Celestron 8se mount issues

[oscar_camilleri]

Hi 

Im wondering if anyone has experienced this before and knows how to fix it. 

As of yesterday, my mount started experiencing issues with what I understand is the alt negative motor or gear ( up key on the HC). Its running at full slew speed  irrespective of what slew rate i select. 

For example if i choose slew rate 5 , all of the other directions work fine, but when i press the the up key , it just goes at full speed ahead.  I also noticed that its affecting the tracking as a result.  As soon as it tries to make a correction it just slews way off target.  

I did some research and the advice seems to be that it could be a loose clutch, but want to make sure before i go and start opening things. 

[Cosmic Geoff]

You can easily diagnose a loose clutch. The clutch is what prevents the tube moving freely in altitude. Just try moving the OTA up and down while the outfit is indoors. There should be moderate resistance.  The OTA should be positioned fully forward in the clamp.

[oscar_camilleri]

Not sure, there is the usual resistance when I try t manually move the OTA and the issue also persist when i remove the OTA from the mount. 

I have updated the HC and control board to the latest revisions.  As i said its weird that all other directs work fine and at the appropriate slew rate, but when i press up, it just goes at the maximum slew rate , irrespective of what slew rate I'm currently on. 

[oscar_camilleri]

might have found the issue. It appears that the mounts digital encoder might have gone bad.  Just checked the get RA-Dec settings and when i'm moving the alt negative nothing is registering.  Ohh well , lets raise a ticket with celestron. 

[Cosmic Geoff]

A couple of nights ago I had an odd issue with my C8 SE. In the middle of a GoTo, the tube descended rapidly downwards, losing the alignment, but after re-starting the mount I was able to carry on with the session. It's not clear whether an electrical glitch caused the problem but the vertical clutch did feel rather loose in the downward direction.

I subsequently tightened the clutch as follows: Behind the handset storage recess is a small cover which can be removed by undoing 3 Philips screws to reveal a large nut.  Give the nut (size approx 1 3/16" ) a tweak of a few degrees clockwise with a suitable spanner.