12 volt tv?

[cvin]

i have what looks like a 12 volt tv, my trailer repair guy said it was

but no power/red light on the front except for the few min i had the genny running earlier

genny issues so cannot test more that way

fuse is fine, i am not sure what else to check

it is an insignia and i think it was the one that came with the camper

am i wrong in thinking this is supposed to run off my batteries? would there be a switch on the back to turn it to 12 volt or something

thanks for any help