Universal remotes are only universal within a certain range of sets, as many types currently available might not contain the codes necessary to operate all brands of TV's, this being where programmable (or learning) types are superior.

You havent mentioned as to whether or not you have tried out all the codes shown in the booklet that came with the remote listed as being applicable to your brand of TV, if however you have then there is the possibility that the remote does not contain a code for your particular model.

It should also be said that "all" universal that can switch a device off or on do not necessarily conform exactly to the command icons on their buttons, if they do then a person is lucky!, as for example a button marked audio mute may well do that on one set but something else on another model, so operations are very erratic with most of these types and nothing can be guaranteed to work.