Gsm Afc Calibration - Lenovo S930 Service Manual

LENOVO S930 Cellphone Service Manual
dry joint problems.
⚫
Troubleshooting:
Did GSM
frequency band
fail?
Y
Do L2102 and
Re-solder.
C2130 have dry
joint problems?
Y
Does receiving
Re-solder/repl
filter(U2103)
ace couplers.
have a dry joint
problem?
N
Y
Do L2108 and L2109
Re-solder or
have dry joint
replace.
problems?
N
⚫
Note: Normally you need to re-calibrate the corresponding components after the replacement.

4.1.3 GSM AFC calibration

⚫
Problem: APC calibration failed.
⚫
Reason: During the calibration, connections of RF test cable are not reliable; PA module (U2102)
is fitted reversely; PA module and peripheral circuits have dry joint problems; the patches of PA
N
Check the calibration report
to see whether all three
frequency bands failed.
Y
Do L2101 and
C2117 have dry
problems?
joint
N
N
Does receiving
filter U2103 have
a dry joint
problem?
N
Do L2104 and
L2105 have dry
joint problems?
N
Check RF receiver and transmitter
Rx path loss
calibration failed.
Y
Y
Re-solder.
Y
Re-solder or
replace.
Y
Re-solder or
replace.
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N
Check whether
connections of RF cable
and fittings are reliable.
Y
Check whether RF
connector CON2101 has
a dry joint problem.
N
Y
Do R2115 and C2131
have dry joint problems?
N
Re-connect
and
calibrate.
Y
Re-solder
CON2101.
Re-solder.