Both can be used in most situations. "What's up" is considered informal and would mostly be used with people you know well or have built a solid rapport with. If you have any other questions you can always send me a message. Best of luck Ali!

whats up with the TV is more colloquial but I definitely understand what you mean. I would probably say whats wrong with the TV if the TV isn't working.

In colloquial, spoken English, they are both correct, but in formal English only 'What's wrong' is correct. 'What's up' is very informal.

Young people especially use the term 'whats up?' to mean 'what's going on?', 'what's happening?' These terms can be literal or they can simply be a greeting to be used in place of 'Hi.'