how we check the negative line now let's move on to the next part which is a positive line now a positive line cannot be very clearly seen like the negative line the positive line is typically connected to very specific components or ICS and supplies power to each of those components so it's not very easy to identify and it's not open unlike the negative line hence you need to ensure that you are able to trace the positive line effectively after reading through the circuit diagram of the respective iPhone PCB

Mobile Jumper Circuit Diagram Download

unless you have an iPhone Circuit Diagram in hand you may not exactly know how the positive ways is weaved it into the iPhone PCB or into the specific components of the Printed Circuit Broad so please ensure that you pick up their respective surface circuit diagram of the while phone that you are working on understand the VCC main connections that exist in it and then try and trace the connections

+VBAT(battery voltage) on Cell Phone PCBs

now one of the common things that we can do to check the positive ways is to touch the positive terminal +VBAT of the battery connector to this layup capacitor now this component is a very common component that you will find in most cell phone PCBs and this is a common place where the positive ways is usually connected you may be able to identify that in different cell phone PCBs 
check the positive ways is to touch the positive terminal +VBAT of the battery connector
capacitor on mobile PCB

to know more about layup capacitors in mobile PCBs visit How to Check Layup Capacitor in All Cell Phone Circuit
battery voltage +VBAT on Cell Phone PCBs
mobile battery connector pin

once you identify and able to detect that you will be able to touch the positive direct ways in the PCB the positive connector of the battery a connecting point to the specific non polar capacitors, resistance and other components and you can check whether the direct positive ways is intact or not that if there is a breakage here you may not be able to connect or connect the jumper wire from the battery connector VBAT

Step 3 Checking +VBAT(battery voltage) in Cell Phone Circuit

use the back end of the cell phone battery connector as you can see here in the pictures
there's a small point at the back of the battery connector which is connected to the front of the battery connector check whether you are able to get a beep sound
back point is connected to the power point
there's a small point at the back of the battery connector which is connected to the front of the battery connector so you place the one end of the meter prob tip on the back side of the battery connector point and the other on the other connecting point in the pcb and check whether you are able to get a beep sound now here you will be able to connect the jumper clearly without any issues like I just said before in the article the back point is connected to the power point you can hear the beep and from here you can connect the jumper wire to the next point for you to be able to take the positive ways ahead but you need to ensure that you read the phone circuit diagram clearly before you attempt any of this 

phone circuit diagram clearly the first step that you would do while you're testing or tracing the negative and positive ways in a cell phone circuit
power supply system in phone
so, in short, the first step that you would do while you're testing or tracing the negative and positive ways in a cell phone circuit is to understand whether the power supply system in tact and to check

if you want to learn testing or tracing the negative and positive ways faults in iPhone, Samsung PCBs take admission in smartphones problem and their solutions course   

Checking VBAT and GND both Power Supply in Your Cell Phone PCB

check whether the connectivity to the components are then the entire circuit power supply in your cell phone checking can move to further detailed
pcb diagram of mobile phone
that the first thing that you would do is check the negative line(GND) or ground which is signified by the yellow strip that you see all through you can place the probes of the multimeter at two different points or smaller segments of each of these and try and see if the connectivity is intact once that is done you can move on to the positive terminal VBAT of the battery connecting point and try and place it at the respective positive terminals of each of the components to check whether the connectivity to the positive terminal from the VBAT of the battery connector to the individual positive terminals of components are intact or not if these two are intact then the entire circuitry power supply in your cell phone is working absolutely fine once you do this checking you can then move on to do further detailed

Cell Phone Power Section

The top portion near to antenna of the cell phone circuit is called the networks section, and the bottom portion in the PCB is called the power section. Now check the cell phone power section polar and non-polar capacitors, coils, or the power clock oscillator function-specific components near the power IC when cell phone won't switch on.

What Do You Do When a Smartphone Won't Turn On?

in a smartphone, this is a common issue. to fix this in smartphone try to long press the Power Button. in many cases, the power button won’t work because the phone is basically frozen or Historically, the solution is to remove the battery, wait for 10 seconds, then reinsert the phone battery and press the power button again. This removes all the power internally form the smartphone circuit. first, try this to fix the problem. just hold down the power button for ten seconds. If this method doesn’t work, try to press the power button for a bit longer. ten seconds should be suitable for most smartphones, Many smartphones have a method to restart usually by holding down specific keys or buttons on the phone. Much like the Sony Experia and Motorola battery pull where you hold the volume down key and power key simultaneously while the mobile is powered off. Try using a laptop or car charger instead can put a quick charge on phone battery and get it to respond as well. If you have tried these methods and phone isn’t responsive due to its battery drained 100% Try charging it using a battery booster(12 volts DC adopter with Ampare) this device is used to boost mobile phone batteries if you don't know how to use this device to fix the dead cell phone batteries read digital multimeter step by step guide article DC Current Measuring topic.
phone power on after boosting the battery with the battery booster
phone turn on vibrate
If smartphone power on after you boost the phone battery with the battery booster, but boot process fails,
the android phone is freezes on the startup screen, or it immediately reboots or shuts off there is a problem with phone software
stuck on logo samsung
the phone is freezes on the startup screen, or it immediately reboots or shuts off there is a problem with device’s software. In this case, you have to perform a factory reset of your Android smartphone form recovery mode. Note that will erase the data of customer phone to reset it back to phone default software state. you can also use this method when someone smartphone is unusable due to crashing or freezing software.
to perform the factory reset from recovery mode turn the phone off  then boot it up with one of the following button combinations:
Hold Volume Up + Volume Down + Power.
Hold Volume Down + Home + Power.
Hold Home + Power.
If none of these button combinations work, try performing a Google search by typing android phone name and hard reset keys to find the correct key combination of customer device. for example
(Samsung s3 hard reset keys)
perform a factory reset of your Android smartphone form recovery mode
android boot recovery mode
press the key combination until the Recovery mode option appears on the phone screen.
Note that will erase the data of customer phone to reset it back to phone default software state
samsung factory reset code
then Select the wipe data/factory reset option.
Choose wipe data/factory Reset option using volume keys and hold the Power button to enable
performing hard reset
Select the Yes to continue.
If your phone is screen locked you can do a Factory Reset Select the Yes to continue
hard reset screen
if smartphone refuses to switch on normally after performing hard reset try to flash it.
you can't enter into the menu with your google account or if you have a problem with the OS
refuses to switch on normally
if smartphone refuses to switch on after flashing it may be broken inside. then performing a Google search by typing android phone name and service manual to find the phone schematic diagram. then check VBAT and GND both Power Supply in smartphone PCB with the help of the schematic diagram.
I think to learn about jumper settings and how do we do the jumper settings on phone PCBs one article is not enough for you to understand the process for identifying where the circuit is broken in the negative and positive line of a mobile PCB in Dead, Not Charging, Battery Consumption, Auto-Off, water Damaged, Fallen Damaged, NO Vibration, No Tones, No Network, No Ear speaker Voice, No Mic Voice, LCD Disappear faults.
I will tell you those faults step by step jumper setting  in my next article so keep visiting my blog,
I hope you would have understood how to test positive and negative power supply in your cell phone PCB and we hope that you will continue to keep learning more about how to repair cell phone prints
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