Probably a bad breaker, but the symptoms are also consistent with a mild overload causing the breaker to heat up and trip over time, the longer you let the breaker cool before resetting, the longer it takes for it to heat up and trip again.
I'd leave it turned off until you've ruled out a short in the wiring or other overload condition causing it to trip - if it's a short somewhere, that short is causing a lot of heat somewhere in the walls or other inaccessible place.
It's possible that the wiring is not straightforward and there's a load connected to the breaker that you're not aware of - like maybe the toaster in the kitchen is on the same circuit so be aware of what other appliances in the house may be in use when you experience the trip.
The hard thing about finding a short circuit is that if it's due to, say, a bad connection in a junction box under the floor, it may not short out until you walk near it and make the wires flex enough to touch. If you notice any kind of burning smell associated with the trip, keep the breaker turned off until someone finds the problem.
Some types of breakers are subject to "nuisance tripping" even without any overload or wiring problems - if you have an AFCI or GFCI breaker, you could be experiencing nuisance trips due to a device that's plugged in.
If you have 20A service to your bedroom, you're probably in a newer house (15A is more typical, especially in older construction), so a short is less likely than if you're in an older house so the most likely cause of the problem is a bad breaker. Hopefully the landlord had his electrician swap out the breaker since a breaker is relatively cheap compared to having the electrician make another service call.
The consequences of a short somewhere are severe enough (i.e. a fire in the walls or other inaccessible area) that it's worth ruling out a short before you leave the circuit turned on. If the landlord can't fix it to your satisfaction, hire an electrician of your own and bill it back to the landlord. Even if it's just a bad breaker, the landlord is responsible for wiring problems.
The fact that it stays on after waiting 5-6 hours probably means that it's not a short, but I wouldn't dismiss any repeated circuit breaker trips since the circuit breaker is your only warning about a dangerous short in the wiring.
When the fridge turns on (some) and when (some) ovens start their capacitors pull a ton of current to start the motor/function needed.
If these are on the same circuit as your TV this is a pretty big issue and the fluctuations could cause damage to your TV circuit board over time.
Even if these aren't on the same circuit your TV is getting a voltage fluctuation from the main circuit. Your TV having intelligence built in probably has its own way of handling these fluctuations - with one turning off some extraneous functions... like HDMI working.
HDMI cables work or don't. If yours is showing a picture then getting a "better" one won't help.
What I would do? First make sure that your TV is not on the same circuit as the fridge and stove. In some places this wouldn't meet code and it certainly isn't good for the electronics.
If they are not on the same circuit then you may need to call the electric company and figure out if they have anything that is causing fluctuations on your line when something high voltage is plugged in. They may fix the issue or offer suggestions - and a lot of times this is free. If the electric company believes it is an issue on your side you will need to troubleshoot why you have this interference - usually a loose connection in the main box.
And lastly you may need to change appliances or tv... Not saying you have to do this but you gave a specific example. Your TV may not handle any kind of voltage fluctuation well. Whenever a major appliance turns on there will often be a little voltage fluctuation. Most electronics are built to handle this. Maybe your TV does not handle this well and your electricity issue is not really a big deal. Or maybe your TV handles this normally and this would happen with all/most TVs.
Question too - do your light flicker or dim during this initially engagement?
Best Answer
If you can find a breaker that controls all the same lights and outlets this would be helpful. If it is just 1 breaker most likely it is a bad hot connection. usually in a junction box at an outlet or light switch but it could be the hot wire that connects to the breaker, very unusual for a breaker to do this but it could be the problem also. Find the breaker and see if some areas turn off that were on when the power goes away that will help narrow down where the problem is. It could be the neutral wire also but I have less problems with these and am not sure why as they normally carry the same current. If you find 1 breaker and additional lights or outlets turn off when you turn the breaker off go to the last working outlet and check the connections there (with the power off) if those are good go to the first non working outlet and check there. If everything is the same when turning the breaker off as the power fail, you will need to remove the dead face of the breaker panel and verify the wire on the breaker is tight, follow the wire back to where it enters the box with a white wire and follow that to the neutral buss and make sure that is tight. the last thing would be to try and replace the breaker looking at the tab to make sure it has not arced and burned the tab the breaker connects to.