Zeiss 3 D rangefinder . The GREAT OEM 2

[globbitz]

Hello Steve_M,

OK, that's a real shame about your shipping crate.

I've checked my bulbs, and the ones in the holders are frosted, and the two loose spares are clear glass. Both of the loose bulbs are marked as 6V and 0.05A.

They are familiar to some vehicle instrument lighting bulbs that I've seen in the past, so I would imagine that you would need to find some automotive bulbs that are rated similarly.

Unfortunately I've discovered that all of my bulbs in holders are glued-in as well as secured by small grub-screws, so I can't remove any bulbs from holders to double-check the rating, but they must be the same as the loose bulbs - only frosted. Hopefully your faulty bulb(s) can be removed easily.

Please see attached photos - perhaps someone more familiar with automotive instrument lighting will identify a familiar fitting and post details.



NOTE: The photos are taken against 8mm ruled notepaper.

Regards,
Paul

[Steve_M]

Thank you. The pictures help a lot.

I just did some searching for this type of bulb and came up with nothing. I do have an extra holder, so just the bulb is all I need. Maybe someone has an idea where to get these.

[globbitz]

Hi Steve,

Well, if all else fails, then you could try searching on eBay for this description:

'10x 6v Bulb Lamp Bi-Pin 55mA Meter Instrument Ref 673BP'

...and find out dimensions etc from the seller or the manufacturer VCH, as you might be able to make the bulb (ref. 673 BP) above work with a little-bit of hacking. The glass envelope of the original is approx 3.2mm diameter by my rekoning.

Regards,
Paul

[Steve_M]

Well, I have located some original bulbs and they are on the way. The person also suggests that mag lite bulbs may work, so I will try those. Also, I am hardly an expert on the OEM-2, but thought I might as well try and write a short explainer of its use. Please feel free to let me know what is wrong and what I am missing. As I read it now, this document is quite rough still.

For instance, I have no idea what the lever and illumination on the upper left , on the left side is supposed to do. Any ideas? Also, This document looks a lot better with formatting and I also inserted pictures in my document to show each knob, lever, switch, lens, etc.

____________________________________________


The Carl Zeiss Jena OEM-2 is an optical rangefinder which works by stereoscopic principle with moveable sights. OEM-2 is the abbreviation for "Optisches Entfernungs Messgeraet Nº2". It served with the Artillery-observers of the army of the former communistic German Democratic Republic, NVA (Nationale Volks Armee). It reflects the latest development of stereoscopic rangefinders made by Carl Zeiss in Jena. A characteristic of this construction is the biaxial sightkollimator, which makes the sight staying adjusted in cases of athmospheric influences like air rising off pavement, which may cause changes of the angle of the mirrors or prisms.
The OEM-2 was made from 1969 to 1976.
It was made for
- Artillery observation
- determination of linear and polar coordinates of targets or hits.
- determination of range and horizontal and vertical angles.
Notice: The artilleristic circle of eastern army systems is devided by 6000 units (1/6000
"Mil-Strich") instead of 1/6400 like it is used in NATO countries. There is no compatibility.
In normal use it was mounted on a strong tripod out of the vehicle.
The objectives are 45mm and the power is 14x. The range is 400m to 15,00m. The error is 3.8m when you are really good J

Set up of the OEM-2

The OEM-2 is actually quite easy to use.
1. Set up the tripod. Make sure it is level. Note that 2 of the legs have geared grips that act as adjustment for micro fine adjustment. You can adjust the tripod for height. I like to keep it low so I don’t have to lift the OEM-2 as high to place it on the tripod. After setup, you can slowly adjust each leg to a comfortable height. This tripod is an amazing piece of engineering.
2. Open the doors on your case. In the upper left hand corner is a battery pack. Unscrew the middle screw to open the battery pack and place 4D batteries in the case in the configuration indicated. Your case may also have another power supply in the lower left corner for use with 220V AC or 24V/12V DC. I like to use just 4 D batteries. After filling the case with batteries, drop it in the center hole of the tripod. Note the notch for proper placement. Make sure the switch is set to “white” (off). This thing eats batteries quickly.
3. Your case should also contain a small white cable. It is easily recognizable as one end has a female two prong plug and the other end is an 8 pin plug that fits into the battery box. Plug it into the battery box. You will need to slowly thread it on. Make sure it is fully locked down.
4. You are now going to lift the OEM-2 onto the tripod. It only goes on one way. Note the 4 notch black knob. Make sure it is fully disengaged-counterclockwise. The OEM-2 is lifted up and slid into place in front of this knob. The back plates hold it on. Once the OEM-2 in on the tripod, push it all the way to the back and then tighten the black knob. As you can see, the knob rises up and locks the OEM-2 in place.
5. There is a little flip door on the OEM-2 near the bottom. Rotate the OEM-2 so that door is right above the black knob. Open the door and plug the other end coming out of the battery box into the OEM-2.
6. The moment of truth-flip the switch on the battery box to “red”=ON. Next turn the big knob right below the right eyepiece to KR. You should see illumination in the X and Y windows. When you flip the switch over to MK, you should see illumination in the center azimuth lens (window) and the left altitude lens (window). If one of two are lit, but not another, you may need a new bulb. If none are lit, you need to check your power supply to make sure power is reaching the OEM-2. I found mine needed some adjustment to the wiring in order to work properly. The bulbs are removed by unscrewing the black round cylinders found all over the OEM-2. If all fails after work, your OEM-2 is still useable during the day and as a fine pair of 3D binoculars.
7. Make sure the lens covers on the top front of the OEM-2 are closed. Now flip the switch that say Beleuchtung (illumination). Look though the binocular eyepieces and you should see some triangles and a distance scale. If not, either a power issue or bulb again.
Pendel, MI/W, Mr/N, and E-Skala all adjust the brightness of the reticles in the views discussed below. Blende switches the reticles on/off. Weitwetzel places a targeting reticle in view. Steckdose powers up the external power source on the upper left of the unit.

