LG CM9750 - Booting in CD;Usb Function

3-10
ONE POINT REPAIR GUIDE
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.
8-2. CRYSTAL (X500)
8-2-1. Solution
Replace X500 on MAIN board.
8-2-2. How to troubleshoot (Countermeasure)
1) If 3.3 V & 1.2 V is normal, Check the CHIP_RESET of IC501 pin T12 on MAIN board.
 If CHIP_RESET isn’t high, Check MICOM(IC101) pin40.
2) If CHIP_RESET is high, Check the soldering status of 24 MHz crystal (X500).
3) If the crystal (X500) doesn’t oscillate, Check R508, R509, C502, C503 around crystal (X500).
 If there’s no defective component, then replace X500.
8-2-3. Service hint (Any picture / Remark)
XX
X
I
I
X
X
O
O
X500
< Signal waveform >
< MAIN board top view >
IC501
IC501
X500
X500