Why so complicated light source old Zeiss ?

[Kalleboy]

Hello
Old Zeiss microscopes 1970-1980
Has an old Narva bulb 6V 5W or so...
The light from the bulb goes through a diameter 45mm round mirror (which is placed at 45*degree angle) which was a bit scratched because when shipped it fell off and rattled inside the case (DDR's 40 year old glue failure due shipping)...
Pos.18.) Umlenkspiegel Ø45mm fur Zeiss Laboval 2
- So must the mirror be 100% free off any scratches or will a mirror with small scratches function properly ?
-> If I replace the mirror can I just buy any Chinese round mirror ? Or does it have to be laboratory quality special mirror ?

Since Narva bulbs aren't produced anymore. I have been thinking about placing a more modern halogen light bulb base to it or LED...
What if I place a hillbilly: direct LED Flashlight as a light source ?
- Why must it be behind mirrors and such complicated casing ?

[75RR]

So must the mirror be 100% free off any scratches or will a mirror with small scratches function properly ?

Are the scratches causing a problem? Can you see them when looking through the eyepiece?

[btschumy]

If you scope can be set up for Kohler illumination (look it up if you don't know how) then the mirror scratches should not be visible when the subject is in focus. Their effects should be minimal.

My mirror was also badly scratched from improper cleaning when I purchased it. The scratches are not a serious problem. Nevertheless, I have ordered a 1st surface mirror off eBay which I will cut and replace the scratched mirror.

You can try an led flashlight for illumination and see how it goes. My guess it it won't be very satisfactory.

[Kalleboy]

Nope can't see any of them. How can I make them visible if somehow present ?
How many lumens does microscope need ?
- Will too powerful light damage eye because lenses magnify it to "sun power" ?

Kohler illumination= Don't know if Laboval series have it. I know it has Abbe Condenser ?

[75RR]

Kohler illumination= Don't know if Laboval series have it.

Are you using your microscope yet or are you still setting it up?

Practice Köhler with the tutorial:

http://zeiss-campus.magnet.fsu.edu/tuto ... flash.html

[apochronaut]

Is it this unique 15w. bulb with the threaded end? http://www.ebay.com/itm/MICROSCOPE-PART ... a-Kbrosope.

These are new from surplus but for sure , some microscope bulb suppliers will still have them. Microlites in Toronto still had them, last time I needed one to service a Jena stand. Some of the other bulbs that Jena used are made by other mfg. This one was only made by Narva,. Possibly someone else has picked it up, though. You could convert the socket from the thread type used for the Narva to a bi-pin for the Philips type 13347Z, which has the same size and output bulb, just with a different base.
converting to led is complicated and is often a failure due to unrealized differences in the illumination characteristics.

[Kalleboy]

http://medind.nic.in/haa/t01/i1/haat01i1p63o.pdf
Zeiss Laboval 2, DDR Jena uses
Screw type 6 V, 5 W Tungsten filament
(Ergaval uses 15W)

NARVA 67123 Zeiss ZENTRIERFLANSCH 6V 6W Z*art.n. 068.376 *art.n. 688.61/4
DAS 24 / DAS 240 FS 10/FS 11 Industriespektroskop Leukometer Pulfrich-Refraktometer PR 2
Specord UV-VIS, VSU 1, Laboval 2, Laboval 2 afl., Laboval 2 pol., Eduval 4 (2. Ausrustung)

[apochronaut]

I thought it must be a typo. 5w. is remarkably low. They must have been doing something right. Is the bulb, right under the stage?
I do see listings for Narva bulbs, from Eastern Europe suppliers; CZ., Bulgaria, Poland. The prices are better than microscope bulb suppliers here. One place in the U.S., wants 86.00 for that bulb.

[PeteM]

Not sure what Zeiss model you have, but one of the scopes I picked up for our kids' science program was a Zeiss "Standard." Would have to check the bulb this originally came with but it sounds much like yours.

Replacing the whole bulb assembly with LED illumination was very easy, if you have a good friend with a metal lathe. Basically the old bulb holder pops out, you find a LED flashlight close to the same diameter, and either turn a spacer sleeve or turn down the OD of the flashlight down a bit to be snug slip fit. The only trick is to get the LED module the same distance into the stand as the original filament. Also try to have a bit of air circulation between the LED and the first diffusing lens -- should be cooler than a tungsten bulb but there's still heat to be dispensed with.

Get a flashlight with a high / low setting. Don't get a UV flashlight. Do consider adding a photo neutral density filter to your arsenal and maybe a UV cut off filter if you're doing extended viewing (some flashlight LEDS go into the near UV -- best if you know the LED maker and check on line for specs (e.g. Cree xxxx) .

In the Zeiss Standard case, my recollection is that I got three decent LED flashlights for around $30 total. One of the others went into a Nikon or Leitz - don't recall right now. My recommendation is to get a flashlight with a rechargeable Li ion 18650 battery; since they last a pretty much a whole viewing session and can be recharged hundreds of times.

The whole thing should cost less than a replacement bulb, you'll have a cooler power supply, a bulb that should last a lifetime, and no cords or external power supplies to mess with.

[Kalleboy]

Any guides to build one ?
(at part time job so not much time for DIY learning jobs)
- I'm familiar with Asian flashlights and such 18650 batteries...(I own 10s of them )
- I used to have access to expensive CNC-machines back in adult nightschool years which ended few years ago. Made cool items: like accurate machine vises, versatile DIY wood lathe(like Unimat swiss-style) and RC-car bodies,...Pheww...
Someone asks 355€ (400 usd$) for a simple Laboval 2 LED conversion:
http://www.bw-optik.de/led-mikroskopbel ... ed-bausatz

- When I have time I buy either 1.) a new bulb base module(for a modern halogen) or 2.) LED.

[billbillt]

I also find LED lighting viable and simple to implement... Low heat, low cost, and a life of thousands of hours are a deciding factor...

BillT