LG VX8610 Service Manual page 84

VX8610
Check pin2(TP1),7(TP2) at U108
Check if there is any major difference referring
To Figure 4.2.2(i) Is it similar?
Check pin4, 12(TP3) at U108 ( Vcc)
whether it is higher than 3.4V.
Check pin4 at U108(PA_ON2 signal)
Check pin3(TP4) at U108(PA_R1)
whether it is lower than 2.2V.
RF_IN fed up with CW signal
in low gain mode of PAM
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Only for training and service purposes
Checking Flow
Start
YES
YES
whether it is higher than 2.2V.
YES
YES
Replace U108
Checking Flow
PAM circuit is OK. See next page
YES
NO
NO
NO
Waveform
Waveform
Figure 4.2.2(i)
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Check Vcc line
Check PA_ON line
Check PA_R1 line
RF_OUT
LGE Internal Use Only