Tv brightness rf adaptor help

okay so i put on in this thread because a tv is technology soo a while ago i bought a rf adapter and it works great except…
it works amazing on my families 32" tv and my parents 20" tv but on my 16" tv it works fine but its so dark. its around 13 years old and i do not have the remote for it does anybody know if there is universal remotes for tvs of this age?