My Acer AT3220B LCD screen has a smokey streak near the center, it appears to be internal as the screen surface is clean . Can you help please ? Theo Vale

Most likely the internal power supply is defective.

Acer part # is- 55.M600B.001

its possible you arent using enough cleaner. use more and a slight damp paper towel to clean residue.

If it is a smeary screen, use a mild solution of washing up liquid and clean water on a clean cotton cloth.
That will remove any grease or finger marks without scratching the surface.

hi
just clean the 15 pin connector in the cpu end

If the pop up menu isn't coming on the the screen either, then it's a high possibly that the power supply board for the screen when bad. Most TV manufactures call it a Backlight Inverter Board. You can usually find a replacement over the internet.
Or, if you have some electronic experience, you can repair the board by soldering in the new part. The best thing to use to help with diagnoses is a Service Manual for the TV. Usually, costs under $20 over the internet if available. It will have schematics, test points, and part numbers for the TV.

Hi
You will need to visit acer website to see if their is an upgrade for the software some manufacturers do this some dont, it would be a matter of downloading and installing on flash memory card to insert in USB on tv,if not it will have to go into an approved acer service centre

check the inverter inside maybe loose or damage.

If the dark streak is static, then is liquid in lcd panel.

The TV reciever is capable of recieving an interference especially if your mobile cellphone is near the TV otherwise the black line which is shown on your screen is not normal,you have to sent your unit the service center.....