Microscope Maintenance - new problem

I'm in the midst of fixing a bunch of "broken" microscopes and have come across a problem that I've not seen before. I'm a bit leery of just taking it apart in the hope I can work out what to do as its one of our few "top end" scopes, so I'm hoping someone here may have a bright idea as to what has happened or how to fix it.

Problem : The "nosepiece or turret" which houses the objective lenses appears to consist of two parts. With this particular scope the top part is black and is immovable ie fixed to the tube of the scope. The bottom part is silver and holds the objective lenses. This bottom half is moveable and rotates within the top black half allowing the objective lenses to click into place. My problem is that the black part of the nosepiece has become moveable. It is still atached to the tube but swivels from side to side. The silver bottom part of the nosepiece still rotates within the top half and the objective lenses will still click into place if you manoeuvre the whole nosepiece carefully so in theory the scope is still useable.

Now carefully is not a word familiar to a lot of our students whereas frustration is. So to avoid further damage I'd like to gat this fixed. Any ideas?
 
Solved it.It wasnt the central screw on the nosepiece as. on this model, that just reveals the mechanism that allows the bottom half of the nosepiece to rotate in the top half. However I unscrewed all of the lenses (4) and this allowed me to see a retaining ring inside the nosepiece that had two slots in it which could be used to tighten the ring. Our DT guy made me what was in effect a large bladed screwdriver and the scope is now fixed
 

clairelucas

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Any other help with this would be great..
Removing the lenses didn't help me see anything that could be tightened or adjusted, and the central screw between the objectives seems to be as tight as I can manage (though as I haven't dared remove the stage, their might be room for adjustment, but seems solidly tight)
Any other suggestions? Preferably ones that don't require more than screwing/unscrewing, as don't want to wreck a still useable microscope.
Motic SFC-100 series, if that helps..
Thank you!
 
Any other help with this would be great..
Removing the lenses didn't help me see anything that could be tightened or adjusted, and the central screw between the objectives seems to be as tight as I can manage (though as I haven't dared remove the stage, their might be room for adjustment, but seems solidly tight)
Any other suggestions? Preferably ones that don't require more than screwing/unscrewing, as don't want to wreck a still useable microscope.
Motic SFC-100 series, if that helps..
Thank you!
on mine BMS but with a similar design, the black tube has a thread and screws into the turret.

there is also a screw here

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which should let you take the turret off
 
I've just investigated this on one of ours.
On our model, the screw highlighted above by Paul reveals the prism but no access below that.
Just above the nosepiece (between the nosepiece and the screw shown above) there are two allen key type screws which when removed reveal the opposite end of the fixed part of the nosepiece. There appear to be two slots that I guess you could use a large screwdriver to turn (I didn't try this as ours wasn't loose and I didn't want to mend something that wasn't broken). This seems to be the only thing that could be responsible for tightening that part.
Please note though, if you do remove any of these screws it can be a bit of a nightmare to get it lined up properly to put them back in.
 
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