DVD Player reads Unreliably

On a nice pristine disc this machine sometimes takes minutes of scrapey-sounding noises before it reads and locks onto the next chapter. The lens cleaning disc hasn't helped, and it doesn't seem to do it when playing a disc straight through. It only hangs up sometimes when jumping from track to track. Eventually it always reads the next track and plays the next chapter. Also it has no trouble at all playing CDs. Can it be fixed or is it just old and defunct?