Trying to solve slewing issue CPC800

[Chris]

3 hours ago, Cosmic Geoff said:

I just found this thread while looking for a CPC800 stripdown guide.  I have been having a slight problem with the azimuth drive on my CPC800. I started a thread about it a while ago.

Now I have followed the directions above - slacken the azimuth clutch and spin the mount to see if it moves freely.   I find that it does not spin freely - there is some resistance and I can hear and feel a periodic clunking, which no doubt is associated with the change of note I can hear when slewing under power.

At least I have some idea what the problem is now.  Next step is to strip it down and see what horror lurks within. Maybe the plastic bearing balls.

I take it it's not under Celestrons 2 year warranty then? Let us know how you get on! 

[Cosmic Geoff]

I am the 3rd owner, and the previous owner said nothing about a warranty.

Before dismantling, I noted that so far as I could see there was clearance for the fork assembly to spin on the fixed base, if the latter was placed on a flat surface with the AZ clutch loose.  But it wouldn't.

I dismantled the assembly following the Nexstarsite pdf. When I got as far as loosening the big nut by a fraction of a turn, I tried the rotation and found that it now moved freely. I continued dismantling and found the specified number of nylon balls, looking clean and lubricated with a light grease.   So I reassembled everything, leaving the big nut slack enough so that the base would spin a little way under its own inertia - I tightened it and then backed it off by about 1/6 turn.  No evident play.

I didn't renew the Loctite, figuring that these parts seemed stiff enough not to undo themselves anytime soon.

With the cover on, I connected handset and power, giving it a spin at max speed.  It sounds better - will have to see how it performs when imaging.

[Chris]

Result! So it was just that the big nut was a little over tight then. I'm sure it will be fine now, but I wish you all the best for when you get it out under the stars.