Booting In Cd/Usb Function - LG OK99 Service Manual

4. NO BOOTING IN CD/USB FUNCTION
After you turn on power key and displayed message in the following order (HELLO  VOL XX  CD
or USB) on VFD, it will not display other message on VFD, and it will not boot-up normally.
4-1. NO DVCC_3.3V, 1.2 VA
4-1-1. Solution
Please check and replace IC202, IC204, IC205 on MAIN board.
4-1-2. How to troubleshoot (Countermeasure)
1) Check voltage of IC202 AND IC205 pin4 on MAIN board.
 If IC202, IC205 pin4(about 5.1 V) Input 5.1 VA doesn't come out, check 5.1 VA from SMPS board.
2) If IC202, IC205 pin4(about 5.1 V) is normal, check the PWR_CTRL(IC204 pin5) is high (about 3.3 V).
 If PWR_CTRL isn't high, check pin D11 of IC501 & R5B78, R214, R233.
3) If PWR_CTRL is high, check R5B78 and if there's no defective component then check IC204 pin1 short
with GND.
4) If 3.3 V(DVCC_3.3V) is normal, check 1.2 VA output(C221, C226, C287, C288, C229) voltage of IC205.
 If 1.2 VA of IC205 doesn't come out, then replace IC205.
4-1-3. Service hint (Any picture / Remark)
IC202 IC202
< MAIN board top view >
ONE POINT REPAIR GUIDE
IC204 IC204
< MAIN board bottom view >
3-6
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IC205 IC205
Only for training and service purposes.