LG GX500 Service Manual page 76

GX500 Operational Description
GX500 Operational Description
Checking Flow
Checking Flow
START
START
Connect power
supply to the DUT
Vbat = over 3.35V
Connect power
supply to the DUT
Vbat = over 3.35V
"PWRON" signal
Check 3 pin of U203
"PWRON" signal
Check 3 pin of U203
Check the all LDO's
output
Is it correct?
Check the all LDO's
output
Is it correct?
Is the 26MHz
clock From X401
signal correct?
Is the 26MHz
clock From X401
signal correct?
Replace main PCB
Replace main PCB
LG Electronics
LG Electronics
Copyright © 2010 LG Electronics. Inc. All right reserved.
Only for training and service purposes
Yes
Yes
No
No
Yes
Yes
No
No
Yes
Yes
No
No
Yes
Yes
Figure 4-5. X-TAL & Transceiver
Figure 4-5. X-TAL & Transceiver
U401
U401
77/143
77/143
Check the RPWRON,
replace Q201
Check the RPWRON,
replace Q201
Check solder
U201 or replace it
Check solder
U201 or replace it
Check solder X401
or replace it
Check solder X401
Check 3 pin of X401
or replace it
Or Check 11 pin of U401
Check 3 pin of X401
Or Check 11 pin of U401
X401
X401
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4. TROUBLE SHOOTING
Revision A
Revision A
TP1
TP1
Q201
Q201
Figure 4-3. RPWRON
Figure 4-3. RPWRON
14pin of U401
14pin of U401
1pin of X401
1pin of X401
LGE Property
LGE Property
LGE Internal Use Only
U201
U201