LG STUDIOWORKS 77M Service Manual page 11

NO V-DEFLECTION
(ONE HORIZONTAL LINE)
CHECK
IC601 PIN 3
(15V)?
YES
CHECK
IC601 PIN 7
(40V)?
YES
CHECK
IC701 PIN 12, 13?
3V
YES
TROUBLE IN
IC601, V-CIRCUIT
6. NO VERTICAL DEFLECTION
NO
NO
NO
TROUBLE IN
R603, Q601~Q603,
15V LINE
TROUBLE IN
HIGH-VOLTAGE OUT
CIRCUIT, D713
TROUBLE IN
IC701