Samsung UE55F70 Series - 4-2. Fault Symptom Diagnosis

4-2. How to Check Fault Symptom
4-2-1. NO Power and No Video
Power indicator LED is on?
No
Check the power cord connection.
Yes
Check ‘Stand-By A5V’ 5V appear at
BD204?
0V to 5V (CN201 #4) -
No
Cause : There did not supply the
power from SMPS.
Measure : Change 24P power cable
and SMPS.
Yes
Set On
Yes
Check ‘SW_POWER_TO_SMPS’ more
than 3.3V appear at CN201(#2)?
0V to 3.3V↑ (CN201 #2) -
No
Cause : Main IC(NT13) did not control
the SW_Power.
Measure : Change the Main Assy.
Yes
Check ‘Power input of Main Ass’y’ ?
DC B13V, B5.3V appear at CN201 #3, 11,
13, 21, 23 (B13V) CN201 #1, 3 (B5V)?
0V to 13V (CN201 #3,11,13,21,23) -
0 to 5V (CN201 #1, 3) -
No
Cause : There did not supply the
power from SMPS.
Measure : Change 24P power cable
and SMPS.
Yes
Check ‘Power of main IC (B1.0V/B1.1V/
B3.3V)’ Check ‘Power of DDR IC(B1.5V)’
appear at BD224(1.0V), BD234(1.1V),
BD239_LD, BD225, BD226, BD227,
BD242(3.3V) BD228, BD222(1.5V)
No
Cause : There is problem at DCDC
(IC202, IC213, IC204, IC201)/
LDO
Measure : Change the Main Assy.
Yes
Check ‘Power of LVDS (13V)’ appear at
TP-PANEL_VCC?
0V to 13V (IC1201 #7, 8) -
No
Cause : There is probem panel or
T-con board or Main assy.
Measure : Change the Main Assy.
Yes
Change the LVDS cable ?
No
Change the Panel.
4-4
4. Troubleshooting