Trouble In H.v Sync - NEC MultiSync V720 Service Manual

6. TROUBLE IN H. V SYNC
PROBLEM IN
HOR. OR VER. SYNC
YES
CHECK
CONNECTOR S702
(PIN3,4), SIGNAL
YES
CHECK
U701(PIN 40,39)
H/V SYNC.
SIGNAL
YES
CHECK
U701(PIN 32,33)
H/V SYNC.
SIGNAL
YES
CHECK
U301(PIN 3)
U402(PIN 4)
YES
PROBLEM IN
U301, U402
NO
NO
CHECK
U701(PIN 5)
NO
VOLTAGE
5V?
YES
CHECK
U701(PIN 8)
NO
FREQ.4MHz
YES
PROBLEM IN
U701
37
PROBLEM IN
SIGNAL CABLE
PROBLEM IN
H/V SYNC LINE &
Q301, Q401
NO
NO
PROBLEM IN
5V LINE
PROBLEM IN U203
12V, 77V VOLTAGE