Spring loaded objective stuck

Doc.Al · Post by **Doc.Al** » Wed Jan 19, 2011 9:28 am

Hi,

I have recently purchased an Olympus A40PL objective (LB series) where the spring-loaded front of the lens has become stuck in.

Does anyone know of a simple solution to freeing up objectives that have been stuck in this way.

The objective can as part of a set and I would prefer not to have to return the whole set.

Thanks

Alex

g4lab · Post by **g4lab** » Thu Jan 20, 2011 1:50 am

It probably has immersion oil polymerized in the barrel.

You can probably free it by VERY carefully flushing that part with extremely clean xylene.

If the barrel cover unscrews you might get a better view of the offending area.

Gary W Brown · Post by **Gary W Brown** » Thu Jan 20, 2011 7:22 pm

You will need a set of jewelers screw drivers to disassemble this objective.
Use a smaller one to carefully remove the rubber grip ring from the barrel of the objective. This will expose a small phillips screw which you can remove. The back cover can then be removed and the spring can be removed. Set the objective on your bench with the threads down and with your thumbs apply firm pressure to the sleeve which holds the glass. More than likely, the inner tube will dislodge and slide down. It may take a little effort to get it pushed through. Besides the possible dried oil there may also be burrs on the outer sleeve or the inner tube. Once you determine the cause of the bind and repair or correct it you can re-assemble the objective. If none of this works, get out the magic hammer.

Doc.Al · Post by **Doc.Al** » Fri Jan 21, 2011 7:01 am

Thanks for both responses. I will have a look at it tonight.

Choronzon · Post by **Choronzon** » Fri Jan 21, 2011 4:48 pm

Also check for signs of saline corrosion. If the optic was used in profusion experiments, or patch clamping, it could have corroded retraction mech. A water based solution like lens cleaner can sometimes unstick these, but it's difficult and time consuming. Immersion oil doesn't really hard stick objectives any more, as they're non drying these days. Also the optic could just be jammed. into a retracted position.