Chosen Solution
My samsung TV UN75F7100 presented a vertical black bars on the screen. I made a factory reset (service menu mute + 182 + power) and the bars disappeared, but the colors became saturated and dark. Sometimes when turning on the tv the bars come back, but not like before the reset. BEFORE RESET:
AFTER RESET:
The technical assistance condemned the panel, but if it was the screen, the bars would have disappeared after the reset ??? thank you all
@rogeracioly it is possible that the thought was that the cause for this are failed source drivers on the actual LCD panel. Since the reset somewhat worked and the lines disappeared I would consider this to be a bad video processor on the main board. Check the voltages etc. on the main board. Do check all the boards for burned components and check the capacitors on the power board for any leaking or domed appearance. Post some images of your boards with your question so that we can see what you see. Use this guide Adding images to an existing question for that
I agree with the first answer but would add that looking at the power supply is the most likely solution here. I would suspect that there are defective capacitors in the power supply that are letting AC ripple get to the data lines. If the voltage is sufficiently low and there is excessive ripple, the logic ICs will get “confused” and odd behavior will result. Please note that upon warming up, these parts can start to work normally which would explain why the reset works. Take a look for the “bulged” capacitors and update this with the results. Dan
