Pwm Modulation Check - LG RAT376B Service Manual

AUDIO ELECTRICAL TROUBLESHOOTIHG GUIDE

5. PWM MODULATION CHECK

PWM MODULATION PART CHECK
YES
Check
CN105 Pin10 3.7 VA.
YES
• Check IC602(PS9850) VDD 3.3 V
(Pin16,24,29,32,35,40,48,61,64)
• Check VDD Core 1.2 V (Pin1,21,43,57,59,60)
• Check X602(19.2 MHz)
YES
Check
X602(19.2 MHz)
operation.
YES
Check
IC602(PS9850)
Pin51 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: R636 / SCL: R637 /
SDA: R638.
YES
OK
3-22
NO
Replace X602(19.2 MHz).
NO
Replace R636,R637,R638.