Faults in each part, component or section of a mobile cell phone can be repaired fast by using following 2 methods at the time of repairing mobile cell phone. These methods can also be used to find out faulty or damaged parts or components inside a mobile cell phone.
Cold Testing Method:
When we check the value of resistance using a multimeter at the time of repairing a fault in any mobile phone, it is called cold testing. There is no need to give any power supply to the faulty mobile phone from any equipment such as DC Power Supply or battery during cold testing. Diode Range and Beep Sound from the multimeter is used to find fault in a mobile cell phone using the cold testing method of mobile phone repairing. In this testing method, the RED Probe of the multimeter is connected to the ground of the mobile phone PCB and the BLACK Probe is touched at the testing points of the mobile phone. During the fault finding and repairing process of each part, component or section, following correct values will be received:
- Ear Phone Connector Tip (+ , -): .500 to .700
- Loud Speaker / Ringer Connector Tip (+,-): .300 to .600
- Battery Connector Tip (+): .400 to .500
- Battery Connector Tip (Sense): above .800
- Display Connector Supply Pins: .250 to .400
- Display Connector Signal Pins: .500 to .800
- Camera Connector Supply Pins: .250 to .400
- Camera Connector Signal Pins: .600 to .900
- Key Tip (Row and Column): .400 to .800
- Charger Connector Tip: .600 to .700
- Vibrator Motor Connector: .40 to .500
- Power ON / OFF Switch Point (+): .600 to .900
- MIC Connector Tip (Analog MIC) (+,-): .700 to .900
- Battery Charging Out Point (+,-): .300 to .400
- SIM Card Connector Pin 1 (VSim): .500 to .700
- SIM Card Connector Pin 2,3,6: .400 to .800
- SIM Card Connector Pin 4 (GND): .00 (Beep)
- Micro SD Card Connector Pin 4: .500 to .600
- Micro Card Connector Pin 6 (GND): .00 (Beep)
- Micro Card Connector Pin 1,2,3,5,7,8: .600 to .800
- RTC: .400 to .500
- Data RX and TX Pins: .600 to .700
Hot Testing:
This is the second method of fault finding and repairing any mobile cell phone. Hot testing method of mobile phone repairing is adopted when the fault cannot be found or when the phone cannot be repaired using the Cold Testing Method. In this method, VOLTAGE of damaged part, component or section of a mobile phone is checked. The fault is found by giving Power Supply to the mobile phone with a Battery of DC Power Supply Equipment such as DC Power Supply. In this method, DCV (DC Volt) range of the Multimeter is selected. The BLACK Probe of the multimeter is connected with the Ground of the Mobile Phone PCB and the RED Probe is touched at the Testing Points. During Hot Testing method, Voltage of different part or sections should be as follows (All Values in Volt):
- Ear Phone Connector Tip (+ , -) during working: .0 to 2.5
- Loud Speaker / Ringer Connector Tip (+,-) during working: .0 to 2.5
- Battery Connector Tip (+): 3.7
- Display Connector Supply Pins: 1.8 to 2.9
- Display Connector Signal Pins During Working: .0 to 1.8
- Camera Connector Supply Pins: 1.8 to 2.9
- Camera Connector Signal Pins During Working: .0 to 1.8
- Key Tip (Row and Column) One Side: 1.8 to 2.8
- Charger Connector Tip: 5 to 6
- Vibrator Motor Connector Tip During Working: 1.9 to 3.6
- Power ON / OFF Switch Point (+): 3 to 3.6
- MIC Connector Tip (Analog MIC) (+,-): 1.8 to 3.0
- Battery Charging Out Point (+,-): 3.7 to 4.2
- SIM Card Connector Pin 1 (VSim) When SIM Connected: 1.8 to 3.0
- SIM Card Connector Pin 2,3,6 During Working: 0 to 2.8
- Micro SD Card Connector Pin: 2.8
- Micro Card Connector Pin 1,2,3,5,7,8: 0 to 2.8
- Data RX and TX Pins: 1.8 to 2.8