White Screen Problem in Main Board of Sony KLV-46EX520
How to Fix White Screen Problem on Sony KLV-46EX520 Learn how to diagnose and repair the white screen fault of this Sony model. When this LED TV came to me, I switched it on and checked it. The sound was absolutely accurate. The screen was predominantly white. At first glance, my impression was that there was a problem with its panel, but unexpectedly, this did not happen. You will find out what the real fault was later in the article.
Main Board and Screen Inspection – Sony KLV-46EX520
I opened this LED TV in the workshop lab for repair, and first of all, I did a visual inspection of it, especially the board. It is a little old model, and old models have corrosion issues in the main board, so I pay special attention to this aspect, but in this case the main board was in good condition. Now the next step was to test the screen with another main board by connecting a separate LVDS signal. This process will let me know whether the white screen fault is in the main board or in the screen.
Main Board Fault Diagnosis
I bypassed the power supply and backlight section of this set and tested the screen with a separate main board. The screen was working perfectly, and the display was coming with excellent results. Now my full attention will be on the main board because it has been proven that the white screen fault lies in it. As a precaution, I tested all the supplies of the main board for voltage. All of this in the correct amount. Now the work to be done is a bit more meticulous, as we will check the resistance of this main board.
Final Diagnosis and Fault Repair Explanation
To diagnose this fault, I checked the resistance of the main board, including the array resistor connecting the system to RAM and the system to eMMC. All these resistors were giving me the correct value. In this model, a crystal is used on one corner of the system IC. I checked the connection of this crystal with the system IC, which was correct, but the fault was also there. I will explain it openly. One pin of the crystal connects directly to the IC, and the other pin has 820 ohms in series, but a 1-megohm resistor is also in parallel. This resistor had increased its value. I changed it, so my fault was fixed.
Quick Recap of Fault Diagnosis Steps
- The Sony KLV-46EX520 TV had a white screen fault while the sound was normal.
- The screen and backlight were tested separately and found to be working perfectly.
- The main board became the main focus of inspection.
- Array resistors between the System and RAM, and between System and eMMC, were tested — all showed correct values.
- The crystal oscillator near the System IC was checked for continuity and connection.
- One crystal pin was directly connected to the IC, and the other through an 820Ω resistor in series.
- A 1MΩ resistor was connected in parallel with the crystal circuit.
- The 1MΩ resistor had increased in value, which caused the white screen display problem.
- After replacing the faulty 1MΩ resistor, the TV display returned to normal and the fault was fixed successfully.
Conclusion
How to Fix White Screen Problem on Sony KLV-46EX520 You saw how we diagnosed this fault step by step. We tested its screen separately by installing another main board so that we could be sure in which area the fault was. From this test, we came to know that the white screen fault was in our main board. In the main board, along with the main system IC, we found a 1 megaohm value increase in the crystal circuit, which fixed our fault by replacing it. So the lesson we get from this article is that even the smallest part can create a very big fault.
FAQ
Q1:Why is my Sony TV screen white?
There is a screen problem. This fault can also occur in the T-con board. There is a very small chance that the main board is faulty.
Q2:How to fix Sony display problem?
This is a general question. It depends on what kind of fault is appearing in the image on the screen. If there are lines, then they are related to the COF (chip on film).
Click below to view or download the full-size image of this fault
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Shaukat Ali has over 30 years of experience in LED TV repair, specializing in chip-level repair work. He is an expert in Sony LED TVs, and also repairs other major brands like Samsung, TCL, Orient, and Haier. His expertise includes display panel faults, motherboard issues, power supply circuits, T-Con, and HDMI faults. Based in Lahore, he shares real-time fault finding cases from daily repair work to help technicians and learners with practical experience.
📞 Contact: +92 321 4066054