#1  
Old 22-10-2017, 01:35 PM
Lognic04's Avatar
Lognic04 (Logan)
Registered User

Lognic04 is offline
 
Join Date: Mar 2016
Location: Melbourne, VIC
Posts: 889
Dec very hard to move?

Hi all ,
I have noticed that my CGEM's DEC axis is very hard to move - you need to apply about 2 kg of force to get it to move. It definitely isn't binding, i adjusted the gears so that it wouldn't, but the strange thing is, in PHD to move dec it needs about 10-15 pulses, it seems like there is still backlash?
I'm thinking that this is stiction caused by the awful grease and/or the ring gear needing to be polished.
Reply With Quote
  #2  
Old 22-10-2017, 02:24 PM
Atmos's Avatar
Atmos (Colin)
Ultimate Noob

Atmos is offline
 
Join Date: Aug 2011
Location: Melbourne
Posts: 6,980
Is it hard to move while the mount clutches are disengaged?
Reply With Quote
  #3  
Old 22-10-2017, 02:40 PM
Lognic04's Avatar
Lognic04 (Logan)
Registered User

Lognic04 is offline
 
Join Date: Mar 2016
Location: Melbourne, VIC
Posts: 889
yes.
Reply With Quote
  #4  
Old 22-10-2017, 02:45 PM
multiweb's Avatar
multiweb (Marc)
ze frogginator

multiweb is offline
 
Join Date: Oct 2007
Location: Sydney
Posts: 22,060
Sounds like bearings might be binding?
Reply With Quote
  #5  
Old 22-10-2017, 03:06 PM
glend (Glen)
Registered User

glend is offline
 
Join Date: Jun 2013
Location: Lake Macquarie
Posts: 7,033
Back off rhe lock nut on the bearing until you can detect play then just snug it ip.
Reply With Quote
  #6  
Old 22-10-2017, 03:31 PM
Lognic04's Avatar
Lognic04 (Logan)
Registered User

Lognic04 is offline
 
Join Date: Mar 2016
Location: Melbourne, VIC
Posts: 889
Quote:
Originally Posted by multiweb View Post
Sounds like bearings might be binding?
How would i check that?
Reply With Quote
  #7  
Old 22-10-2017, 07:36 PM
multiweb's Avatar
multiweb (Marc)
ze frogginator

multiweb is offline
 
Join Date: Oct 2007
Location: Sydney
Posts: 22,060
Quote:
Originally Posted by Lognic04 View Post
How would i check that?
Remove the RA and DEC shafts and check them for scaring. Then make sure the bearings are free and clean and regrease them. I do that to my mount every year.
Reply With Quote
  #8  
Old 22-10-2017, 08:04 PM
casstony
Registered User

casstony is offline
 
Join Date: Feb 2006
Location: Warragul, Vic
Posts: 4,493
Quote:
Originally Posted by glend View Post
Back off rhe lock nut on the bearing until you can detect play then just snug it ip.
Try this for a start, it may be all that's needed.
Reply With Quote
  #9  
Old 22-10-2017, 08:59 PM
ChrisV's Avatar
ChrisV (Chris)
Registered User

ChrisV is offline
 
Join Date: Aug 2015
Location: Sydney
Posts: 1,737
Even take the lock bolt off.
Also, it could be clagged inside - mine was fairly tight when I got it new at the end of last year. I pulled it apart and re-greased, and it was a lot better.
Another possibility. Could also be that the shaft is bolted on too tightly. Take off the counter-weight-shaft and check down there?
Reply With Quote
  #10  
Old 22-10-2017, 09:15 PM
Lognic04's Avatar
Lognic04 (Logan)
Registered User

Lognic04 is offline
 
Join Date: Mar 2016
Location: Melbourne, VIC
Posts: 889
Yeah, I think my mount needs a good regrease. Is it a good idea to get new bearings too or are they not really needed?
Reply With Quote
  #11  
Old 22-10-2017, 11:21 PM
ChrisV's Avatar
ChrisV (Chris)
Registered User

ChrisV is offline
 
Join Date: Aug 2015
Location: Sydney
Posts: 1,737
I wouldn't bother about things like that yet. Just slowly pull apart and have a look/see. Photograph everything as you go, and watch where each washer was. You need a big bench. You should see pretty quickly what's causing it to be so stuck - if lucky its just the clutch bolt. Try not to force anything. If you get stuck put up photos.

I was lucky I had a CG5 to practice on before I attacked my CGEM
Reply With Quote
  #12  
Old 22-10-2017, 11:23 PM
ChrisV's Avatar
ChrisV (Chris)
Registered User

ChrisV is offline
 
Join Date: Aug 2015
Location: Sydney
Posts: 1,737
Quote:
Originally Posted by multiweb View Post
Remove the RA and DEC shafts and check them for scaring. Then make sure the bearings are free and clean and regrease them. I do that to my mount every year.
I'm starting to think that might be a good idea - a yearly grease etc
Reply With Quote
  #13  
Old 23-10-2017, 06:42 AM
Lognic04's Avatar
Lognic04 (Logan)
Registered User

Lognic04 is offline
 
Join Date: Mar 2016
Location: Melbourne, VIC
Posts: 889
Which lock nut/bearing are you referring to Glen and Chris?
Reply With Quote
  #14  
Old 24-10-2017, 01:23 PM
ChrisV's Avatar
ChrisV (Chris)
Registered User

ChrisV is offline
 
Join Date: Aug 2015
Location: Sydney
Posts: 1,737
I meant to loosen this clutch knob first and see if it moves OK. If that's tight then its something to do with the shaft and bearings. The whole shaft comes off fairly easily so you can have a looksee. If its out of warranty and you don't mind having a go I can PM how I did it.

If its not that then its probably the worm gear and ring gear (I think that's hat its called) - you said you had loosened the worm gear so there's backlash so its not binding as you say.
Attached Thumbnails
Click for full-size image (20170601_203933 copy.jpg)
168.7 KB25 views
Reply With Quote
  #15  
Old 24-10-2017, 07:35 PM
Shiraz's Avatar
Shiraz (Ray)
Registered User

Shiraz is offline
 
Join Date: Apr 2010
Location: ardrossan south australia
Posts: 4,918
Hi Logan - suggest that you try Glen's idea first. I backed off the bearing preload on my (similar) NEQ6 when the dec got too hard to move freely and it worked fine thereafter.

I don't have the mount in question, but think that the nut shown in the very first part of this video is the one to loosen a little bit (after backing off the locking screws as shown) and then gently tighten it back up to the point where side play is gone, but the axis still rotates freely. https://www.youtube.com/watch?v=Cp3Vq_6G5bg The video doesn't show how to get the end cap off to get at the nut, but hopefully that shouldn't be too difficult.

Last edited by Shiraz; 24-10-2017 at 07:58 PM.
Reply With Quote
Reply

Bookmarks

Thread Tools
Rate This Thread
Rate This Thread:

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump


All times are GMT +10. The time is now 12:53 AM.

Powered by vBulletin Version 3.8.7 | Copyright ©2000 - 2024, Jelsoft Enterprises Ltd.
Advertisement
Testar
Advertisement
Bintel
Advertisement