Samsung cea455 series Service Manual page 21

ATT 4. ABNORMAL MODE CHANGING(MODE DETECTING)
Check Mode Changing
J
I
MODE1 (CGA:15.75kHz) MODE2(EGA:22kHz)
I
Is the Vertical input signal
NO Is the V input signal
positive? negative?
YES Check PC and Signal Cable YES
connection
Is the control voltage Ov? NO Is the control voltage 3.2V?
(pin 8 of IC102) Is the H-SYNC Positive?
Is the H-SYNC positive? Is the V-SYNC negative?
(pin 6 of IC102) Is the MO negative?
Is the V-SYNC positive?
(pin 11 of IC102)
Is the MO positive?
(pin 8 of IC101)
YES Check IC102,IC101 and YES
its related circuit
NO
Is the 9,10,11 of 1C402 12V? Is the 9,10,11 of 1C402 OV?
I
YES Check Q606,pin 7 of 1C402(-5V)? YES
NO
Is the FBT B+ 54V?
I
Is the FBT B
+
65V?
YES Check Q603,Q604,Q402,T403(FBT)?
YES
NO
Does the relay(RL401) Does the relay(RL401) open?
I
operate(OV)?
Check Q403,Q404,RL401 and
its related circuit
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