A new circuit board for an led TV costs around $100.00 to $150.00 and it's usually not worth the cost of buying a circuit board for the TV depending on the age of the TV.
If it was a very expensive TV then it might be worth the cost to replace the circuit board in the TV but for a cheaper model it's usually just as cheap to buy a new TV.
If you pay a repair shop to install the new circuit board then it may cost you $200.00 to $300.00 for the repair which is usually the cost of a new TV depending on the size of TV you have.