How to Fix Vertical Lines Screen Issue on Sony KLV-40EX430
This TV was brought to my workshop for repair, displaying vertical lines on the screen. After running for a while, the screen would go completely black. This issue is directly related to the display panel, and diagnosing it properly is crucial for an effective repair.
Fault Diagnosis
First, I checked the voltage of the DC-to-DC IC, which was normal. Then, I tested the voltage on the main IC of the scaler strip, labeled as IC2 on the chassis. The VCC supply, which was supposed to be 3.3V, was significantly lower. Upon further inspection, I found an inductor coil on this supply line, which was faulty.
- The TV had an issue with vertical lines and the screen going black.
- First, the DC-to-DC IC voltage was checked, and it was normal.
- The VCC supply (3.3V) of IC2 in the scaler strip was low.
- A faulty inductor coil was found on the supply line.
- The inductor coil was replaced, restoring IC2’s supply.
- As soon as the supply was restored, the panel display became perfect.
- The root cause was data processing failure due to insufficient voltage.
- Finally, the vertical lines issue was completely resolved.
Conclusion
In summary, the lack of proper voltage on IC2 in the scaler strip was preventing data processing, which resulted in vertical lines appearing on the screen.
