Channel Inspection - Pioneer PDP-42A3HD Service Manual

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7.1.8 CHANNEL INSPECTION

Channel Inspection
No Channel Locking with No Problems with Power/CPU
A
Preliminary Checkpoints
If channel locking fails even though there is no problems with the system, check
the Interface between Tuner, LGDT3303 and CPU.
B
- LDGT3303 Input Power
* +3.3V
Pin21, 35, 61, 93
* +1.8V
PIN16, 19, 32, 42, 47, 55, 63,
68, 74, 81, 85, 89, 100
C
- LDGT3303 PIN26
* low : reset on
* high : reset release
- LGDT3303 Pin 79, 80
* 25MHz clock
D
- 12C CLOCK [PIN48]
- 12C DATA[PIN49]
E
Useful Tips
1. Check the power byU532 are properly provided to the U531.
2. Check the 12C interface between tuner and 10046. If no problem, inspect along the tuner output path to TDA10046.
Whether the components of R, L, C's soldering status.
3. If no problem, replace the Tuner.
4. If the problems are founded by CPU, replace the CPU board and also download SN.
F
T23
100
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2
Channel locking failure
Check the LGDT3303
input voltage
OK
Check the LGDT3303 input
(Reset) = high
Waveform 14
OK
Check the LGDT3303
input clock
OK
Check the 12C control
Check other related
part
PDP-42A3HD
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3
After the basic inspection, check the
NG
path between U501 and LGDT3303
(Incorrect insertion, poor soldering,
short circuits, damage, etc)
Check the path between
NG
CPU and LGDT3303 (Incorrect
insertion, poor soldering, short
circuits, damage, etc.)
Check the path between
NG
LGDT3303 and X-Tal (Incorrect
insertion, poor soldering, short
circuits, damage, etc.)
Check the path between
NG
devices the LGDT3303 and EEPROM
Also, check Incorrect insertion, poor
soldering, short circuits, damage, etc.)
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4
T23
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