good day,
basic repair vcc main short tracing
step 1. basic test remove battery insert supply para mabasa current reading, set 4.2 volt... current exceed to more than 3amp... drop voltage sa 2v... sure short
2. test off line diode mode or buzzer using dmm... digital multimeter vcc main short.... confirm
3 tracing which component.... using volatage injection makikita ang shorted line.... inject lang ako sa vcc main ng 3v... 2amps using bench supply.... by the help of rosin smoke makikita ang melting area na umiinit at component pero hindi ibig sabihin ayun ang problem agad..
4. overheating switching ic.... inangat ko test sa pads.... na inalisan shorted ang 4.2 line... sundan ang mga group ng component inject again at lumabas ang 2g band ic inalis ko na at binalik ang electronic switch ic... done
basic repair vcc main short tracing
step 1. basic test remove battery insert supply para mabasa current reading, set 4.2 volt... current exceed to more than 3amp... drop voltage sa 2v... sure short
2. test off line diode mode or buzzer using dmm... digital multimeter vcc main short.... confirm
3 tracing which component.... using volatage injection makikita ang shorted line.... inject lang ako sa vcc main ng 3v... 2amps using bench supply.... by the help of rosin smoke makikita ang melting area na umiinit at component pero hindi ibig sabihin ayun ang problem agad..
4. overheating switching ic.... inangat ko test sa pads.... na inalisan shorted ang 4.2 line... sundan ang mga group ng component inject again at lumabas ang 2g band ic inalis ko na at binalik ang electronic switch ic... done