how to fix sony klv-40R472B dead tv
Sony klv-40r472b dead fault professional repair guide
Sony LED TV model number KLV-40R472B came to me for repair. This set was completely off condition and its standby light was not even turning on. The customer said that this set I turned it off at night and it didn’t turn on in the morning. I told the customer that I needed time to fix it.He said, “Okay, you fix it peacefully.” My customers are like this, I’m very happy. Anyway, let’s get to work.
Fault Analysis
I opened the set in the lab to work. Since this set is a model with a separate power supply, it comes with a 19-volt adapter.I checked the 19 volts of its adapter with a multimeter and they were perfect.This main board has an eight-pin MOSFET installed to pass 19 volts. This MOSFET was supplying out, meaning it was fine. Now I checked its 3.3 volts and there is no problem here either.3.3V Were becoming perfect.1.2V And 1.5 voltage were not present 3.3 volte On the track A MOSFET was installed for standby, I shorted its source and drain.Then i Check 1.2 volte and 1.5 volte regulator supply 1.2 voltage supply I saw a lot of increase here.1.8 volte
Fault tracing
I checked the feedback resistance of this 1.2 volt regulator by disconnecting it from the circuit and found that the value of one of the resistors was 4.7 kΩ.It had increased its value, now its value 5.8k When I changed the resistor, all the voltages on the board were accurate, but the set still wouldn’t turn on.Now I started checking the communication between its NAND flash and system IC. Here I am 47 Ω Array resistors Find one of the D-values.I changed this and my set started working perfectly.
Fault image
A fault photo has been attached to the article, which clearly shows the fault area and faulty part of the main board, so that it is easier for fellow technicians to understand the fault.
Conclusion
This set had a fault in two places. Such faults need to be solved with great effort and attention. Sometimes it happens that two or more faults occur in the same set, but a true technician can fix them.
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thank you:
Shuakat Ali
