Stage disassembly

[Sauerkraut]

Any pointers or words of caution for disassembling a stage assembly? In a nutshell, the X-Y control knob assembly is loose, and starting to cause issues with gears not meshing well. At first I thought it might be a lube issue but after lubing all and reinstalling the stage on the scope, I can now see that the issue is the X-Y shaft is loose. See images. Removing the 2 allen screws holding the plate of the X-Y shaft did not allow the whole geared assembly to pull out, tho I did not strong arm it. And tightening them did not remove the play. The plate itself is not moving. It's at the base of the plate where the shaft goes through it.

There are ball bearings to deal with in both planes - don't know of they are captive or will go loosey goosey at some point during disassembly. My hope is with the shaft removed, there will be something that can be tightened to remove the play.

Thank you for any pointers. This is a stage off a OM139 - standard Chinese scope.

Heather

[Hobbyst46]

This might be looseness between the shaft and the rack. If Omano copied old Olympus stages from the AH, BH era (40-60 years ago) the shaft was might be exposed and reached by disassembly of the knobs. So, I would look for locking small screws around each of the X-Y knobs.

[Sauerkraut]

Update - just got the XY gear assembly out. Shouldn't be a need to disassemble the stage after all.

[Hobbyst46]

Bravo, you again solved mechanical problems It may help other microscopists to know the details, photos of the parts, etc, since so many folks depend on their own skill and ability to repair their used scopes, and repair manuals are rare to non-existent.

[Sauerkraut]

Well getting the XY assembly out was embarrassingly simple - I just removed the small linear gear plate and it came right out.

I did learn a few things though. There is a spring inside that XY assembly that moves the lower knob in the horizontal plane toward the upper knob. Function unknown, but it did help to move that up and down and free up the X shaft from the Y shaft by using WD40. That got everything freed up, but it did not solve the problem with slop/play.

To fix the play, there is a bushing on the XY knob shaft that sits inside the stage housing, and it's undersized from what it should be, allowing the whole unit to spin and/or have slop, rather than rotating the desired circular X gear or Y gear. And it also give an unpleasant grinding feeling in your hands. The fix, in the absence of having a perfectly sized bushing, was using a tight wrap of thinly cut electrical tape around the bushing to build up its size, though there must be better ways of accomplishing this goal.

I did also shim up one of the linear gear plates with washers for a better gear meshing pattern.

The stage feels like new, leaving me still seeking a valid excuse to get another microscope.

[75RR]

The stage feels like new, leaving me still seeking a valid excuse to get another microscope.

How about furthering the education of a favorite niece or nephew?

[Sauerkraut]

Come on over nieces and nephews! Check out my...er, I mean your new DIC microscope!

[75RR]

Come on over nieces and nephews! Check out my...er, I mean your new DIC microscope! ;)

I meant donate your microscope to a niece or nephew. That would get you both brownie points and an excuse to get another microscope. :)

[Sauerkraut]

Come on over nieces and nephews! Check out my...er, I mean your new DIC microscope!

I meant donate your microscope to a niece or nephew. That would get you both brownie points and an excuse to get another microscope.

Good idea! Though I did just order a cardioid DF condenser for it - upcoming experiments in frankensteining parts together on tap soon.