LG BP340 Service Manual page 19

NO BOOTING WHEN YOU TURN THE UNIT ON
When you plug power cord and turn the unit on, LED light won't turn green, the unit won't output
video and read disc normally.
1-3. Please check main board IC U2 & U3 signal and its peripheral circuit.
1) Please check if DDR_VREF 0.75 V from main board U2 & U3 is normal.
If DDR_VREF 0.75 V is not normal, please check if U2 & U3 and its peripheral circuit are failure.
1-4. Please check main board IC U11 signal and its peripheral circuit.
1) Please check if VCC_BD_LD 8.2 V from main board Q9 S polarity is normal.
If VCC_BD_LD 8.2 V is not normal, please check if U11 and its peripheral circuit are failure.
U11
ONE POINT REPAIR GUIDE
< Main board top view >
U3
3-4
U2