Pwm Modulation Check - LG DM5360K Service Manual

ELECTRICAL TROUBLESHOOTING GUIDE

4. PWM MODULATION CHECK

PWM MODULATION PART
YES
Check
CON103 pin8
(5.1 V).
YES
• Check IC404 pin6, 17, 34, 43, 52 (VDD 3.3 V).
• Check X402 (24.576 MHz).
YES
Check
X402(24.576 MHz)
operation.
YES
Check IC404 pin8 SCL input.
YES
Check IC404
pin7: RST, pin9: SDA
pin8: SCL output.
YES
Check
IC404 input data pin21
PWM wave.
YES
Check
PWM modulator output
FR: pin39(-), 40(+), FL: pin41(-), 42(+).
Other output
check.
YES
OK
NO
Refer to
SMPS troubleshooting.
NO
Check X402
(24.576 MHz).
OK
NO
Check line resistor output
RST: R425 / SCL: R426 /
SDA: R427.
OK
NO
Check MPEG PART
pin19, 20, 21.
NO
Check IC404.
OK
3-19
NO
YES
NO
YES
NO
YES
Replace X402.
Replace R425, R426, R427.
Replace IC404.