Pioneer PDP-42A3HD Training & Troubleshooting Manual page 72

CHANNEL INSPECTION 2
Channel Inspection
No Channel Locking with No Problems with Power/CPU
Preliminary Checkpoints
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
* +5VDT of PIN 3, 7
* PIN48 [SCL] of LGDT3303
* PIN49 [SDA] of LGDT3303
* VIN+
* VIN-
* PIN22(TUNER_AGC)
of LGDT3303
* PIN46(VSB_CLK) of
LGDT3303
high : lock
low : unlock
* VSB_D [7 : 0] of
LGDT3303
Channel locking failure
Check the TUNER power
OK
Check the 12C DATA and
CLOCK of TUNER
Waveform 15
OK
Check the TUNER output
(VIN+, VIN-)
Waveform 16
OK
Check the TUNER
AGC
Waveform 17
OK
Check the output of Pin46
is high, also check clock
and valid of LGDT3303
OK
Check the TS DATA output
and goes to CPU
Check for other defective
modes
After the basic inspection, check the
NG
path between SMPS and TUNER
(Incorrect insertion, poor soldring, short
Check the path between
NG
CPU and LGDT3303 (Incorrect
insertion, poor soldering, short
Check the path between
NG
LGDT3303 and TUNER (Incorrect
insertion, poor soldering, short
Check the path between
NG
(Incorrect insertion, poor soldering,
short circuits, damage, etc.)
NG
Replace the related parts
NG
Replace the related parts
72
circuits, damage, etc)
circuits, damage, etc.)
circuits, damage, etc.)
LGDT3303 and Tuner
(demodulator)
(demodulator)