LG TH900 Manual page 6

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 VA & 1.2 VA is normal, check reset 'High' of IC501 pin T12 on MAIN board.
  If MAIN_RESET isn't high, check MICOM (IC101) pin40.
2) If MAIN_RESET is high, check the soldering status of 24 MHz crystal (X500).
3) If the crystal (X500) doesn't oscillate, check R508, C502, C503 around crystal (X500).
  If there's no defective component, then replace X500.
4-2-3. Service hint (Any picture/ Remark)
< MAIN board top view >
ONE POINT REPAIR GUIDE
IC501 IC501
X500 X500
X X I
XO
< Signal waveform >
3-7
X500