I might be inclined to think that also if it wasn't that ALL the objectives on all the microscopes of this style that I have don't budge. I have a couple nicer ones where the objectives do unscrew. And I've seen various websites describing their student microscopes as being "student proof" because of "locked-in" eyepiece and objectives.
I'm not a wimp and I know which way to turn. They aren't budging. But I'm going to try removing the screw in the center of the turret, between the eyepieces, and see what happens. When I get time for it...
Sorry wasn't trying to imply anything. Just trying to cover the bases. One thing to note, at this magnification the focus distance is an extremely small window of distance. It is quite easy to go right thru the point of focus. I'm sure you know this, I just point this out to others who may read this thread.
If they are locked I would have to agree with others above that they may have used a locking compound since there are no set screws.
Have you tried looking at the objective with a loupe? The objectives are probably cemented and the cement may have failed. Of course this is a lot easier to do from the backside of the objective.
I have close to 10 student microscopes that came from colleges, never once have I found a locked objective. That's why I was so surprised that others have run across this, quite interesting. And yes I really need to thin the herd. (I say this after buying another AO model 10 this week)
In my defense the student microscopes are all AO and I use these for objectives and any other parts I may need to support my research grade scopes. Three that I'm rebuilding currently.
this one I bought for the condenser and the stage.