Blu LIFE 8, Руководство по обслуживанию

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4.2.3 Charge Power On
When the charger is plugged in, the system will also come into a special power on state. It
is detected by the CHRIN of the PMU.
4.2.4 Phone cannot power on troubleshooting
：
1. Measure “VBAT”, if the voltage is right then check the battery or power supply. You’d
better use the power supply to observe the power on current.
2. Check if 32 KHz oscillator is working, otherwise check CPU or change the oscillator.
3. Press the power key and measure the LDO(VDD,VMEM etc) output voltage, if it’s no
right, check CPU, rework or change it.
4. Check if 26 MHz oscillator is right, and need check the parts around it, otherwise rework
or change transceiver IC.
5. Check soldering process about CPU IC, memory IC.
4.3 Audio Part troubleshooting
4.3.1 Speaker Circuit
Because of CPU chipset integrated audio transducer, hardware decoder, and audio amplifier.
The audio PA type is class D which working at high efficiency state.
Audio signals output two channels difference signals from CPU to drive speaker.
If there is something wrong with the speaker function, you should make sure the speaker is
OK? It is resistance is 8 ohms itself. If speaker is OK, then check output signals, if any
soldering process in circuit, If the signals not ok you’d better rework or change CPU IC.
4.3.2 MIC Circuit
Voice be converted to electric signal by microphone then input CPU IC.
If the MIC loop is not working, first, check MIC itself is OK and MIC’s polarity is
correctly, then measure the power supply at calling or recording state, because of the power
supply was turnoff at other states. Check the circuit as flow at last.