Use of the OEM-2

1. First off, this unit are amazing binoculars if nothing else. Make sure the covers are flipped up on the front of the lenses at the top of the OEM-2. After they are flipped up, you can lower the polarizing filters if the glare is too bright. These filters also work well to help see the reticles as discussed later. Use the large black circular handles to rotate the OEM-2 either back and forth (azimuth, lower left front of unit)) or up and down (altitude, left side of unit)). Notice the disks in front of these handles. They will either tighten or loosen the tension. Point the OEM-2 at something far away. Remove the caps on the binocular eyepieces. Place the metal covers over the eyepieces. Look through the eyepiece and adjust the focus using the small black knob on the side of each eyepiece. Make sure the lever above the right eyepiece is flipped to “white”-Off. Pretty cool!
2. On the right hand of the OEM-2 we can see the buttons to zero the display of the mechanical X-Y-coordinate calculator. It counts the "hm" (hundred meter). The little black knob inbetween is the socket for the illumination lamp. Any movement of the OEM (turns, variation of sights or changes of vertical angle) will automatically be registered by the calculator´s gear. You can also hold them down and turn them to reset to “0”. The lens in the center is to see the horizontal angle in military angle units 1/6000. Notice you can also turn the large green gears at the bottom of the OEM-2 to reset the calibration.
3. Above the right ocular there is a dark round UV-filter for infrared-reconnaissance. It can be switched on by using the little lever to the right of the ocular. It is an infrared-sensitive screen, which shows a pale brown light if it is hit by IR-rays of the spectral area military IR-devices use. You can easily test it with your TV-remote control.
4. Let’s try to use it. Point the OEM-2 at something far away during the day time. Open the optical windos on the front top of the OEM-2
5. Make sure the polarizing filters are in place. Those little windows are illuminating all the reticles inside the unit. Look through the binoculars eyepieces are focus the unit. You should also see the distance scale and a set of reticles forming several triangles. Pick out something definite in the distance to focus on. Could be the corner of a chimney, the tip of an antenna, a letter on a billboard, something stable and small.
6. Now the fun part. Think back to your high school days of trigonometry. If we know the distance between such as the binocular objectives, and the angle it akes the point the right binocular lens at an object, we then can know the distance from the left lens to the object (basically the same as the right lens as long distance). When you look through the binocular eyepieces, you should see a set of triangle reticles in each one. Close your right eye and picture the reticles on the left eye against the background of the scene. Now switch eyes quickly. Back and forth. You will see that the reticles appear to your brain as though they are not aligned in each eye. There is separation. This is the view in one eye, the triangles and the distance measure
7. Rotate this knob. You will see the scale in the eyepiece view go up or down. It is measuring meters distance.
8. Magically, the triangles will appear to get closer as the distance measurement get s closer. It gets harder and harder to differentiate whether there is separation from the right eye view to the left eye view. Finally, you will get to a place where you can’t see a difference. BUT, your eyes are fooling you. Once you get close, your brain starts to adjust the view for you. They appear lined up, but they are not. This button here vibrates the triangles in each eyepiece view. It shakes them to trick your mind into seeing that final little amount of separation. Adjust the big knob (distance adjustment) until the triangles in the left eye line up perfectly with those in the right.
9. Finally, the “shake” can be adjusted. It is called pendula. The knob in the square can be adjusted from 1 to 6. 1 gives a very small vibration and 6 large. When you are all done, you have the distance in the reticle, the azimuth on the center window and the altitude on the left window.
10. For nighttime use, the same thing with the optical windows closed and the illumination on.

The rest of the knobs are all self-explanatory. Just flip, turn, adjust them and you will figure it all out.

[globbitz]

Hi Steve,

Yes, I did think of the maglite bulbs myself, but thought that they might be too bright especially as they're jolly bright even at 3V (for the 2 x AA battery Maglite version that I have) when compared against the 6v of the OEM-2's supply. Certainly worth trying if all else fails.

I have a feeling that the control on the Upper-Left-Hand side allows the Graticule to be changed, but I don't recall whether that was for the wide-angle view, or the normal view. Give it a try, and see whether that's the control for the Grid-Square graticule?

Regards,
Paul

[zeissasembi]

OEM 2 was developed from 1966 to 1976 I think

Production - 1976 - 1989/90

batterybox - 4x 1,5 V D alkaline + 1x dummy or 5x 1,2 V rechargable D cell

[nonfood]

rangefinder oem 2 for sale

OEM 2 was developed from 1966 to 1976 I think

Production - 1976 - 1989/90

batterybox - 4x 1,5 V D alkaline + 1x dummy or 5x 1,2 V rechargable D cell

I offer potential customers for Sale rangefinder carl zeiss oem 2 former Czechoslovak army rangefinders are completely unused to email price nonfod@gmail.com

[zeissasembi]

The OEM 2 is a great unit. Its in use every week