No Display With Burnt Smell and Noise From a 21″ CRT TV Fixed
Customer sent to me a 21″ Philips CRT TV with the complaint of no display but have power. Once I turned the set On I could smell something burning inside and with noise also. I suspected it was arcing from the flyback.
When the TV cover was removed, the first thing I do was to look at the flyback area and true enough there was a dark burning mark on it. Please see the photo below:
I did not check whether the Horizontal output transistor was good or not because if you can hear arcing sound means the flyback transformer was energizing. The part number was 19857 and I had the stock.
Replacement was done and I powered On the set and found that there was another problem.
There was sound and OSD menu but no display (raster/noise). Look at the photo below:
But when I connected signal to AV input, it was working fine!
After I had confirmed the AV section working good, I guess there must be some other faults in the flyback circuitry nearby. I believe the arc could have killed some components. With visual inspection again, I saw a burnt resistor located beside the flyback. This is the reason why no display but AV have display.
Since I do not know what was the part number, I searched for the schematic diagram and eventually found it and the value was 12 K ohm.
After the replacement was done, the display appeared normal again. See the two photos below:
Conclusion- In the future if you come across problem where there was arcing in the flyback transformer, if possible check also the surrounding area for bad or burnt part. Hope to see you again in the next repair articles!
This article was prepared for you by Suranga Bandara who owns an Electronics repair shop in Anuradapura, Sri Lanka.
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