Into the Abyss...MGZ40 Rebuild.....

[ChrisPCook]

OK guys, I've received the sight, and have already taken a small looksie...
Here's what I am facing.....
1) Need correct screws on top housing....May also need to clean up the threads in the existing housing...
2) Small chipped area, easy repair....
3) Figure out what is missing or installed 180 so I get a "right side up" image....
4) Try to clean her up a little and give her some TLC

Obviously step 3 will be hardest, any help that can be given for those that know these scopes or German optics will be appreciated, also if anyone notices anything out of kilter internally let me know. Although few have taken these apart. Chris.....

[ChrisPCook]

First step was to get the top assembly off, easy to do as it had non original screws that were lightly threaded in, there were 3 screws to remove. The spirit level bubbles are easy to remove if needed.
After removing the screws I carefully lifted the top off, nothing fell out, everything in place, I then went on to removing the top back cover plate and the prism up top, there is a retaining plate with a spring clip anchoring in the prism. There were also two small shims (Old thin bakelite? I'm not for sure) on each side of the prism, I placed them back as found, but am not sure if this is correct, but I replaced as is. Obviously changing the orientation of the prism does not change the image, i.e. flipping 180 still results in the same image. This is it for now, it may be a week, possibly sooner before I revisit this, I've got lots of projects going. But, enjoy the first look into a MGZ sight for most of us. Chris....

[ChrisPCook]

One more photo tonight....I used a jewelers screwdriver, but even then I had to throw it up on the grinder for some thinning to get it to fit tight and snug....anyways, side view of the interior top retaining plate....

[ChrisPCook]

On the 2nd post I mentioned the I had three screws to remove on MY scope to get the top assembly off, there is a fourth screw to be found under the rear spirit level bubble corner. Chris....

[DARIVS ARCHITECTVS]

It's hard to remember how my MGZ40 came apart, so it's hard to help out with diagnosing why yours had an inverted image, so I'll have to take mine apart and add the pictures to this thread later this week. I suspect there's a lens missing in yours, hence the flipped image.

[DARIVS ARCHITECTVS]

***** This post has been edited by 42rocker in order to restore the photos. *****

I figured your problem out! You are missing the entire upper prism assembly! Good luck trying to locate a replacement though. Here is a step by step disassembly of the upper half of the MGZ40. Pay close attention. First, obtain the correct size screwdriver or you'll damage the screw heads. When reassembling, DO NOT overtighten the screws or you WILL strip out he fine threads.

Okay... Let's start the surgery...

First, remove the four screws holding the four corners of the top periscope assembly on. One of the screws is accessed from underneath.

Now, you see the bottom of the upper periscope that you removed. There is a small triangular, mirrored prism inside which receives the image from the front lens and directs it downward. As you take the lenses and prisms out, clean the film off the glass surfaces with a Q-tip and distilled alcohol. This will remove the chemical film of 60 years and make your scope crystal clear.

Looking at the main assembly, you see the upper main prism which receives the image from it's top, slanted surface.

Lift the top prism assembly out and look at it. Here is the top...

.. and here is the bottom. The image travels straight through this prism. The end surfaces are angled so as not to create reflections or glare.

Now inside the main body of the scope and you will see a lens held in place with an outer ring. I found this ring loose when I first got my scope and had to carefully tighten it.

Carefully use a tool to engage the slot in the outer ring and remove it, turning it counterclockwise. carefully drop out the lens and retaining ring. Here are the parts.

Here is the lens assembly, with an inner aluminum ring around it which I have not figured out the purpose for yet.

Now, the lower prism is deep inside, and rotates with the lower eye scope. It's fuzzy in this picture. This lower prism redirects the image from top to horizontal, toward the eyepiece. The lower prism assembly may be removed by doing the following steps. First remove the retaining ring.

Turn the scope over, and loosen the two locking screws on the sides of the pivoting eyepiece, then remove the retaining cover and gasket by removing the bottom two screws. When installed, this cover prevents you from lifting the lower prism upward and removing it. Now, I stopped at this point, but it appears that you push the bottom prism assembly upwards through the scope body to remove it. At the point I reassembled my MGZ40 since there was no need to clean the lower prism or eyepiece lens surfaces.

That's as far as I got. The rest of the MGZ40 should not be disassembled unless there is great need to replace parts or the altitude adjusting mechanism is damaged or needs fresh grease to allow it to move easier. Any time you disassembly these 65 year old optics, you risk damaging the screws, so they are better off left alone.

Good Luck!

***** Above post was from DA and photos restored by 42rocker *****

[ChrisPCook]

DA-Thank you for taking the time to disassemble your sight in order to help me out, I appreciate you doing that for me! I now know what I need, so now begins the next part of the "hunt." This won't be impossible to locate, just $$$ I'm afraid. Thanks again, Chris..

I also will need to go into the side of my MGZ and regrease and clean up the elevation gears, when I do that I'll be sure to add more photos. Thanks, Chris..

[ChrisPCook]

A year later, and I'm still looking for the long prism and base for inside...I missed one on epay awhile back, got the 2nd high bid, but that counts for nothing on epay.

I did find an interesting website and link detailing the scope, also a lot of other MG items here as well:
http://mg34mg42.forumactif.net/optique- ... 0-t399.htm

Chris....

[DARIVS ARCHITECTVS]

Link doesn't work unless you join that French forum.... Could you PDF the web page and upload it here?

[ChrisPCook]

Here you go, sorry for the delay, translated over from the French....

Autopsy MGZ40

Message PM Tues, July 7 - 19:36
I decided to open the belly of my MGZ40
to see how it looks. cyclops
Here the side door, nothing to report. It's full of emptiness.

Here is the bishop rotating in its housing.

The then becomes lodged or the bishop. Basically we perceive the lens
Arrival of the scope.

Details bishop removed. It contains two lenses that allow to make a
angle of 90 degrees to the image.

The upper part of the MGZ40 two bubble levels and small cap rotation
contains the first image capturing prism.

Detail elements present in the rotary cover.
The prism has one side coated mirror image that retains all
its intensitée. A moçeau of black cardstock comes to putting on this face
The small metal piece used to hold the lens in place.
The inside of the hood and Locking are phosphatic.

Then the pics....

[ChrisPCook]

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[ChrisPCook]

final...until the day I get mine finished....

[www.Prussia.us]

Man alive Chris, how many irons do you have in the fire

[Bil]

He needs a big fire-it gets cold up there! ---bil

[ChrisPCook]

My little campfire has became a conflagration (there's my 50 cent word for the day)....I won't even get into the Flakfernrohr 10x80 project, or the SF14 project, or the SA Brens, or the......well, you get the idea... Chris...

[ChrisPCook]

After two years I just bought all the parts I need to complete this project, got a complete assembly (w/o base) out of Germany for a great price!!! Chris... After I get it together I'll show it off....

[DARIVS ARCHITECTVS]

WOOHOO !