At my school, we are having a bunch of problems with our Ellipsoidals. We are using the altman 1KL series of fixtures. These fixtures are of varying degree measures. Recently, about half of these instruments are no longer operational, We have tried swapping bulbs, but this doesn't work. I believe that the sockets are to blame. Which would be more likely to happen in a public school. Buying the necessary parts to repair these fixtures, or upgrading?