How to fix 5 blink error Sony Klv40bx450
A Sony LED TV in my workshop Klv40bx450 This set came in for repair. The fault in this set was five blinks.
Fault finding
I opened the set and opened its panel and checked the voltage of its panel DC to DC circuit. Its AVDD voltage used to drop as soon as it was turned on. I checked for short circuit on its AVDD track but here There was no short circuit here, the main IC in this set SM4109 This IC has been used in a DC-to-DC circuit. I checked the VCC of this IC at three points, three volts, and the voltage was getting low. I was getting a reading of two points, four volts.
Fault confirmation
When I attached an external power supply to these three-point three-volts, my set started working perfectly.
Fault Diagnose
Now I had to trace its original fault.
I have his IC. SM4109 The relevant parts of the test found a fault in the three-point three feedback circuit of this IC, where three voltage divider resistors were installed. Rd3 5.5k R14 380k R26 1.8k This voltage divider was supplying the reference IC from the output of the three-point three, and this feedback was the cause of the error.
The fault has been cleared.
I changed the resistors in RD3 5.5k and my set started working perfectly.
Fault image
I have also attached a photo showing the fault area and faulty part clearly so that it is easy for the technician to understand.
Conclusion
While doing chip level repairs, we should examine even the smallest thing well, especially in Sony, and try to do the job well. Good and perfect fault finding is the hallmark of a good technician.
sony-klv-40W652D-sound-is-muted
