[MORPHEUSP]

it's a weird problem, but why do you want to put a ups for your tv? i use a ups for important stuff for my pc and my console only, but for your problem i would try:

Try the TV alone and test the UPS:

to do so connect your tv to your ups only and your ups to the electricity, turn both on, then when the tv is on leave it for about 10 min, during which flip channels let it heat up a bit to raise the consumption, then press the power button (without holding) on the ups for a bit, in PCE this is called the ups test method, it will simulate a power cut, now theoretically it should be able to hold it out and not turn it off. If problem occurs it might be the battery of the UPS or your TV needs a SINE-WAVE (commercial name : True sine UPS) ups to function with.

Try the different ports on the ups you know on a 1200VA i think there are 3 or 4 ports try em all, maybe a port is defective, also check the connection between the UPS and the device maybe there is a problem with the cable.

now if the TV worked fine let's say only via the port that the ps is connected to, use a rallonge with a ups tip and connect both to it.

in the extreme case you don't need a ups for your TV, i wont help you alot, unless you spend more than 6 hours on TV daily.

if you have power meters it would be wise to use em to check the real consumption of each unit.

hope this helps in any way