Daewoo DP-42GM, Service Manual

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10. TROUBLE SHOOTING
10-1. Facts you must know when Trouble diagnosis or repairing
(1) Set s trouble diagnosis and repairing means Module Exchange . In other words, find out
which PCB modules are not working and replace them with normal PCB modules. Do not need
to fix broken PCB modules in themselves.
(2) This TROUBLE SHOOTING list only contains representative and simple PCB trouble
diagnosis and Module Exchange method. Therefore, if you find Sets that are difficult to
diagnose or to repair, contact Daewoo Electronics.
(3)Basic TROUBLE SHOOTING procedure
Check Trouble Symptom Detach BACK COVER Trouble Diagnosis replace broken
PCB module Adjust new PCB module ( when replacing X-SUS, Y-SUS, POWER, VIDEO
PCB, need Adjusting Prodedure. Refer to 6. Adjusting Method ) HEATRUN (for at least 30
minutes, input TEST PATTERN FULL WHITE), FUNCTION CHECK Repair Complete.
(4)Keep broken PCB modules separately for replacing with new PCB modules.
(5)Required equipments for trouble diagnosis
- DIGITAL MULTIMETER (User Mode : measure DC VOLTAGE, measure DIODE
VOLTAGE, SHORT-OPEN TEST )
- Screwdriver (or electric screwdriver), plastic adjusting tool
(6) Each BLOCK operation was explained including DIGITAL OSCILLOSCOPE signal, but this is
reference only and applying them for repair is not necessary. (After additional education,
DIGITAL OSCILLOSCOPE could be used)
(7) Before assemble/disassemble PCBs, check to see if AC Switch is OFF .
(8) After replacing X-SUS, Y-SUS, POWER, VIDEO PCB, the PCB, needs extra adjustment.
(Refer to Service Manual 6. Adjusting Method)
(9) After the set is repaired, leave BACK COVER open for followings. Do HEATRUN for at least
30 minutes by inputting SERVICE MODE s TEST PATTERN (Refer to Service Manual 5.
Service Mode) FULL WHITE. Check the screen condition and basic functions (remote control
operation etc.).
(10) After BACK COVER is closed, redo HEATRUN for at least one hour by inputting FULL
WHITE using SERVICE MODE s TEST PATTERN. Check the screen condition and basic
functions.
10-2. Typical Symptoms of PCB s Trouble or bad CONNECTION
(1)Symptoms of X-SUS or Y-SUS PCB s Trouble
<Symptom.1> Not even weak discharge (luminescence) shows on screen.
<Symptom.2> Discharge (luminescence) on screen is unstable (refer to Trouble
Symptom Picture<8> )
<Symptom.3> Set is producing unusual noise.
<Symptom.4> POWER SHUT DOWN occur ( refer to Service Manual 10-3 )
(2)Symptoms of SCAN PCB Trouble