Full servicing of a NACHET NS400

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ker2x
Posts: 93
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Full servicing of a NACHET NS400

#1 Post by ker2x » Sun Dec 26, 2021 8:28 pm

I got a Nachet NS400 for dirt cheap but it was very poorly handled by the previous owner.
It's not fully broken, some part are FUBAR, some part works, and it's just dusty everywhere.

If you understand French (I do), the manuals can be found here : http://chicheret.free.fr/Microcosmos/Microscope.html
I don't have all the options, only the polar filters (and the objectives (apparently) specific to Nachet)

it's going to be a long thread, so I'll start with some pictures.

A general view :
Image

The easy part : the trinocular is totally FUBAR. it been pierced for some reason and there is glue junk everywhere.
I have 0 hope to repair it and won't waste time on it.
Image

It's covered with some junk plastic but it need a bit of dust cleaning :
Image

Another part I'm not planning to repair, the polar filter (still kind of useable) overheated, and need cleaning (everything need cleaning) :
Image

The very first thing I need to change is the power supply.
The one I got with the microscope was a fire hazard, so I replaced it with something that won't kill me but it's still not good.
As far as I know, the halogen lamp is 12V 100W and waaaaay too overpowered. I think the original (from Nachet, not the fire hazard I got from the previous owner) had a dimmable transformer. according to the manual it could be gradually adjusted from 9V to 12V. The full power probably was for the trinocular output and film photography (It even had a polaroid option).
What do you think about replacing the temporary transformer with a lab power supply (with adjustable voltage, current limiter, and all the fancy stuff lab PSU have) ? I'll have other use for a lab psu anyway.
Image

And perhaps replace the halogen with LED in the future ? Right now, it's so overpowered that I need to insert all the ND filter I have as well as close the diaphragm very close to the limit in order to not go blind. It's not a pleasant experience and that's why I don't do much microscopy yet... I still need a useable microscope ^^

ker2x
Posts: 93
Joined: Sun Dec 26, 2021 7:21 pm

Re: Full servicing of a NACHET NS400

#2 Post by ker2x » Sun Dec 26, 2021 8:44 pm

By the way, I found an English manual : http://chicheret.free.fr/Microscopie/Do ... nglish.pdf
(remember that I don't have all the options shown in the manual so don't get your hope up)

About light and transformer, from the manual :
When switching on the transformer turn the rheostat con­ trol to its lowest setting before increasing the voltage. This will ensure a longer bulb life.
Switch the 6V-12V voltage selector to the 12 V position. Turn the lamp on by switching to position M.
Rotate the rheostat control to regulate the light intensity. Do not go beyond 12 V.
HALOGENE BULB 12 V 100 W
The light source is a low voltage 12 V 100 bulb operated through a transformer.
At 9. 5 V the life of the bulb is greatly prolonged.
Below 9. 5 V a blackening of the bulb will occur.
Obviously it's not meant to be used at full power all the time and that explain the melted polar filter and how blinding it is.

Anyway...
Luckily, I got some good objective with it.
The bad news is that as far as I know, it's specific to Nachet
Any idea what PI FI mean ? perhaps it's PL FL ?

Image
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i also have some weird unusable lens plugged in :
Image
Image
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The condenser ? it can be moved in and out :
Image
Image

The aperture control and some "other stuff" :
Image

Light housing with 3 filters inserted (1 IR blocking, 1 neutral, 1 green-ish to correct the red halogen spectrum) :
Image

Good stuff, huh ? if only it wasn't in such a poor state.

apochronaut
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Re: Full servicing of a NACHET NS400

#3 Post by apochronaut » Sun Dec 26, 2021 9:52 pm

Likely it means plan fluorite. That's a potentially excellent microscope. The 100 watt illuminator does give you the potential to use some very fine contrast enhancement techniques at higher magnifications. Looks like it has a centering nosepiece as well. Couldn't be nicer.

