LG H990ds Service Manual page 47

3.6.6 TD-SCDMA PART – B34/B39 Tx
Checking Tx signal path(TD-SCDMA B34/B39 Tx)
START
Check TP1/TP3
+VPA0 OK?
YES
Check TP2
3.2V≤TP2≤4.2V?
YES
Check TP4
If LTE of All band
Over 22dBm?
NO
Check TP4
If LTE of All band
Over 10dBm?
NO
Check
Transceiver
physical damage
or soldering
condition
OK
Check next step
LGE Internal Use Only
Checking Flow
The Problem may be
other part and
Check QFE2101 Logic part
NO
The Problem may be
other part and
NO
Check QFE2101 Logic part
Check component
above RF signal path
YES
and FEMid Block
Replace U1301
YES
NOT GOOD
Replace U1400
TP2(+VPWR_BOOST_BYPASS_RF)
U1601
U1301
(MMPA)
TP3(+VPA0)
47
3. TROUBLE SHOOTING
Image
TP1(+VPA0)
TP4(B34/39 Tx)
BOTTOM
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