How To Use DC Power Supply

How to use DC Power Supply in Mobile Repairing?

You can use DC power supply mobile repairing to check four things in your customer’s phone

1. customer’s phone is dead or not
2. customer phone circuit is a short circuit or not
3. customer phone circuit prints are open or not
4. customer’s phone has a software problem

connecting examples

Watch how to connect mobile phone with DC Power Supply GIF Demonstration here. Set DC power supply Voltage to 3.7 and Ampere to 150 to check the feature phone.

Set DC power supply Voltage to 4.1 and Ampere to 200 to check smartphone.

If you are connecting the Tablet then set the switch supply Voltage to 4.2 and Ampere to 200.

Now switch ON the phone and see Ampere Reading. 

Note: If the Ampere does not show any reading it means your phone power input track on the battery connector is open.

2. Customer Phone Circuit is a Short Circuit or Not 

Reasons for short circuits in mobile phone circuits:


1, Phone falling into toilet water or liquid damage. this is the most common reason that mobile phone users are facing in routine life.

2, The smartphone is warming again and again.

3, Using an incompatible or faulty phone charger for charging the battery. also when you use the wrong charger to charge your phone it gets hot.

4, Sometimes due to any reason phone has fallen down or crashed.

To check the mobile phone short circuit with the dc power supply follow the steps below: 

step one: Set DC power supply output voltage to 3.7v or 4.1 volts.

step two: Connect the red wire to the positive terminal of the battery connector (+VBAT pin) and the black wire to the negative terminal (GND)as well as the 3rd pin called the BSI battery status interface.

DC Power Supply Reading

Reading one: Now, if you see any amount of ampere on the screen, without you pressing the phone power button then it means, the mobile phone is a short circuit.

half short circuit

cell phone circuit track is open

Phone Circuit Prints are Short Circuit: if 2 parallel separate Prints positive and negative touch each other due to a fault in the mobile phone PCB, it is called a short circuit.

component goes short

Note: In PCB boards of mobile phones, smartphones, and tablets there is the print instead of copper wires through which DC current flows. Hence we use the term ‘Prints’ instead of copper wires or cables.

Now let me tell you the Problems of the short circuit in smartphones:

1, When you switch ON the phone, it goes switch OFF automatically after a few minutes.
2, The phone goes completely dead.
3, Phone battery drains and discharges fast.
4, The phone goes hot and the get Hang.

Note: The above procedure to check short circuit in the mobile phone with DC Power Supply is the same for all Mobile brands and tablets including Microsoft phones, Samsung, Nokia, Apple iPhones, Sony Xperia, HTC, Motorola, Q mobile Vivo, and Oppo handsets. It will be the same for all iOS, Android, or Windows OS smartphones.

4. Customer Phone has a Software Problem 

Set DC power supply output voltage to 3.7 volts on the feature phone and 4.1 volts on the smartphone. 

Connect red wire of the DC power supply connector cable to the positive terminal of the battery connector, and black wire to the negative terminal and the yellow probe to the middle pin of the battery connector of the feature phone. 

In the smartphone connect the power supply cable red wire to the positive terminal of the handset battery connector +VBAT and the black wire to the negative GND as well as the 3rd pin BSI to check the phone.

Now switch ON the phone and see Ampere reading. if you see 003 or 005 amperes on the screen, when you press the phone power button then it means, the feature phone software is corrupt.

In the smartphone, you see at ampere reading screen 010 or 015 when you press the power button of the phone if the phone is in software fault.