Daewoo DT-4220NH Service Manual page 41

Main PCB Trouble Diagnosis
When Y Cb Cr input : TP261 located in the center of the PCB near IC121.
COMPOSITE Input : Check Positive polarity of CE203 located near IC132.
S- VHS input : Check Negative polarity of CE284 located near IC159.
If above signals do not appear, MAIN PCB needs to be replaced.
(3) With Video or S-Video inputs
Check TP138(V sync), TP139(H sync)
If signals do not appear, replace MAIN PCB.
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