Daewoo DP-42GM, Service Manual

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Main PCB Trouble Diagnosis
images are displayed.
<2> PCB Check Priority(Left to Right)
- X-SUS, Y-SUS, SCAN, POWER, DATA, DIGITAL, CONN-LEFT/RIGHT
<3> Trouble Repairing Procedure
- First, refer to 6-2 Adjusting Driving Voltage and Waveform to check if each voltage is
adjusted according to Optimum Voltage LABEL . If the there are voltage difference, adjust
voltage according to the Optimum Voltage LABEL and then check the screen.
- If voltages are adjusted correctly, perform trouble diagnosis in the order as shown in FIG<10-
4> and then replace broken PCB.
(3)When Vertical or Horizontal lines (regular or irregular, single or block) occur
<1> Definition of Horizontal Line , Vertical Line
- Horizontal Line/Vertical Line OPEN : Problematic line s electrode or signal line is OPEN, so
it is displayed BLACK.
- Horizontal Line/ Vertical Line SHORT : Problematic line and adjoining lines are SHORTING
each other creating abnormal color lines.
- Single Horizontal Line An irregular Horizontal Line exists independently on the screen.
(Refer to Trouble Symptom Picture<6>)
- Block Horizontal Line Horizontal Line with Block Shape exists on the screen. (Refer to
Trouble Symptom Picture<5>)
- Single Vertical Line An irregular Vertical Line exists independently on the screen. (Refer to
Trouble Symptom Picture<4>)
- Block Vertical Line Vertical Line with Block Shape exist on the screen. (Refer to Trouble
Symptom Picture<5>)
<2> PCB Check Priority (Left to Right)
- Horizontal Line : SCAN, Y-SUS, DIGITAL
- Vertical Line : DATA, CONN-LEFT/RIGHT, DIGITAL
<3> Trouble Repairing Procedure
- Single Vertical Line Occurrence: DATA COF or PANEL has a trouble. So replace PANEL
- Block Vertical Line Occurrence: Most of the time this is caused by bad connection due to
extraneous materials or connectors not connected properly. Firstly, following Data Path,
DIGITAL CONN-LEFT/RIGHT ( Among seven DATA COF PAD, CONN-LEFT PCB
drives left 3(PC5~PC7), and CONN-RIGHT PCB drives right 4 DATA COFs. So, first check
which one of CONN-LEFT and CONN-RIGHT drive problematic COF PAD. ) DATA COF,
check the connection between each PCBs. Secondly, check if there are no dust, bits of iron, or
any other extraneous material between the connectors. Thirdly, reassemble and check if the
problem is solved. If the problem still exits, try to replace related PCBs one by one with the
DIGITAL PCB as a start.- Single Horizontal Line Occurrence : Firstly, if the position of the
line is at the upper part of the screen check SCANH PCB s connector