[yekwart]

Thanks for the help.

The batteries were not new. I checked them with a multimeter and they are all reading roughly 1.3v. Unfortunately, I don't have 4 new ones. I did replace them with some other ones that showed 1.41v when tested and when I swithced the TV on it lasted for 4 minutes before going black. When switched back on it lasted 20 seconds before going black.

I haven't tested using an AC adapter yet, but when I find a matching one I will.

Edit: Just noticed in the manual it says "As the batteries become weak, the sound becomes distored and the picture becomes dim. When the picture becomes dim, replace all the batterries with new ones."

The sound didn't sound distored to me and the screen going frrom working to black, was pretty instant.

Edit2: Troubleshooting section in manual says "No Picture but good sound - Batteries are weak"

So still very possible