LG CM9530 - ELECTRICAL TROUBLESHOOTING GUIDE

3-6
ONE POINT REPAIR GUIDE
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 VCC33, VCC12
4-1-1. Solution
Please check and replace IC505, IC509 on MAIN board.
4-1-2. How to troubleshoot (Countermeasure)
1) Check Voltage of IC505 pin2 on MAIN board.
 If IC505 pin3 (about 4.9 V) & D500 Input 5.6 VA doesn’t come out, check 5.6 VA from SMPS board.
2) If IC505 pin3 (about 4.9 V) is normal, check the PWR_CTRL (IC505 pin12) is high (about 3.3 V).
 If PWR_CTRL isn’t high, check pin63 of IC101 & R179, R59E.
3) If PWR_CTRL is high, check R59D, R59B, R59C and if there’s no defective component then replace IC505.
4) If 3.3 V (VCC33) is normal, check output (pin2, 4) voltage of IC509.
 If 1.2 V of IC509 pin2, 4 doesn’t come out, then replace IC509.
4-1-3. Service hint (Any picture / Remark)
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