Sorry about singling out this one post, but giving advice to LIE when visiting another country is not the wisest advice in the world. Each country has their own laws, and lying on customs/immigration forms, which are official government documents is hardly advisable. It is against the law, and you are subject to substantial fines as well as jail time. In simple words DO NOT LIE on government forms.
The vastly smarter advice is Sweetness' take on things. Why are you bringing down a TV in the first place? Why not buy one here. At Courts you can get a brand new flat screen TV for under $200us. If you buy it here in Jamaica - you are not only NOT breaking the law by lying on your customs/immigration forms, but you are also helping out the local economy by purchasing the TV here.
If you want to buy a used TV, there are several shops in Negril and Sav La Mar where you can get one.
Please do not heed the horribly bad advice to lie on official government forms when entering ANY country...