MicrobeHunter.com Microscopy Forum

I have a beautiful Reichert Zetopan. Everything works well except the fine adjustment. It turns, but does not raise or lower the stage. I assume that some part of the internal mechanism is broken or disengaged.

I can use the scope with just the coarse adjustment up to a 40x objective (with difficulty), but I'd really like to get the fine adjustment working, as this will eventually be a gift for my grandson.

I was able to find a working focus block from another Zetopan at a reasonable price. It's the whole unit, complete with coarse and fine adjustment knobs. It looks complete and both knobs move the mechanism properly. I can see the gears turning inside.

I'm tempted to try swapping out the current focus block and replacing it with the one that works. However, I'm a little nervous about it, since a mistake might leave me with a totally nonfunctional scope.

Has anyone done this? Any informed advice? It looks like all that's required to make the swap are a few screws, but I don't know what might be hiding in the shadows.

I'm attaching pictures showing both sides of the working focus block.

Trying again with the attachments:

Just go slow, write notes and don't force anything. You should be ok. Use good screwdrivers that fit...

imkap wrote: ↑

Thu Feb 23, 2023 8:56 am

Just go slow, write notes and don't force anything. You should be ok. Use good screwdrivers that fit...

Exactly. And take pictures. The Zetopan is a brilliant piece of design and manufacturing. Very readily repaired, very logically and precisely constructed. Also if you mess up somehow, there are lots of completely stripped stands available for very little, possibly even for the asking.

I haven't swapped the focus mechanism on a Zetopan, but I did try to do so recently between two Vanox AH stands. To my surprise, the new mechanism would not fit the stand, though they looked exactly alike. Looking more carefully, I saw that the stand had a number stamp ("8") in the casting next to where the block mounts; the original focus block also had an 8 stamp, while the one I was swapping in was a 6. Interesting. They have locating pins in different places. So be aware that there might have been various iterations of the stand or focus mechanism design, or more than one set of parts, making them incompatible. This is not uncommon. The Diaphot similarly has internal prisms that cannot be swapped between all versions of the stand.

^^^ This is "henry's" fourth barely relevant post of the day. Spam buried in it?

Getting back to David - there's often some sort of friction-washer drive on the fine focus mechanism. No idea if the Zetopan has one, but if so, it might be slipping due to dried grease elsewhere? Another possibility is a setscrew that has come loose on a shaft.