You have a couple of pedestrian 160mm tube length objectives in there that probably won't give you a very good image.
Last edited by apochronaut on Mon Dec 27, 2021 3:46 pm, edited 1 time in total.

ker2x
Posts: 93
Joined: Sun Dec 26, 2021 7:21 pm

Re: Full servicing of a NACHET NS400

#4 Post by ker2x » Sun Dec 26, 2021 9:58 pm

Dust cleaning partially done.

Image

The parts circled in green has been lightly cleaned with dry non-woven sterile compress (I have a bunch of it from my hand surgery)

The front lens of the ocular was dusty and was 90% of the dust that could be seen.

About the part circled in blue (which could be seen in the previous photo of the butchered trinocular) :
Harmless, luckily it was in the right position and the dust was deposited on the black paint of the prism. I won't use the trinocular anyway (I wish I could but you do with what you have)

there is still some large particle on the part circled in red BUT : it's 2 reticles + 1 blank. The blank one is clean. I won't attempt to clean them as I'm totally happy with the blank one as I won't use them anyway. They're frames that appears to be related to photography frame for the optional nachet fotomat thingy. (even if I had it, I wouldn't use it anyway. I'm not a fan of film photography)

I guess the cleaning is pretty much done for now.

ker2x
Posts: 93
Joined: Sun Dec 26, 2021 7:21 pm

Re: Full servicing of a NACHET NS400

#5 Post by ker2x » Sun Dec 26, 2021 10:09 pm

apochronaut wrote:
Sun Dec 26, 2021 9:52 pm
Likely it means plan fluorite. That a potentially excellent microscope. The 100 watt illuminator does give you the potential to use some very fine contrast enhancement techniques at higher magnifications. That looks like it has a centering nosepiece as well. Couldn't be nicer.

You have a couple of pedestrian 160mm tube length objectives in there that probably won't give you a very good image.
The "pedestrian" 160mm lenses does't give a "not very good image", they give "no image at all" as the microscope need infinity lens. And they appear to be crap anyway so I don't care.

As far as I know, the centering is still good. I hope :)

There are actuator to center the diaphragm too and I centered it.

There is also a sliding "Bertrand lens", I don't know how to use it.
BERTRAND LENS
The Bertrand lens allows a magnified image of the back aperture of the objective to be examined enabling : -
1) The aperture iris diaphragm to be correctly set with regard to the numerical aperture of the objective.
2) The Phase annuli and phase rings to be adjusted to obtain exact coincidence.
3) Inspection of the interference figure in Polarized light work.
To operate the lens push in the slider (1) and focus with milled wheel (2).
I also don't know how to use the complex "unversal condenser". it can be moved up/down and part of it can be stowed away as can be seen on the 2 pictures :
(PS : the picture were before the cleaning :D)

Image
Image

ker2x
Posts: 93
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Re: Full servicing of a NACHET NS400

#6 Post by ker2x » Sun Dec 26, 2021 10:21 pm

From my understanding of the manual, the only "option" I have is the one for "interference contrast" seen in "part 5" of the manual : http://chicheret.free.fr/Microscopie/Do ... nglish.pdf

apochronaut
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Re: Full servicing of a NACHET NS400

#7 Post by apochronaut » Sun Dec 26, 2021 10:31 pm

The swinging top lens of the condenser is swung out of the way in order to lower the condenser N.A. and also therefore increase the diameter of the illumination circle. This gives a full illuminated field coverage of low power objectives : 5X and below. The top lens is used swung in for 10X and up.

A bertrand lens lets you view the back focal of an objective and thus assists in some adjustments , especially the alignment of phase rings. It is sometimes useful in BF but not often used. It can help you view the field diahragm centering and adjustment.

ker2x
Posts: 93
Joined: Sun Dec 26, 2021 7:21 pm

Re: Full servicing of a NACHET NS400

#8 Post by ker2x » Sun Dec 26, 2021 11:41 pm

apochronaut wrote:
Sun Dec 26, 2021 10:31 pm
The swinging top lens of the condenser is swung out of the way in order to lower the condenser N.A. and also therefore increase the diameter of the illumination circle. This gives a full illuminated field coverage of low power objectives : 5X and below. The top lens is used swung in for 10X and up.

