Prism realignment for LOMO binocular scope

zzffnn · Post by **zzffnn** » Tue Apr 14, 2015 5:19 pm

Thank you for checking this post. Please kindly comment here:

I have a LOMO Biolam binocular (AU-12 head) scope whose left prism (for left eyepiece) needs realignment. The prism is held tightly in its current position by 2 or more screws (I did not see glue there).

As it is, the left eyepiece produce light reflections. I can also visually see that the left prism is leaning further to the left side than where it should be (I can see part of the central tube). Damping left eye tube with Blutak reduced light reflection, but could not eliminate it. Changing eyepiece did not help (as expected).

Right eyepiece/prism/tube is perfectly fine.

My questions are:
1) should I ask my local microscope tech/dealer to realign the prism, or should I do it myself? I am decent with DIY work and has re-blade'd a condenser's diaphragm before, though I had to left out 2 damaged blades (could not put them back in - need one more hand).

2) is there high risk of damage or harm if I realign the prism myself?

3) For a microscope tech, this should be an easy and cheap work, I assume ?

4) or is it better to just buy a binocular head? I don't see one currently available though. What is a fair price for an AU-12 bino? A monocular head costs around $40 shipped. I bought my LOMO scope for $110 shipped.

Thank you again and have a great day!

Charles Krebs · Post by **Charles Krebs** » Tue Apr 14, 2015 5:33 pm

Check out this PDF. Could be helpful.
( especially check page 19, Photo 8 )

https://ia902700.us.archive.org/30/item ... mation.pdf

zzffnn · Post by **zzffnn** » Tue Apr 14, 2015 6:48 pm

Thank you very much Charles.

It seems to be an easy work with the right tools. Disection of my LOMO bino head is even shown in page 17 (actual page# is page 19 figure 8 as you said).

Unfortunately, I do not have centring slide or eyepiece with cross-line graticule and my LOMO Biolam has no field diaphragm (blink test may not work using field diaphragm).

Maybe I can do blink test on a hand-drown cross line? Or do you have a better DIY method?

Edit: maybe buy a cheap $8 hemocytometer and move its cross lines towards edge of right eyepiece, then align the left prism by looking through left eyepiece (while remembering cross position from the right eyepiece)?

zzffnn · Post by **zzffnn** » Thu Apr 16, 2015 12:06 pm

Well I got rid of the light reflection.

Adjusting the 3 screws holding the eyepiece tube (shown in page 17 photo 8 of the file that Charles kindly cited) did not remove reflection. But that file pushed me the dissect and investigate further.

What removed my light reflection was:
slackening the two screws highlighted in red circle in my photo then setting the prism vertically. The screw highlighted in red triangle (the other screw not shown in photo) set the prism horizontally, but I did not change those.

Another thing to note is that eyes (at least mine) are not very good at detecting light reflections, while camera is far better at that.