First, make sure the area is clean and dust free. Then, remove the eyepiece from the eyetube.
Flip the eyepiece upside down and locate the mounting ring that will be removed. The ring may appear a different color of metal as shown in the photo.
On the ring, there will be two notches that are opposite each other.
You will need a tool like a jewelers screwdriver that will fit well into the slot and not damage the ring or eyepiece body.
The reticle retaining ring screws into the eyepiece with a fine pitch thread.
With your tool, unscrew the ring by rotating it counter-clockwise or to the left as shown in the photo.
Be careful not to scratch any of the surfaces inside your eyepiece.
Also be careful not to introduce dirt or dust into your eyepiece during this procedure,
Next, carefully remove the ring from the eyepiece.
Resist the temptation of using your can of compressed air.
Oftentimes the mist that comes from cans of compressed air leaves a white film that is VERY hard to remove.
A very small paint brush or a small very fine dusting brush used in cosmetics is a good choice.
Next, you are ready to drop in your eyepiece micrometer.
If you can tell which side of the glass has the image etched on it, that side faces into the microscope.
If you cannot, the markings on your reticle may be out of focus which means the reticle is installed backwards. You will need to remove the reticle and flip it around the opposite way.
With the reticle in place, it's time to return the threaded ring.
Again be careful not to introduce dirt or dust into your eyepiece.You may need to clean and start over again if too much debris is present.
Rotate the ring in a clockwise motion until the ring is snug with the reticle.
Do not overtighten.
Check if the reticle is tight by shaking the eyepiece and detecting no rattle.
With your reticle installed, it's time to check your work.
Put the eyepiece to your eye and point it to a light source overhead.
You should see the pattern clearly.
If not, slide the eyepiece into the microscope and make a basic setup.
If the reticle is still out of focus, you may have the reticle installed backwards. If flipping the reticle does not work, contact Meiji or your local dealer for assistance.