I was fiddling with my Etx 90, with the focus knob off. I was turning the shaft of the focus knob when it suddenly withdrew into the inside of the OTA housing. Something must be loose inside. Can I take out the bolts or screws in the back of the OTA and fix this problem without destroying the scope?
Problem with Etx 90. Can I disassemble?
Posted 27 January 2020 - 02:46 PM
Yes, it's quite easy. Just be gentle on some of the plastic parts.
Posted 28 January 2020 - 05:00 PM
You've run it too far forward. If you point the corrector down the mirror will slide, hopefully, to the end of its travel. Then you will have to go fish. Note the thread at the point where the shaft passes through the back plate.
If it's inside the scope you will have to remove the back plate. it threads into the tube.
Edited by Geo., 28 January 2020 - 05:01 PM.