A bertrand lens lets you view the back focal of an objective and thus assists in some adjustments , especially the alignment of phase rings. It is sometimes useful in BF but not often used. It can help you view the field diahragm centering and adjustment.
thank you very much for the info.

It is now "clean enough to be useable". The objectives have a little bit of dust. I don't think I have the proper solution for that.
I have 70% medical alcool for disinfection, with added "chlorure de benzalkonium", it's yellowish and it doesn't sound like a good idea to use it to clean lenses.
I'll try to find a more appropriate liquid.

Tested all 3 lenses. also played with the polarization filter near the end (it appears to be partially melted but it's still useable somehow)


Hobbyst46
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Re: Full servicing of a NACHET NS400

#9 Post by Hobbyst46 » Mon Dec 27, 2021 8:14 am

From the video, that is a decent start, on the way to a very nice setup !
I would try to improve the illumination, prevent uneven brightness and vignetting: condenser adjustments (Kohler).

MichaelG.
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Location: North Wales

Re: Full servicing of a NACHET NS400

#10 Post by MichaelG. » Mon Dec 27, 2021 9:29 am

ker2x wrote:
Sun Dec 26, 2021 8:44 pm
By the way, I found an English manual : http://chicheret.free.fr/Microscopie/Do ... nglish.pdf
(remember that I don't have all the options shown in the manual so don't get your hope up)
Thanks for the link to the manual : You have a fabulous instrument there !

Wishing you well for a successful restoration
MichaelG.
Too many 'projects'

ker2x
Posts: 93
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Re: Full servicing of a NACHET NS400

#11 Post by ker2x » Mon Dec 27, 2021 11:00 am

A video for a general overview of the NS400


ker2x
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Re: Full servicing of a NACHET NS400

#12 Post by ker2x » Mon Dec 27, 2021 11:02 am

Can you tell me if the objective mount is standard or not ?


ker2x
Posts: 93
Joined: Sun Dec 26, 2021 7:21 pm

Re: Full servicing of a NACHET NS400

#13 Post by ker2x » Mon Dec 27, 2021 11:18 am

For the cleaning I have in my closet :
- rubbing alcool, as seen in the video. won't use it.
- Ammoniac (I don't think I should use it :D )
- Acetone. Might works ? It's full metal (and glass, of course). But the objective appear to be fluorite so it might require additional precaution ? I don't know if the front lens is fluorite or not and I probably have no way to know.

Hobbyst46
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Re: Full servicing of a NACHET NS400

#14 Post by Hobbyst46 » Mon Dec 27, 2021 12:18 pm

ker2x wrote:
Mon Dec 27, 2021 11:18 am
For the cleaning I have in my closet :
- rubbing alcool, as seen in the video. won't use it.
- Ammoniac (I don't think I should use it :D )
- Acetone. Might works ? It's full metal (and glass, of course). But the objective appear to be fluorite so it might require additional precaution ? I don't know if the front lens is fluorite or not and I probably have no way to know.
The only alcohols that are appropriate are 70-100% isopropyl alcohol -preferably - or ethyl alcohol {ethanol}. In both cases, if the liquid contains anything besides the alcohol and water, do not use it.
Do not use ammoniac on a microscope. Ammoniac like acids, and like Chlorox-like substances, is corrosive. Never use corrosive liquids.
Acetone should be used only on unpainted metal parts, and should not be used near any glass part in the microscope, since it can dissolve the glues within the optical pieces.
I general the best sequence for cleaning is:
a. brush/blow away dust
b. exhale on glass surfaces (IF they are still stained) to form a layer of condensed water and wipe it off with a KimWipe or lens tissue, single wipes and not rubbing. Q-tips are also good.
Never touch a glass surfaces with a dry tissue of any sort.
c. remove stains, old oil and grease with petrol ether/heptane/octane/white benzine/isopropyl alcohol. To do it, wet a KimWipe or Q-tip with the liquid - just a drop! - and wipe once without rubbing.

