LG ID2750 Service Manual page 34

4.1.5 Checking Control Signal
Test Point
U104. 5 (SBST)
Checking Flow
Check Pin 3, 4, 5
◆ Refer to Graph 4-3(a,b)
Check SBDT, SBCK SBST
Check if there is
Any Major Difference
◆ Refer to Graph 4-3(a,b)
Waveform
SBDT
SBCK
Graph 4-3(a)
U104. 4 (SBCK)
Figure 4-5
No
Level is High?
Yes
No
Similar?
Yes
Control Signal is Ok
See next Page to check
Duplexer
U104. 3 (SBDT)
Download the SW
Download the SW
SBST
SBCK
Graph 4-3(b)