Panasonic SA-PT250GCP, Service Manual

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21 Basic Troubleshooting Guide
21.1. Basic Troubleshooting Guide for Traverse Unit (DVD Module P.C.B)
Problems Checking Points Checking Components
a) Check SDRAM address,
data bus, CLK and other
control signals waveform IC8051
b) Check video signals LB8301, R8321, R8322,
LB8302, R8325, R8326
1) Distorted picture or
abnormal sound is head
during the initialization
c) Check audio DAC circuitry
* Compare the above with
OK condition DVD
module P.C.B.
IC8421
*Check for solder short
and/or component
missing/damaged
a) Check motor driver
circuitry (+5V) IC8251 Pin 8, 21
b) Check laser drive
circuitry (Voltages &
current) Q8551, Q8552, Q8561,
Q8562
2) No TOC / Long TOC
c) Check LSI IC connection
to motor drive circuitry
*Compare the above with
OK condition DVD
Module P.C.B.
IC8001 Pin 66, 67
* Check for solder short
and/or component
missing/damaged
a) Check connection from
DVD Module to Traverse
unit FP8251 3) Disc not spinning
4) Traverse not moving
5) Traverse and spindle
abnormal movement
b) Check motor driver
circuitry on the voltages and
control signals
*Compare the above with
OK condition DVD
Module P.C.B IC8251
*Check for solder short
and/or component damaged
6) Cannot read the disc but
spindle motor is spinning
- Cannot read CD/DVD
a) Check laser drive
circuitry (voltages
and current)
- Check CD Laser
Drive
- Check DVD Laser
Drive
* Check voltages and LD
current and compare with
OK condition DVD
Module P.C.B.
Q8551, Q8552, LB8531
(For DVD Laser Drive
current)
Q8561, Q8562, LB8561
(For CD Laser Drive
current)
7) Block Noise during play a) Check SDRAM address
and data bus signal IC8051
8) Jitter out of specification
9) Cannot read data from USB
a) Check LD current
b) Check OPU
a) Check USB connector & FFC
b) Check LSI O/P
c) Check IC supply (+5V)
(Change to other unit and
confirmed operating
condition)
OPU Unit (Traverse unit),
FPC connection
FP9001
IC8001 Pin 144, 146
IC9005 Pin 2, 3
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SA-PT250GCP