Samsung SCM-7270 Service Manual page 18

Troubleshooting
6-1-2 No Output
Voltages at
IIC1(LC1851N) and semi
conductors tuner section
are normal
TCON1 is at
1.5V±1.5 on low coverage
7.5V±0.5 on high
coverage
Voltage at FET
are normal
6-1-3 AM No Sound
at LC1851N(IIC1) and tuner
semi conductors are normal
(Refer to Schematic Diagram)
Voltage between
TCON1: AM(MW)
Low coverage 0.9V
High coverage
LW Low coverage 0.7 V
High coverage
Check loop antenna soldering and
connection of OL1, OL2, OT1,OT2, IT2
6-2
Yes
Yes
Voltage
Yes
±0.5
± 0.5
9V
±0.5
± 0.5
4.5V
Yes
No
Voltage at power supply
section
Check pump charge circuitry(OQ5)
No
connection or soldering of SCON1,
FCW2, FCON1 soldering of pin77
of LC72362
No
No
Check voltage at power
supply section
Check pump charge circuitry
No
(OQ5) connection of SCON1,
FCW2, FCON1 soldering of pin77
of LC72362N
Replace FET
Samsung Electronics