Trouble Shooting - Daewoo DPP-42A1LASB Service Manual

11. Trouble Shooting

Before starting Trouble Shooting
Trouble diagnosing and repairing of set mean find out which PCBs or blocks are
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
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
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
1) Digital Multimeter (User Mode : measure DC Voltage, measure Diode
2) Screwdriver (or electric screwdriver), Plastic adjusting tool
3) Oscilloscope (for detailed examination only)
Before replacing PCBs, you MUST turn the AC switch "OFF".
After replacing High Voltage Board (Power PCB, Y-SUS, Z-SUS, Data B/D,
Scan B/D), and Main & Sub PCB, extra adjustment might be needed. (Refer to
Power Adjustment)
Dust or extraneous materials may cause bad connections. 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.
reassemble the necessary connectors and also check the state of the
connectors.
After the set is repaired, leave Back Cover open for followings. Run HEAT
RUN for at least 30 minutes by displaying Full White test pattern of Service
Mode (Refer to Service Manual I. 'Service Mode' part).
conditions and basic functions (remote control operation etc.)
After Back Cover is closed, redo HEAT RUN for at least one hour with Full
Voltage, Short-open test)
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Try to
Check the screen