REMOTE DOES NOT WORK ON SYLVANIA TV

Question

The remote originally recieved with my 19 inch sylvania tv, purchase in the late 1990's was lost. I then purchased a universal remote which worked for a while and then konked out. I purchased a remote, that claimed to work with all sylvania tvs made after 1988. That does not work with the tv. Then I purchased 3 more universal remotes and none of them work. Does anyone know why this would happen. I have to manually change the channels at this point.