CHANNEL INSPECTION 2
If channel Locking fails even though there is no problems with the system, check
the TUNER 12C BUS and IF signals.
If the Tuner 12C and IF signals are good but cannot search, check TS data goes to CPU
Channel Inspection
No Channel Locking with No Problems with Power/CPU
Preliminary Checkpoints
Check the TUNER power
* +5VDT of PIN 3, 7
Channel locking failure
Check for other defective
modes
After the basic inspection, check the
path between SMPS and TUNER
(Incorrect insertion, poor soldring, short
circuits, damage, etc)
NG
OK
Check the 12C DATA and
CLOCK of TUNER
* PIN48 [SCL] of LGDT3303
* PIN49 [SDA] of LGDT3303
Check the path between
CPU and LGDT3303 (Incorrect
insertion, poor soldering, short
circuits, damage, etc.)
NG
OK
Check the TUNER output
(VIN+, VIN-)
* VIN+
* VIN-
Check the path between
LGDT3303 and TUNER (Incorrect
insertion, poor soldering, short
circuits, damage, etc.)
NG
OK
Check the TUNER
AGC
* PIN22(TUNER_AGC)
of LGDT3303
Check the path between
LGDT3303 and Tuner
(Incorrect insertion, poor soldering,
short circuits, damage, etc.)
NG
OK
Check the output of Pin46
is high, also check clock
and valid of LGDT3303
* PIN46(VSB_CLK) of
LGDT3303
high : lock
low : unlock
Replace the related parts
(demodulator)
NG
OK
Check the TS DATA output
and goes to CPU
* VSB_D [7 : 0] of
LGDT3303
Replace the related parts
(demodulator)
NG
Waveform 15
Waveform 16
Waveform 17
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