If the tray will not lift it's usually due to the belt/band. It's probably too loose. You can replace the belt with an o-ring from the auto parts store, make sure it's got some slack, but a snug fit. The old belt is probably too weak to lift the laser assembly. I have seen this before. The gears are usually not the issue. It's hard to explain but once you have the gears set a certain way everything sort of aligns itself. The engineers did that so that if you push or pull on the tray by hand, it should be able to reset it'self back into the neutral position. There is only one way that it all fits together. Usually the issues with a model 1 are either the belt, the laser, or the fuse.
Sometimes there are other problems like broken mounts and hinges which you should keep an eye out for as well.
There is a thread about a recent repair a friend and I did on Digital Press. You can read about it here:
http://www.digitpress.com/forum/show...-1-Tray-Issues