Daewoo DT-4220NH Service Manual page 42

Main PCB Trouble Diagnosis
(4) With Component inputs
Check TP136(V sync), TP135(H sync)
If signals do not appear, replace MAIN PCB.
3. When DTV (1080i, 720P, 480P) signal do not appear on screen
(1) Input PC or VIDEO signal and see if PC or VIDEO images are displaying.
If "no signal", check TP188, 187 and 184.
If DCLKB, DHS and DVS signal do not appear, replace MAIN PCB.
(2) Check TP136(V sync), TP135(H sync) <when 1080i >
If above signals do not appear, replace MAIN PCB.
4. When PC signal do not appear on screen
(1) Input DTV or VIDEO signal and see if DTV or VIDEO images are displaying.
If "No signal", check TP188, 184 and 187.
If TP188, 184 and 187 signal do not appear, replace MAIN PCB.
(2) Check TP124 (V SYNC), TP125 (H SYNC) (when 800 X 600).
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