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Display troubleshooting 1
Display
faults
Set phone into local mode.
Set VBATT 4.2 V
Start Display test with Phenix
Set display, keypad lights ON
keyboard
led's turned on ?
Yes
Display
faults 2
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Keyboard LEDs
No
Measure
DC voltage
from X303 pin. 2.
Is it 4.1V ?
No
Measure
DC voltage
from N320/pin 7
Is it ~4.2 V ?
Yes
Check VBAT line
N320/pin 1, C322,
R326, C327, C320,
C321, C325.
If OK, change
N320
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Replace
keyboard
Yes
module
now OK ?
No
Check X303
Yes
Measure
DC voltage
from C328
Is it ~0V?
No
Check line to UEM
(KLIGHT line must be in
LOW state when lights on
No
and in high impedance
state when lights off)
IF OK –>
change UEM
Check R325
N320 and
CALLED1 line
to UEM
1+0
Retest
Check R313,
C328 and
line to X303
Yes
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