**LG TV, raster shows a horizontal bright line, but the audio is normal.**
**Analysis and Repair:** Preliminary diagnosis indicates an issue with the vertical output circuit. Measuring IC401 (LA7838), pin 12 (vertical deflection power output) voltage reads 12.5V (normal), indicating that IC401 is functioning properly. Checking the voltages on all pins of IC401, it was found that the voltage on pin 6 (5.6V) was significantly abnormal. Focusing on components around pin 6, it was determined that the external sawtooth wave forming capacitor C418 (1uF/35V) had lost its capacitance.
**Solution:** Replacing C418 with one of the same specifications resolved the fault.
**Repair Tip:** After C418 was damaged, no vertical sawtooth wave was generated, and there was no vertical scanning voltage output. Since the vertical sawtooth wave voltage is also sent to the pincushion correction circuit, this resulted in pincushion distortion, causing the raster to appear as a single horizontal bright line.
**Source of Article:** Beijing LG TV Repair Center http://blog.tianya.cn/blogger/blog_main.asp?BlogID=3701288.