Fld Display Check - LG CJ44 Service Manual

ELECTRICAL TROUBLESHOOTING GUIDE

4. FLD DISPLAY CHECK

FLD DISPLAY CHECK
YES
Check
CN102 Pin13,14 input
voltage.
YES
Check if both end voltage of F+, F- are over 1.85 V
VH : over 27 V.
YES
Check
CN300 connection and
power Pin14, 16,17
(VIN, F+, VDD).
YES
Check
VFD300 voltage Pin27,
26, 31, 32 VH: over 27
V, SW Signal, F- : over
3 V is OK?
YES
Check
IC500->VFD300 data
communication STB/
DATA/ CLK
YES
FLD light on?
YES
OK OK
NO
Refer to SMPS troubleshooting.
NO
Check CN300 connection.
NO
If voltage isn't over VH : 27 V, F- : 3 V
and, SW signal is not operation?
Check VFD300.
OK
NO
Check input data
IC500 Pin F2, B3, B1.
Check output data IC500 Pin B3.
Check IC500.
OK OK
3-21
NO
YES
NO
YES
YES
YES
NO
YES
Check each Pin voltage.
YES
OK
Replace VFD300.
Replace IC500.