LG S94T1-S Service Manual page 48

When you turn on your set, it will blank / no message on front panel, and it will not boot-up.
2-5. IC155 (No 3.3 V)
2-5-1. Solution
Replace IC155 on MAIN board.
2-5-2. How to troubleshoot (Countermeasure)
1) Please check 3.3 V of IC155 on MAIN board.
2) If 3.3 V voltage doesn't come out,
- Check IC155 pin3 (VCC 3.8 VA).
If there is no 3.8 VA, please check 3.8 VA from SMPS.
3) If VCC input IC155 there are 3.8 VA signal,
First of all, check the pin6 is high and if it's high, check resister value
and if there's no defective component please replace IC155.
4) After changing it, if the set is still not booting:
- Check 1.2 V / 1.5 V is normal. (please refer to other sections of this guide)
- Check crystal X501 refer to item 2-6.
- Check eMMC flash IC (IC506) refer to item 2-7.
- Check DDR IC (IC503, IC504, IC505) refer to item 2-8.
- Check MT8580 IC (IC501) refer to item 2-9.
2-5-3. Service hint (Any picture / Remark)
ONE POINT REPAIR GUIDE
< MAIN board top view >
2-33
IC155