Samsung CT721APX/XAX, Service Manual, Page: 18 / 53

Troubleshooting
Samsung Electronics 5-3
5-3 No Power (No Raster, No Sound)
Normal
Check
the voltage of
IC801 Pin 1(140V)
Check the
voltages of IC801
(140~150V)
Check D806
Abnormal
Check the voltage of
IC801 Pin 3, 4,5
(15 ~ 20V)
Check IC802 and Q806
Check/Replace
IC801 and Q806
Abnormal
Normal
Abnormal Normal
Check
secondary power line voltage
(6.8V, 14.5V, 30V, 9V)
Check the secondary
terminal short/open
of trans
Abnormal
Abnormal
Normal
Check the voltage
of IC901 pin 39, 22
(normal : 5V)
Check the Reset of
pin 35 and the Hold "H"
of pin 49
Check/Replace
IC901
Check
IC901 Pin 1 (Low
when power On)
Check/Replace
the Power Q806
Check/Replace
Q806
Check the voltage of
TB01 Coil Pin 20
Check the voltage
of tuner
Normal
Normal
Abnormal
Abnormal
Normal
Abnormal
Normal
(When ST-BY)
3 : 20V
4 : 1.2V
5 : 6.5V