I would have the tubes checked as well, this is usually the problem with age. The speakers are rated to handle the amp so normal usage won't damage them. Check the tubes.

If you cannot hear a his from the speaker when you turn up the volume all the way, there is a good chance you blew the speaker. It can be replaced. If it is not the speaker then it need to go in for service. If you are neer the philadelphia area you can bring it to Pro Line Music 215-736-8055