LG LAS950M - Page 35

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ELECTRICAL TROUBLESHOOTING GUIDE
NO 6.2 VA
NO VCC_5V (USB & LCD)
Is 25 VA to pin7
of IC304 normal?
Is 6.2 VA to pin2
of IC301 normal?
Check 25 VA on SMPS board.
Check IC304 & 6.2 VA power line.
YES
YES
YES
YES
YES
YES
NO
NO
Is D300 normal?
Is there H (3.3 V) voltage
to pin1 of IC301?
Is switching pulse of
IC304 pin1 normal?
Is there DC voltage
to pin3 of IC301?
Replace D300.
Check R314.
Replace IC304.
Replace R317, R320, R355 & IC301.
NO
NO
NO
NO
6.2 VA power line is normal.
VCC_5V power line is normal.
YES
YES