Can't identify the problem with my lcd tv

The TV is probably (but not limited to) having problems with the power supply.

the possibilities are that

1 .. the power supply is having problems starting up due to a fault within the supply

2 .. the power supply is having problems starting up due to excessive load causing it to trip out.

I do not know the particular brand or model, but experience dictates that the best place to start search is by thoroughly examining all areas of all boards for swollen or leaking capacitors. Anything that looks like it might be anything other than a perfect flat topped capacitor is suspect and should be replaced with a capacitor of the same type, voltage , capacity and temperature rating. I prefer to change all capacitors that are 85 degrees celsius for 105 degrees celsius.

If a capacitor needs changing but you can't find something of the same value and voltage rating .. ALWAYS take the next value larger .. so if you have a capacitor that is rated 6.3Volts .. but can't find one .. use 10 Volts or more NEVER use one that is rated less than the original .. it will fry very quickly ad probably cause a few more problems as well!
If you need a 270uF capacitor then a replacement would be 330 uF or even 470uF. Take care not to go too high .. that can cause other problems too .

Preferably, if you don't know about Electronics,

DONT OPEN THE TV AT ALL!!.

There are lethal voltages inside that can kill even if the set is switched off!

Since I have no idea at all of what is inside this particular model .. I just couldn't say ..

Point is that the power supply is probably tripping because the main circuitry wants more "power" at start up than can be given .. which could be because of a problem in that the power supply has a fault and can't give .. or that another circuit is faulty and is demanding more from the power supply than it was designed for ..

Some companies sell replacement boards once you realise where your problem is

From experience, unless you go to the manufacturers workshop, a repair will take some time to figure out and fix. The manufacturers usually have spare boards that they use for trouble shooting which means that they swap out boards until the set starts working, then start replacing the boards again ..
If it's a well known fault they will know what to do ..
If you go to an independent repair guy he will have to diagnose everything, starting from the power supply and working through different boards until he finds the problem.
If he has had a set like it before , it will be quicker, but since you say it's possibly an import then it's quite likely that it NOT be an easy job .. all depends upon whether its independent modules or a single board, what experience he has etc also what sort of components will be found to be faulty .. it may be something very simple .. but more likely it will be age related .. If it's capacitors then he will need to source them, .. on one motherboard that I get in frequently for repair I have to replace a minimum of 22 capacitors each time .. that takes time .. then I have to test .
If the problem is due to inverter or display panel, It won't be a cheap repair .. in fact it's usually cheaper to buy something new as a replacement than repair it.

I would start asking around the repair shops if I were you , but again you probably won't get much of a useful answer. I and a lot of my colleagues have been caught out far too often to put a "price" on a repair. Sometimes there is a secondary problem hidden by the original problem that shows when the equipment comes in .. we fix the obvious but then find the hidden .. that can make or break the possibility an economical repair! and that's why we refrain from putting a price on something that is unknown. Sometimes it can also take several days tracking down components only to find that due to scarcity , the price may also have jumped from $10 to $100