I received this television from my neighbor and the complaint was sound is okay but no picture symptoms.
First I had to confirm if what the client is saying is correct and after switching on the television indeed the symptoms were confirmed right.
I took the set to my workshop and before embarking on opening the set I decided to use a bright light from the torch to see if there is something on the screen like dark picture which will guide me exactly which circuit to suspect even before opening the set.
After using a strong light from the torch this is what I saw...
Yes! Indeed there is an image/picture but it is too dark to see...as I have written in my latest book on lcd led repair, LCD-LED television do not generate their own light like CRT television and therefore need something to light up from the back so that the image can be visible- This is what we call back-light.
So if there is a problem with the back-light circuit then images will be dark and with that I decided to open up the set to do further investigations with my main interest on the back-light circuit which of course include Led driver circuit.
After opening the set before pulling the meter it is very important to observe the circuit using your naked eyes looking for an suspicious components or area and after circling the board with my eyes I picked a capacitor with the top slightly swollen as you can see here below.
Upon more scanning of the capacitor I noted it is actually located on the led back-light driver circuit and yes! This could be the culprit.
I pulled a capacitor 220uF/50V from the capacitor kit and replaced the swollen capacitor without further testing since testing a swollen capacitor is a waste of time.
After replacing the capacitor I now had to test the effect of that one component and after applying the power the television came up smiling with the picture and sound very clear.
Thank you friends
See you in the next class