Trouble Shooting - Daewoo DPP-42A1GCSB Service Manual

11. Trouble Shooting

Before starting Trouble Shooting
Trouble diagnosing and repairing of set mean find out which PCBs or blocks are
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not working and replace them with new PCBs.
Repairing the broken PCBs are not necessary. Keep the broken PCBs and return
them to service center or R&D center.
This Trouble Shooting list only contains representative and simple PCB trouble
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diagnosis and Module Exchange method.
Therefore, if you find sets that are difficult to diagnose or to repair, contact R&D center.
Basic Trouble Diagnosis procedure
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1) Check problem Symptoms
2) Open Back Cover
3) Trouble Diagnosis & Replace broken PCB
4) Adjust new PCB module
5) HEATRUN for at least 30 minutes, inputting Full White test pattern
6) Full Function test
7) Repair Complete
Required Equipment for trouble diagnosis
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1) Digital Multimeter(User Mode : measure DC Voltage, measure Diode Voltage,
Short-open test)
2) Screwdriver(or electric screwdriver), Plastic adjusting tool
3) Oscilloscope(for detailed examination only)
Before replacing PCBs, you MUST turn the AC switch "OFF".
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After replacing High Voltage Board(Power PCB, Y-SUS, Z-SUS, Data B/D, Scan B/D),
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and Main & Sub PCB, extra adjustment might be needed.(Refer to Power Adjustment)
Dust or extraneous materials may cause bad connections.
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Therefore, try to apply soft brush, air fresher, or breath to clean the dust or
extraneous materials.
While assembling the set in factory, it could have bad connection.
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Try to reassemble the necessary connectors and also check the state of the connectors.
After the set is repaired, leave Back Cover open for followings.
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Run HEAT RUN for at least 30 minutes by displaying Full White test pattern of
Service Mode(Refer to Service Manual '6. Service Mode' part).
Check the screen conditions and basic functions(remote control operation etc.)
After Back Cover is closed, redo HEAT RUN for at least one hour with Full White
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input using Test Pattern of Service Mode. Check the screen conditions and basic functions.
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