5. Troubleshooting process for “Power not on” is shown in the figure 3.3.2.5:
Power not on
Whether
3.3V output is normal
Whether
5V input is normal
Check whether Q8 is
normal
Whether
1.8V output is normal
Check U3 and circuit
around
Whether
load is too heavy
Check U1 and circuit around
BGA has trouble
Check BGA working
conditions
Figure 3.3.2.5 Power management circuit troubleshooting flow chart
N
N
Y
N
N
Y
N
Y
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Summary of Contents for X21
Page 1: ...service manual X21 RU ...
Page 42: ...3 L1 1 8V energy storage waveform diagram 4 LCD_CS wabeform 5 LCD_D C waveform diagram 37 ...
Page 43: ...6 LCD_RESET 7 LCD_WR waveform diagram 8 LCD_RD waveform diagram 38 ...
Page 45: ...12 LCD_DB3 waveform diagram 13 LCD_DB4 waveform diagram 14 LCD_DB5 waveform diagram 40 ...
Page 46: ...15 LCD_DB6 waveform diagram 16 LCD_DB7 waveform diagram 17 IREF waveform diagram 41 ...
Page 47: ...18 VCOMH waveform diagram 42 ...
Page 66: ...Chapter Cinque PCB board Circuit diagram Section One PCB board X21 PCB Board 61 ...