It’s so interesting to disassemble a telescope especially those have a very precise and big gears. I’ve disassembled my computer since I was 8 and 8 years later I disassembled my LX90. I will tell you how to do so step-by-step. However, take it at your own risk, I will not responsible for any damage done to the telescope. I suggest that you read all the procedures before you do anything. If possible, read one more before you start and it’s advisable to print this article with you or leave your monitor on when you are doing your work.
In the Part I, I’m going to tell you how to disassemble the corrector plate. The photos below are clickable for a larger version.
(1) First, unscrew every screw on the black housing in front of the OTA. There are 4 on the top and 3 at the bottom. The screws have to be unscrewed by Allen Wrench. I have 3 from Meade when I bought the scope.
(2) Afterthat, you have to remove the screws on the ring which have the specification of the telescope. Please make sure that you don’t point your scope down at this moment just in case the corrector plate fall down and result in severe damage.
(3) Caution! Although you have all the screws undone, don’t remove the corrector plate now or you will regret for life.
(4) Now, check whether the Meade engineer made a marking over the edge of the corrector plate and the black housing. If he did, continue to the next step. If not, you have to do your own marking. Make sure that it’s visible!
(5) Do you see 6 pieces of cork slices filled in the gap between the corrector plate and the housing? I suggest removing them before you proceed to remove the corrector plate. After removing them, hold your hand on the secondary mirror (the center obstruction) and turn the scope down. If the corrector plate doesn’t fall down at this moment, try the way below.
(6) You suppose to see 2 big gaps, don’t you? I used a knife which was small enough to fit into the gap and insert it to the maximum (the knife holder may touch the corrector plate now). Use the way that you open a tin with a spoon to remove the corrector plate. I heard a loud “boom” when I successfully remove it. Do you still have the secondary mirror mounted on the corrector plate? You better have it untouched because once it’s removed, you can’t put it back precisely. You have to call UPS and pickup the item back to Meade. Haha… Frankly speaking, I did remove it accidentally. Luckily, I made a marking on the screws that hold the secondary mirror. Luck really plays an important role. I was able to put it back almost the same as before.
(7) Okay, the corrector plate is removed. What shall I do next? I did cleaning of the corrector plate and removing of a toothpick which was ACCIDENTALLY dropped into the OTA via the baffle tube.
(8) Let me show you the back of the corrector plate which faces the primary mirror.
(9) No more, I am going to put the corrector plate back now. I restore the cork slices first. Wish you a happy removing! 
While trying to culminate my 8” LX90 one of the screws became unscrewed from the secondary mirror. I was unable to start the screw and tried to loosen the other two screws.
Long story short all three screws became unscrewed and the secondary mirror fell off.
I have remove the ring and corrector plate replaced the three washers over the center pin and replaced the three screws and reattached the secondary to the corrector plate.
I am now having difficulty collimating the scope. Have I gone beyond the point of no return? Do you think I can resolve culmination or do I need to send the corrector plate with the secondary mirror to Mead?
Thank You for you input.
Leo Gruenke
P.S. This all happened before I read you article
I believe that you’re still able to get the secondary mirror back near to the original position. This job will be time consuming though.
I assume that yours is the same with mine (old secondary design (3 screws)).
1. Unscrew secondary mirror from the holder.
2. Revolve the secondary mirror by a few steps.
3. Screw it back and do the collimation. See whether you can bring it back.
4. Repeat steps 1 to 3 until you get a perfect collimation.
P/S: Try to screw each screw equally when doing the collimation as it is supposed like this. Don’t overscrew again.