3. Trouble Shooting
3.1 Fail to startup/power on
The following conditions may cause boot fail: battery low, battery connector is damaged or
bad welding, components bad weld/short-circuit or damaged
First, change a fully charged battery test, still startup fail, check battery connector ok or not,
if connector damaged change a new one;
Second, connect to DC power supply, if the boot process is no current, we should check
power key solder ok or not;
Third, if the boot current is very small and cannot maintain ,connect the power on test point
to GND, then check below voltage in sequence,
BBWAKEUP
，
VRTC
，
VPROC(VCORE,VSRAM)
，
VSYS
，
VIO18/VEMC3V3
，
VA28/VIO28
，
VM
，
VUSB
，
VMC/VMCH,
VTCXO, RESETB ok not.
Fourth, if the current stay in 80mA, we should check the circuit around flash, when CPU
calling program from flash fail, the current will stay in 80mA, re-download the software or
change a new flash or CPU.
Fail to power on
Check
if
the
battery is OK.
Change
battery
Check if battery
connects solder ok
Is power key OK?
Check
each
power out of PMU
Resold
connect
Change a new
power key
Re-solder or
replace U1420
Re-download
Software
OK
Y
N
N
N
N
Y
Y
Y
Y
OK
N
Y
N
Resold
or
replaceU1501
Resold or replace
U200
OK
Y
