4. TROUBLE SHOOTING
- 90 -
CHECKING FLOW
START
Check Battery Voltage
> 3.35V
Push power-on key
And check the level change
of PWRKEY
Check the voltage of
The LDO outputs at U100
Logic level at KEYON signal of U100
= HIGH?
Does it work properly?
THE PHONE WILL
POWER ON.
Charge or Change Battery
Check the contact of power key
Or dome-switch
Replace U100
VCORE=1.8V VVCXO=2.75V
VMEM=2.8V
VSIM=1.8V or 2.85V
VEXT=2.8V
VABB=2.75V
VMIC=2.5V
Re-download software
The power-on procedure is
Completed. The problem may
be elsewhere.
Does it work properly?
Replace the main board
YES
YES
YES
YES
YES
NO
NO
NO
NO
NO
NO
Figure 4-27.
Summary of Contents for KG920
Page 3: ... 4 ...
Page 48: ...3 TECHNICAL BRIEF 49 3 8 2 AFE Analog Front End Figure 3 22 ...
Page 52: ...3 TECHNICAL BRIEF 53 3 8 5 MBGM01 5M CCD ISP Figure 3 25 ...
Page 55: ...3 TECHNICAL BRIEF 56 3 8 6 MV8620 5M back end IC Multi Media Function Figure 3 26 ...
Page 58: ...3 TECHNICAL BRIEF 59 3 9 MIDI IC YMU787 Figure 3 27 YMU787 BLOCKDIAGRAM ...
Page 108: ...4 TROUBLE SHOOTING 109 CIRCUIT WAVEFORM Figure 4 59 Graph 4 11 Figure 4 60 Figure ...
Page 109: ...4 TROUBLE SHOOTING 110 TEST POINT U602 FB602 U100 Q100 Q101 C113 C114 Figure 4 61 Figure 4 62 ...
Page 112: ...4 TROUBLE SHOOTING 113 Figure 4 67 Figure 4 68 CIRCUIT ...
Page 115: ...4 TROUBLE SHOOTING 116 WAVEFORM Graph 4 13 ...
Page 139: ...6 BLOCK DIAGRAM 140 6 BLOCK DIAGRAM Figure 6 1 ...
Page 148: ... 149 8 PCB LAYOUT ...
Page 149: ... 150 8 PCB LAYOUT ...
Page 150: ... 151 8 PCB LAYOUT ...
Page 151: ... 152 8 PCB LAYOUT ...
Page 152: ... 153 8 PCB LAYOUT ...
Page 153: ... 154 8 PCB LAYOUT ...
Page 154: ... 155 8 PCB LAYOUT ...
Page 155: ... 156 8 PCB LAYOUT ...
Page 163: ... 164 ...
Page 194: ...Note ...
Page 195: ...Note ...