Clean glass surfaces only if they are visibly soiled/stained/oily. Avoid too much cleaning.

ker2x
Posts: 93
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Re: Full servicing of a NACHET NS400

#15 Post by ker2x » Mon Dec 27, 2021 2:14 pm

I'll post the video where i accidentally discovered this problem while investing another problem.
But I appear to have a found a broken lens while back focusing on the filament using the Bertrand lens.

It's on the illumination path, not between the eyepiece and the sample so it doesn't really disturb the sample observation.

Image

ker2x
Posts: 93
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Re: Full servicing of a NACHET NS400

#16 Post by ker2x » Mon Dec 27, 2021 2:35 pm

i removed the light house and couldn't see any broken lens. Could be a side effect of the misaligned iris ?

Hobbyst46
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Re: Full servicing of a NACHET NS400

#17 Post by Hobbyst46 » Mon Dec 27, 2021 3:25 pm

ker2x wrote:
Mon Dec 27, 2021 2:35 pm
i removed the light house and couldn't see any broken lens. Could be a side effect of the misaligned iris ?
It appears that the field aperture is off-center; that is, the condenser should be centered. Perhaps what you see is a shadow of the sub-condenser ring (filter carrier) not completely in the light path, or some other obstruction. Does not look like a broken lens.

ker2x
Posts: 93
Joined: Sun Dec 26, 2021 7:21 pm

Re: Full servicing of a NACHET NS400

#18 Post by ker2x » Mon Dec 27, 2021 4:05 pm

Hobbyst46 wrote:
Mon Dec 27, 2021 3:25 pm
ker2x wrote:
Mon Dec 27, 2021 2:35 pm
i removed the light house and couldn't see any broken lens. Could be a side effect of the misaligned iris ?
It appears that the field aperture is off-center; that is, the condenser should be centered. Perhaps what you see is a shadow of the sub-condenser ring (filter carrier) not completely in the light path, or some other obstruction. Does not look like a broken lens.
now that I think about it, when I restested with the Ikea instead of the halogen, I didn't have any filter inserted (since the filter are in the lighthouse).

ker2x
Posts: 93
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Re: Full servicing of a NACHET NS400

#19 Post by ker2x » Mon Dec 27, 2021 6:10 pm

The problem I found with the condenser/stage (couldn't upload the video sooner) :


now that I'm watching the video, it's obvious where the shadow come from :D
I still have to fix the focusing problem however

ker2x
Posts: 93
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Re: Full servicing of a NACHET NS400

#20 Post by ker2x » Mon Dec 27, 2021 7:10 pm

Problem fixed. I moved the lower stage up against the upper stage. done.
I can do a proper kohler illmunitation now

ker2x
Posts: 93
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Re: Full servicing of a NACHET NS400

#21 Post by ker2x » Mon Dec 27, 2021 9:51 pm

i browsed some French info :
- Nachet have a 200mm tube
- They kept the same threading when switching to infinity, it's the "RMS threading" standard

So I'm not limited to finding some rare Nachet objective. I can buy pretty much from any manufacturer, including noname.
I have a 4, 10, 25, I could get a 40x... later.

It seems I won't be able to do Dark Field with a simple home made filter, it appears to need something between the 2 diaphragm.

I finally found the name of technic using the 2 polar filter, from the English manual : INTERFERENCE CONTRAST (TRANSMITTED LIGHT)

I can't really find info about it. google send me to DIC. is it the same thing ? doesn't look like it.

rmb
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Re: Full servicing of a NACHET NS400

#22 Post by rmb » Fri Dec 31, 2021 4:03 pm

I know some will baulk but i quite often wash dusty bits if they are detachable. i use a dilute solution of a non residue leaving detergent made by bilt and hamber for cars of some squirty hand soap and rinse copiously under the tap. difficult but not impossible for eyepieces and light port glass, coloured filters
Careful application of a vacuum cleaner with a dusting nozzle gets big bits off - but also eats parts of the scope if you arent watching
For objectives and sensitive glass surfaces i use something called Firstcontact from Stanwax Laser. you paint it on and peel it off when dry. it isnt cheap for a wee bottle but it means no abrasion of a glass surface. I see they are infinity objectives - maybe some american opticals would work on this

ker2x
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Re: Full servicing of a NACHET NS400

