Sony XR-55X90K Service Manual page 18

TROUBLESHOOTING
1.2 No Power u-com Failure
3.3V_STBY
Power-Board
or
Local Dimming-Board
12.7V_MAIN
R450
12.7V_21V_AUDIO
R444
3.3V_STBY
GND
Main Board
VDD
#pin6
#pin9
BL_ON
#pin12
#pin7
POWER_ON
#pin10
12V_MON
#pin16
ADC port
#pin13
GND
TYPE_DET
#pin17
#pin18
DC_MON
#pin11
ADC port
#pin14
#pin3
#pin8
GND
P-on u-com control signal path summary
PGOOD_1
DDCs:
P_ON_#1
0.9V_BE_DDC_1 (IC4802), 0.9V_BE_DDC_2 (IC4803), 0.8V_BE
(IC4809), 0.7V_BE (IC4810)
LDO :
1.8V_EMMC (IC2201)
DDCs:
5V_MAIN&5.0V_VBUS&5V_AUDIO (IC600),
1.0V_TU_P(IC603), 1.8V_M5 (IC813), 1.0V_M5 (IC812),
P_ON_#2
0.8V_M5_CPU (IC810), 0.8V_M5_GPU (IC811), 1.8V_BE_DDC
(IC4800)
LDOs:
3.3V_MAIN_H (IC403)
FET SW :
3.3V_TU_P (Q602), 3.3V_MAIN &3.3V_AUDIO(Q611),
P_ON_HL
OPWRSB
#pin2
ORESETB
DC_OFF_DET
X_BL_MUTE
DDC : 0.8V_M5_CORE (IC804)
FET SW : 12.7V_LNB (Q604)
SW IC : 3.3V_TU_P (Q609)
USB VBUS SW (IC3803/IC3804)
SOC Muffin 5 (IC1000)
18
SYS SET