No Picture and Sound In LED TV Repaired
This Abans 24″ LED TV came in with the complaint of intermittent no sound and no pictures but the front power LED light was good. Usually when you see that the front LED light was blue in color, you will assume the power supply was good and the main suspect would be in the mainboard with a corrupted data in the memory ICs or other causes.
This means when you heard from the customer that told you the problem was no picture and no sound (with normal power light), we normally did not suspect the power supply fault.
Sometimes our guess could be wrong because the actual cause was indeed in the power supply section. If you look at the photo below you could see two electrolytic capacitor were bulged and these capacitors were located in the 12 volt and 5 volt DC output line.
By right if there is any abnormal DC voltage in the 5 volt line, the front LED color would have been always red and not blue but somehow in this case the power led light remained blue and this is why you and I will never suspect it was the power supply fault!
With the replacement of two new capacitors, the display and sound were immediately got back to normal.
You can see the blue screen and good picture in the below photos. Before that the display was totally dark and no sound.
So, what you have learned from this article? Don’t quick to judge or assume that the power supply is good. You need to test all the output dc voltages first in the power supply before you can conclude that it was good. After that, then only you hunt for bad components in the mainboard, T-con board and etc. All the best to you!
This article was prepared for you by Suranga Bandara who owns an Electronics repair shop in Anuradapura, Sri Lanka.
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