LG VX8500 Service Manual page 78

VX8500
Checking Flow
Start
Check U108 Pin21
PCS_OUT
Refer to Graph4.2.2.4 (A)
YES
Similar?
NO
Check U108 I/Q Data
Pin27. 28, 29,30
Refer to Graph4.2.2.4 (B)
Similar?
YES
+2.6V_MSMP PIN 32
Check U108 Pin1, 12,24
+2.9V_TX
+2.6V_MSMP2
PIN : 6,9,13,14,17,19,20,22,24,25,31
+2.9V_SYNTH
OK?
YES
Check U108 Pin1
(TX_ON Signal)
≥2.5
YES
LG Electronics Inc.
RFT Circuit is OK
See next page
NO
Check U201 MSM
NO
Check Regulator Circuit
NO
Check TX_ON
Signal Line&MSM
86
YES
Check U108 Pin15
TCXO
Refer to Graph4.2.2.4(C)
NO
Similar?
YES
Check U108 Pin2, 3,4
SBCK0
SBDT0
SBST0
Refer to Graph4.2.2.4 (D)
Similar?
YES
Replace U108
Check TCXO Circuit
Check SBI Signal
Line&MSM