Can I swap the head and focusing block on this late Zeiss universal? s

[Gatorengineer64]

As the title states would like to swap the head back to an old dovetail style and replace the focusing block with an old black metal one.

I have a nice optvar head in black and this one does not seem to be modular.


OK the focusing block I hate plastic...

Thanks for any input

[ImperatorRex]

Hi,
current equipment fitted to your tube head looks different to what I have seen so far. Also the condensor and table carries are somehow not the standard ones that I would recognize, seems table is special "Pol" version.
I have not switched the different versions of the focus block, but it is worth to try!

Tube Head versions:
I have seen two different tube heads for the Universal II and III:
- the pol slider tube fitted with the Optovar.
- the pol slider tube without the Optovar.

I tried to fit an Optovar pol slider tube to the Tube Head to replace the existing slider tube. However the optovar surface to mount has a small "nose" that does not allow to fit to the assembly surface of the tube head.
So you need to apply some specific machining to make it fit. I do not like that, so I just bought a compete tube head.

But you can try buy yourself:
The black colored head is fixed in the tube head by three small hexagon setscrews (each setscrew is secured by a small pin, so you first need to remove the fix pin and then the set screw). One your fotos I just see one drill hole where this small screws are located inside.
After losening the three screws you can remove the optovar.
When you fit the new optovar you need to take care of correct orientation, also you will need to collimate / bring the optovar into the exact center. This is not impossible, but requires a bit fiddling arround.

[MicroBob]

Usually these heads contain a beam splitter slide with different settings:
- All light to the top port
- All light to the front port
- Split between top and front
- Split between built in camera and front (Phomi)
- All light to the built in camera

So depending on what you want to do there are different optimal options. I use a Phomi I, second edition with a newer Universal head, beacause I get the "Split between top and front" option this way. For quickly moving plancton objects this simply is the most useful setting.

Another question is : Optovar yes/no?
In my view it makes most sense to use such a big microscope if these options are available. With high n.a. objectives it is just nice to have a little higher post magnification available.

[Gatorengineer64]

As a matter of cosmetics, I like this body in gray versus the hammer paint. From a practical standpoint it also has a connection for Epi through the body, much nicer. I am hoping behind the Head Zeiss preserved the same 4 bolt dovetail mount. We will see in a bit.

How does the focusing block come off? this plastic knob one has the 2mm travel limit, the metal one I want to swap it with does not have that limit, so that would be nice.....

[MicroBob]

the metal one I want to swap it with does not have that limit, so that would be nice.....

My metal focus block has his same limit. These were great microscopes and often used a lot and after long use wear can set in and a gear with an uncommon module can wear down. So better keep this one as a backup. I think you can remove the focus block after removing a few screws from the front. There is a german maintenance guide forthis job.

[Charles]

How does the focusing block come off? this plastic knob one has the 2mm travel limit, the metal one I want to swap it with does not have that limit, so that would be nice.....

To remove the focus block, remove the stage and holder. Then remove the two screws on the top plate above the stage/condenser holder. This will allow you to move the stage and condenser holder up and off by using the coarse focus, which will expose the screws holding the face plate. Remove the screws and remove the face plate. This will expose the bolts holding the focus block to the scope. You will need a large long slotted screw driver and a bit of torque to remove the bolts. The hole is deep so the slotted driver needs to be the same size as the hole.

I would keep the current focus block.

[Gatorengineer64]

Thanks for the advice on the head that was easy. . 5 screws and a bit of dremel.

[Adam Long]

Has anyone taken the Universal/ Phomi head apart?

The head slider on my Universal III is very stiff between the first two positions (front bino and split front/ top) and isn't improving with use. I am hoping the 'ears' are just covers but I'm wary of disturbing the alignment. Any advice appreciated, thanks.

[ImperatorRex]

Hi Adam,
I raised the same question in the german forum.
Pls. have a look here: https://www.mikroskopie-forum.de/index. ... #msg192228

I exchanged the slider between two tube heads, inlcuding relubrication etc.
Precautions or even critical is certainly the removal and push back of the slider, if this is not done carefully the slider easily can get stuck.
At least the second time when I moved the one slider into the other tube head it got stuck. Even with rough force it is now impossible to move the slider anymore in the head
But maybe this is because I made the exchange of sliders between two heads and there may be some tolerances or clearances get to small?

Also it requires some re-allignment of the slider, so the optical axis is set properly. It is possible to visually do this setting, you need a good reference target object that you can use as reference to allign. So I have used a object slider that has squares or parallel lines - something like I have showed here:
viewtopic.php?f=24&t=5930&start=60#p71902

[Wes]

Universal/Phomi heads are not readily exchangeable. There are little red/orange/yellow stickers with 3-4 digits on the head and foot (and on the Phomi power supply) that indicate any set of components with the same numbers have been optically precisely matched (and electronically for the Phomi exposure settings). Realignment requires specialized tools like collimators and so on, however its entirely possible to get the job done without these, it would just take a lot more time and swearing

[Adam Long]

Hi Adam,
I raised the same question in the german forum.
Pls. have a look here: https://www.mikroskopie-forum.de/index. ... #msg192228

Jochen,

Many thanks for the link - just the information I need. In the end I got stuck in and figured it out myself but next time I will search the German forum first!

Here is the slider removed and end caps:

IMG_4699D.jpg (128.45 KiB) Viewed 3182 times

Here is a view down the brass tube with the slider removed:

IMG_4700D.jpg (87.82 KiB) Viewed 3182 times

You can see from the extra holes it is the same part for the Phomi. You can also see a tiny dent top left - this was sufficient to jam the slider which is a very precise fit. Not at all what I expecting - I thought the 'ears' of the tube ends would be just covers. I carefully sanded the dent with wet-and-dry paper, used wet to catch the dust, and then carefully cleaned the tube and slider. Now it is much better although I should probably add a little grease. Can anyone suggest a suitable type?

There are little red/orange/yellow stickers with 3-4 digits on the head and foot (and on the Phomi power supply) that indicate any set of components with the same numbers have been optically precisely matched

Yes, mine have matching numbers and I know the history so it has not been tinkered with by amateurs before! Although it seems to me removal and replacement of the slider alone should not cause any alignment issues. As long as the tube itself is not disturbed the position is governed by the rail with detents. In any case prisms should not be sensitive to centration issues like the lenses.

[75RR]

How does the focusing block come off? this plastic knob one has the 2mm travel limit, the metal one I want to swap it with does not have that limit, so that would be nice.....

Can you post a photo of your 'alternative focus block?

Note that the original one with metal knobs (that the WL, Universal and Photomicroscope share) has the same 2mm fine focus range