#23 Post by ker2x » Fri Jan 07, 2022 7:27 pm

Well...
  • I received my power supply, it work and serve its purpose but it have a major defect, so I'm returning it and wait for a new one (same model).
  • I found a supply of 99.9% isopropyl alcool at a local drugstore, as well as distilled water. latex glove too.
  • i sealed the Trinocular output (a temporary solution of course) as I won't be able to fix it anytime soon. despite my best effort I can't find the type of mount. seems proprietary.
  • I learned to sew so I'll make a cool cover for the microscope, dust keep accumulating
The quest continue.

Hobbyst46
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Re: Full servicing of a NACHET NS400

#24 Post by Hobbyst46 » Fri Jan 07, 2022 8:39 pm

using a sheet of white paper :
I determined that I have a clear in-focus projection of the sample at a 16cm distance from the Trinocular mount.
The distance vary greatly with the focusing. but if I want both the eyepiece and the camera in focus at the same time, it appears to be 16cm
I believe that is progress and you will find how to couple a camera. Say, for direct projection coupling, without eyepiece, all that is needed is a mechanical tube including a helicoid focuser, without any glass inside. As long as it can be axially connected and provide a top flat surface, to attach (even by glueing) a simple camera mount adapter.

viktor j nilsson
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Re: Full servicing of a NACHET NS400

#25 Post by viktor j nilsson » Fri Jan 07, 2022 8:42 pm

I would totally just glue a M42 ring on trino port in this case.

ker2x
Posts: 93
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Re: Full servicing of a NACHET NS400

#26 Post by ker2x » Sun Jan 09, 2022 1:08 pm

  • I received the replacement PSU (the previous had had a defect) so I have proper light again :)
  • i have to dim my 12V halogen to 8V to be able to use it with the 4x objective, I think I'll buy a 75W halogen or whatever exist between 50 and 100. a large under voltage will darken the bulb so it's not good (I heard it's reversible however)
  • I found how to center the condenser so I fixed the off center diaphragm problem
I really need to clean the lenses.
Also, I made a video to celebrate. 99.9999% of the crap is in the sample, but I still have some crap on the lenses too. (mostly on the condenser, it's very visible so I have to defocus it but I don't haver proper colder illuminaton anymore)

Last edited by ker2x on Sun Jan 09, 2022 2:41 pm, edited 1 time in total.

Hobbyst46
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Re: Full servicing of a NACHET NS400

#27 Post by Hobbyst46 » Sun Jan 09, 2022 2:34 pm

Nice to see the progress !
The video does not show which is "dirt" irrelevant of the specimen.
Usually the condenser is not in focus with the specimen and "dirt" on the condenser is seldom visible (IMHO).
I would only clean what I definitively identify as "dirty".

ker2x
Posts: 93
Joined: Sun Dec 26, 2021 7:21 pm

Re: Full servicing of a NACHET NS400

#28 Post by ker2x » Sun Jan 09, 2022 2:43 pm

Hobbyst46 wrote:
Sun Jan 09, 2022 2:34 pm
Nice to see the progress !
The video does not show which is "dirt" irrelevant of the specimen.
Usually the condenser is not in focus with the specimen and "dirt" on the condenser is seldom visible (IMHO).
I would only clean what I definitively identify as "dirty".
yeah it's "clean enough to me" for now. it will be more problematic when I'll be skilled enough to make clean sample. not anytime soon :D

ker2x
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Re: Full servicing of a NACHET NS400

#29 Post by ker2x » Tue Jan 11, 2022 7:53 pm

It's not much but I feel like I've achieved a usability milestone, and I'm happy

Image

BramHuntingNematodes
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Re: Full servicing of a NACHET NS400

#30 Post by BramHuntingNematodes » Wed Jan 12, 2022 1:57 am

Congrats, it's beautiful
1942 Bausch and Lomb Series T Dynoptic, Custom Illumination

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