Trouble Shooting; Checking For No Picture - Daewoo DP-42SM Service Manual

4-1. Checking for no Picture

A screen doesn't not display at all and condition of black pattern or power off.
(1) Check whether the CTRL B/D LED(D1~D4) is turned on or not.
(2) Check the power and signal cable of CTRL B/D.
(3) X B/D, Y B/D, Z B/D is well plugged in.
(4) Check the connection of X B/D, Y B/D and Z B/D to CTRL B/D.
(5) Measure the output wave of X, Y, Z B/D with oscilloscope (more than 200MHz) and find the
trouble of B/D by comparing the output wave with below figure.
- Measure Point fo Y B/D : TP (Connector P4 80 pin)
- Measure Point fo Z B/D : Connection part of panel (SUS_OUT)
- Measure Point fo X B/D : L1(RIGHT), L2(LEFT BOTTOM)
(6) Check the SCAN(Y side) IC
(7) Check the DATA(X side) COF IC
(8) Replace the CTRL B/D.

4. Trouble Shooting

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