Celestron AVX very stiff in DEC

[Droogie 2001]

I have had my Celestron AVX mount for about a year and tonight I went out to collimate my 8 SE as I had not properly done this for a long time.

Anyway after mounting everything and checking the balancing I noticed that the DEC axis was difficult to turn by hand (no power at this time)

Checked and adjusted the counter weight and tighten shaft tried again and it got worse. Took off OTA and checked everything.

Basically if I tighten the counter weight shaft as I have done for the last year it becomes stiff. If I add a counter weight it gets worse. So much so that it becomes hard to turn by hand. I can also see the counter weight shaft slipping when I rotate the DEC on occasions too. This should not be happening.

I am not sure what has happened. I took the mount out a week ago and it performed fine (though with a different OTA)

I know the AVX's are known to be a bit stiff in both axis especially when new but this is not correct. As I say power can be ruled out as I am not even using power at this time.

Its probably just out of warranty   so if there is anything I can do myself then I am willing to have a look if it is not too intrusive or complex.

Any help would be much appreciated.

[andrew63]

Can't help with advice, but i think Celestron products have a 2 years warranty - so i wound get in touch with your supplier.  Hope you get it sorted.

andrew

[mattyk-usa]

What is the position of the Dec Clutch when you are doing this?  

When you say "counterweight shaft slipping", in what manner?   I cannot picture any movement of the counterweight shaft itself.

If someone were noting unusual stiction in the Dec axis on this mount in the absence of the other symptoms you have described, I would have first suggested checking the gears and worm for clearance, corrosion, or perhaps grease separation.  I'd still suggest this in your case, in the event that the other symptoms you're seeing are unrelated.  One possible thing to check also is the Dec axis shaft - the AVX typically has a very small amount of play about the Dec shaft, is that still there? Corrosion there could cause additional stiction when adding a counterweight.

Certainly the AVX should have no issues with the C8.  I assume you have not added significant weight elements beyond perhaps a 2" diagonal and EP?

Bet of luck sorting this out - very strange symptoms you've described there. 

[Droogie 2001]

Thanks for the suggestions. If I remove the DEC clutch it becomes stiff when I add the counter balance shaft (whether the weight is attached or not) . It seems to be inside the mechanism.

No corrosion is visible. No noticeable play in the DEC shaft.

The Celestron's do appear to have a 2 year warranty so looks like I will be going done this route.

[mattyk-usa]

Yes, I was suggesting that you inspect the interior.  Any corrosion of the shaft or binding between gears and worm would have to be internal, to produce the symptoms you described.  

Being that the mount is under warranty and that you personally are not familiar with the mount's internals, I would also recommend allowing Celestron to sort things out.  If Celestron service in Europe is anything like it is in the States, that resolution will unfortunately take some time - however, the general consensus here has been that the results are invariably a better performing mount.   Again, good luck and clear skies.  

[Droogie 2001]

It appears I may have found the reason though it is odd and I cannot quite understand why or what has changed. If I unscrew the plastic/metal "cup" from the counter balance arm and then attach the arm with counter weights the DEC axis is fine. It seems as though the "cup" is affecting the rotation in DEC.

Sent from my iPhone using Tapatalk

[Droogie 2001]

Press sent in error! Anyway Celestron should be sending me a replacement part to resolve issue. As I say it's odd because the part does not look damaged or broken and I have not done anything different. I guess I won't know until I get new part and compare it but at least the main mount head is ok and not faulty.

Sent from my iPhone using Tapatalk