Pwm Modulation Check - LG CM4520 Service Manual

AUDIO ELECTRICAL TROUBLESHOOTIHG GUIDE

5. PWM MODULATION CHECK

PWM MODULATION PART CHECK
YES
Check
CN105 Pin11 3.7 VA.
YES
• Check IC601(PS9854) VDD 3.3 V
(Pin16, 25, 30, 33, 37, 42, 50, 64, 67)
• Check VDD Core 1.2 V (Pin1, 22, 45, 60,63)
• Check X602(19.2 MHz)
YES
Check
X602(19.2 MHz)
operation.
YES
Check
IC601(PS9854)
Pin54 CLK input.
YES
Check
IC102(LC87Fxx)
Pin41:PWM RESET
Pin45:PWM SDA
Pin46:PWM SCL
output.
YES
A
NO
Refer to
SMPS troubleshooting.
NO
Check X602
(19.2 MHz).
YES
OK
Check line
NO
resistor output
RST: R660 / SCL: R659 /
SDA: R658.
YES
OK
3-22
NO
Replace X602(19.2 MHz).
NO
Replace R660,R659,R658.