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8. Level 3 Repair
8-4-1. Power On
Check the signal of
TRST_N = 1.8V
Mobile phone does not power on.
Yes
No
No
Charging the battery by TA.
If its voltage level is extremely low
(under 3.0V),
Change the battery.
Yes
No
END
Yes
No
Power-on the phone and check
the power-on sound
or motor Vibration.
Sound or Vibration is ok?
Yes
Change the FRONT-LCD ASSY
No
Check the voltage level at
R3005 while pressing power
key. Is the voltage lower than
0.3V?
No
Replace the Power key FPCB
Yes
No
No
Check the output voltage of U5003
C5032 > 3.3V,
L5000 > 1.1V, L5002
> 0.9V, L5003 > 0.9V, L5007
> 0.9V, L5008 > 0.9V,L5010 > 0.9V,
L5009 > 1.3V and other LDO Voltage
If the output voltage is abnormal, Change
the U5003
※
Each voltage level has ±10% margin
Yes
No
No
Replace the U5004
※
Test condition (Oscilloscope setting)
: 20.0us.div (time division)
Yes
No
Check the initial operation
Check the Battery Voltage.
Is it more than 3.8V?
Check the signal of SLEEP_CLK
Is the frequency 32.768kHz?