Last updated: 14 April 2009
Subject: ETX-125 RA drive stops Sent: Monday, April 13, 2009 07:15:29 From: Nohr Tillman (email@example.com) I have read as much as I can on Mike's site and wanted one last opinion from the experts. I have my ETX-125 (circa 2000-2001) apart for various binding issues. Unintended consequences - the RA drive motor screws I tightened up pushed into the stop ring, causing binding and further gear pop. Fix is straighforward, but the reassembly I want to get right. Looking at the black stop ring (in the pic) it looks like it wants to straddle the post in the base. In other words the main "V" should be placed around the base post to hold it in place and prevent it from rotation. However, in this position, it would yield less than 360 fork rotation. If installed away from the base post, the stop ring could rotate and the fork could rotate somewhere less that 720 degrees stop to stop. Main question is: by design, should the black ring straddle the base post, and not rotate freely (looks like how th part was designed) or not straddle the base post and rotate as it is pushed by the upper fork plate? Thanks for your time, Nohr Tillman Troy, MI, USA, Earth
From: P. Clay Sherrod (firstname.lastname@example.org) The ring must be mounted so that the telescope will rotate 720 degrees and then hit either of the stops before rotating further. Its only purpose is to keep the base wires from pulling too far along the trail of motion. Put the ring down in such a way that the two extended segments will HIT the small protruding peg of aluminum that you see in the left part of this photo, coming from the metal plate. That is the stop peg. Dr. Clay _____ Arkansas Sky Observatories MPC H45 - Petit Jean Mountain South MPC H41 - Petit Jean Mountain MPC H43 - Conway West http://www.arksky.org/
Yes, Thanks Dr. Clay! Instructions understood! Now, I just have to shave down the drive screw that is pressing that ring upward and binding up the base and fork assembly. This is the reason I'm in there in the first place. Nohr Tillman Troy, MI, USA, Earth
Best of success on this.... Be sure and be very careful when reassembling; the wires going through the central axle are very easily twisted and broken. Dr. Clay
Thanks again. Utmost care is being taken, and some things (like the base/battery cover) have been removed entirely until the mechanicals are tuned up. Fortunately (or not) I've got the patience, touch and tools to get into and out of this clean, so far anyway. Hate to bother you, but one other thing you might help with: the loose rear cell syndrome. I do hang my camera back there, and the cell is just loose enough it make the camera just off-center of the view. It's not falling out, nor is it threaded on. My version is shouldered on the outside, pushed into the rear assembly, then through a metal ring and the tube part swedged against that ring. Red locktite didn't set up in the joint. I managed to wick it out though. Was gonna gently tap on the flange to re-set the swedge. Any other luck with those? Nohr TillmanI suggest using Gorilla Glue and carefully follow the instructions....there is no other way to secure it. Dr. Clay
Go back to the Tech Tips page.
Go back to the ETX Home Page.