I used TurboTax last year. It had a section for donations where it figured out the amounts of the IRS approved values for a donation.
You would need to know the size of the television and the current condition it is in.
He's a screenshot - though it's not from the TV section.
TurboTax offers a free online tool called ItsDeductible that does the same thing (though I haven't tried it).
Unfortunately, I don't have the current one with TV's to give you the range of amounts that apply to yours.
--I am not affiliated with TurboTax and did not receive it for free for a review.