To sum up, the main phenomenon of mobile phone software failure are:

1. Mobile phone screen display contact service providers, factory maintenance and other information are software failure, rewrite the chip data can be.

2. do not boot, press the power button ammeter indicator current, a lot smaller than the normal value of about 200mA, but release the power button ammeter pointer back to zero, this phenomenon shows the basic part of the power supply, the clock circuit is not working or CPU normal work.

3. Do not boot, press the power button ammeter pointer to indicate the current about 200mA pause immediately back to 0mA. This is a typical chip information caused by the disorder of the software does not boot failure

4. Press the power button to talk about 20 ~ 30mA leakage current, indicating that the power part of the components short circuit or damage.

5. Press the power button to have a large current leakage indicates that the power supply part of the short circuit or the power amplifier part of the damage to components.

6. With the battery on the leakage, first remove the power metering block, if not leakage, indicating failure caused by the power IC; if still leakage, indicating that the battery directly from the battery directly powered components damaged or its own short circuit (water Prone to this failure) caused. According to the battery to the principle of mobile phone power supply to find the line or components (power supply filter capacitor, power supply protection diode sometimes short circuit).

7. The phone can work, but the standby state is much larger than the normal situation. This troubleshooting method is: to the phone power, 1 to 2 minutes around the back to feel which components to heat, to replace, in most cases, can be ruled out the fault. Such as still can not be excluded, to find its heating components of the load circuit is damaged or other components of the power supply components are damaged.

8. No signal strength indicator or no network, according to the ammeter pointer swing to determine the approximate range of the fault. Under normal circumstances, the phone looking for the network at the same time, ammeter pointer constantly swing, the amplitude of about 10mA. If the ammeter pointer swing normal, there is no network, this failure more common in Nokia, Motorola and other mobile phones, most of the range of the transmission part of the VCO or amplifier circuit part; if the ammeter pointer is not normal and no signal strength instructions, the fault range mostly in Receive VCO, local oscillator part or other part of the receiving channel.

From    ananda    10 years of international brand refurbished mobile phone export