LG OK99 Service Manual page 32

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.
4-2. CRYSTAL (X500)
4-2-1. Solution
Replace X500 on MAIN board.
4-2-2. How to troubleshoot (Countermeasure)
1) If 3.3 V & 1.2 V is normal, check reset 'High' of IC501 pin T12 on MAIN board.
  If CHIP_RESET isn't high, check the IC505.
2) If CHIP_RESET is high, check the soldering status of 24 MHz crystal (X500).
3) If the crystal(X500) doesn't oscillate, check R5B4, R5B6, C5B2, C5B5 around crystal(X500).
  If there's no defective component, then replace X500.
4-2-3. Service hint (Any picture / Remark)
X X X I I
X X O O
< Signal waveform >
ONE POINT REPAIR GUIDE
X500
X500 X500
< MAIN board top view >
3-7
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IC501 IC501
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