Phone can receive calls, but plug in the charger is not charging properly react.

1 plug, tail damage. by measuring the tail plug CN202 17th, 18 foot (the rightmost two foot) voltage (6~9V) to determine position, if there is no voltage or low voltage (charger under normal circumstances), you have problems at. clean or replace the plug can be resolved (see Figure 1).

2, bad charging circuit. U105 ④ foot is high level, DCIN charging instructions signal to the CPU of the N4 feet, makes CPU output charging display signals. plug in the charger the charging status U105 ④ feet measured under voltage, its normal to around 3V. to 0V, U105 and aim at measuring the foot again. (RTC-3V3) voltage. If no voltage 3.3V section, note U104; if 3.3V works, focusing on search U105, R116, R117 and thrust the 18th foot (DCVOLT) to copper foil circuit breaker between the R116, can fly lines to solve if circuit breaker (see Figure 2).

3 VF, battery testing end the way. this port directly communicates with the CPU, if a failure open circuit there will be no charge, but does not affect the boot. method for determining whether the port is open as follows.

(1) the shutdown state, inserted batteries. by end plug with the charger, if the display is instantaneous, stating that the terminals are left open, unable to communicate with the CPU.

(2) power on State, when you plug in the charger can hear "Ding-Dong" sound, but charge-free response, unplug the charger, there are "Ding-Dong" sound. then check VF with lines between the CPU and the related element is open circuit (see Figure 1). Note: battery failure occurs the same symptoms.

4, battery voltage detection circuit anomaly.

R119, and R122 appeared fault Shi also will appeared not charging, at CPU will made errors judge, think battery has full therefore cannot for charging has. judge method is will a only with models phone in the only left a grid electric of battery put people fault phone, if indicates full electric, is description battery voltage detection circuit has problem, General replaced R119, and R122 can (see Figure 3); but if is CPU, and software appeared problem, also will appeared above phenomenon.

5 other. If the charging indication could not hold the battery is fully charged, can focus on perimeter of resistive and capacitive components U107, Q101 C121, C128, these components of aging or failure