How to Fix Dead LED TV Sony KLV-48R352B (No Power Issue)
Sony LED TV model number KLV-48R352b came to my workshop for repair. This TV was completely dead; not even its red light was showing. This is a common fault. My first assessment of this model was that its system IC was not working. The customer said that the TV was working. We were watching a program, and suddenly the TV turned off. I asked the customer for time and said, “I will diagnose the fault and tell you.” He said, “Okay, in this article, we will explain how to fix a dead Sony KLV-48R352B LED TV (no power issue).” We will explain this fault step by step so that it is understandable for both technicians and ordinary users.
Physical Inspection
I opened this set in the workshop lab and started the physical instruction. I looked at things visually to see if there was any damage, then I checked things by hand to see if anything was hot. The benefit of this inspection is that sometimes you see a damaged part, you feel something moving, which brings you very close to the fault. For example, you may find a swollen capacitor, you may see a burned resistor, or you may see a component failing due to overheating. The first step should be to do a physical inspection. In this case, I did everything right; I didn’t notice anything unusual.
Fault finding
Fault-Finding Process for Sony LED TV KLV-48R352B Let’s start. I first checked its mainboard voltage. First of all, I checked its mains voltage, and it was there. Now I am writing down all the voltages below so that the concept becomes clear.
- 19 voltage were present.
- 3.3 voltage Were present.
- 1.5 voltage Were present.
- 1.2 voltage Were present.
The way to check the voltage as soon as you turn on the set is that 19 volts should definitely come on. Because five volts will be generated from these 19 voltages in the circuit, the responsibility of these five volts will be to generate 3.3 volts. Now, it is normal for 3.3 volts to be present. It has a standby FET that is responsible for passing 3.3 volts in when the circuit allows it. This is what causes the 3.3 volts to be 1.5 volts. Well, it was a matter of sequence, which voltages are generated from which in the circuit. What I mean by that is that all its voltages were being generated at the same time, and this is a defect.
Fault diagnose
I have checked all the regulators of this set thoroughly to see if they are working properly or not, and after that I connected the system to the ground flash. I have also checked the resistances of them thoroughly. All the resistors were fine and in good condition. I checked them in depth. I checked all the voltages going to the system IC thoroughly. But the system IC seemed to be completely dead. After that, I checked the frequency on the system crystal. I couldn’t find the correct frequency there, so I decided to change its crystal. I had a crystal of the same value. I removed it from a board and inserted it into it, and then my set started working perfectly; my TV turned on.
Crystal Replacement in Sony KLV-48R352B
I didn’t have a new crystal, but I took it out of a board and changed the crystal, and my set was fixed. Crystal failure is not common. There are very few cases where the crystal of a system IC is faulty. This was a new experience for me as well. However, we replaced it, and our set was fixed. There is another thing to consider here: two ceramic PFs are also installed along with the crystal, so sometimes these ceramic capacitors get damaged, due to which the system frequency is upset and the system does not work. A technician should also keep in mind that it is not necessary that the crystal itself be damaged. These ceramic capacitors can also be damaged. They should also be checked. But in my case, the crystal itself was damaged, so I replaced it.
Conclusion
As we saw, all the voltages of this set were coming at the same time, and the voltage measurement was fine. There was no problem in it. The system was not resetting. The main reason for this was oscillation and oscillation. And the reason for this isolation problem was the crystal, which we replaced, and our set was fixed. The point is that a technician should check everything while working and adjust it according to his understanding. The technician usually pays very little attention to the parts that are rarely damaged, but as I said, everything should be checked very carefully while taking the series.
FAQs (Frequently Asked Questions)
- In Sony models like this, the dead fault is usually caused by a voltage drop. It occurs because a supply has decreased or stopped.
- Or another reason could be that the problem arises due to system-to-NAND flash communication. There are resistors installed between the system and NAND flash, which usually get damaged. This is a common fault.
Click here to read the detailed article on the 6 blink error issue in Sony KLV-40R352B LED TV.
Shaukat Ali
Shaukat Ali is a professional Sony LED TV repair technician with over 30 years of experience. He specializes in diagnosing and fixing complex display and board-level faults. Based in Lahore, he shares real-world repair cases to help both customers and fellow technicians.