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[ Flow chart 2 ] Symptom: power not on
Trouble description: test after machine power on, standby indicator light is not on and +12V power
outputted by power board is abnormal.
Y
Y
Y
Y
N
Power not on
Check
whether power
board flat cable
has 12V voltage
Check
whether 12v
resistor to ground
is normal
Check whether filtering
capacitor TC3/TC4 has
electric leakage and
short-circuit
Check
whether power
board TC1 has 310v
voltage
Check fuse, TC1 and
rectifying bridge
Check
whether each pin
voltage of U1 is
normal
N
Check according to
troubleshooting process
for“player not switch on”
Check
whether Q1 is
damaged
Y
Check
whether VD4
has secondary
voltage
Y
Check
whether VD4
secondary voltage is
normal
Y
Check
whether voltage
of TC2 two ends
is normal
Y
N
N
N
Check NCP1207 and
peripheral elements
Change Q1
Check feedback loop
U2/U3
Change L3
END
N
Y
N
N
Check
whether transformer
is normal
Change transformer
N
Check VD4