EQ6 dec wobble

[robulaic]

I have the NEQ6 mount - for a while now I've had a wobble on my dec axis. Even when the clutch is locked I get a cm or 2 of free movement. It's very annoying since it changes the position of the scope, which makes aligning that much harder. Does anyone have any suggestions on what this could be?

[bojan]

Backlash in worm gear?
Or grab screws on dovetail flange adapter are loose.

[whzzz28]

Worm gear backlash/issue.

I had the same thing on me HEQ5 on both RA/dec after a few months of use. But not 2cm worth, enough to cause issues though.

Tighten the worm gear (a little bit) and it will go away. Just don't over tighten it or you will get stricture or, even worse, binding (your motors will make a horrible grinding sound).

I know this is only for the HEQ5 but i cant find one for the EQ6, but i suspect it is similar;
http://www.sky-tron.com/heq5-rebuild/heq5-we1.htm
The screws are probably in different positions but you should be able to tell which is which.
Follow the advice listed on the page;
- Run RA/dec through a full cycle to make sure there is no binding. If there is binding, loosen what you have done (a little, and i mean a very small amount).
- Make sure you can turn the gears with your fingers. If you can barely turn them or require a lot of force to turn them then it is just a little too tight, losen it a bit.

Also, remember that due to gear designs there will always be a little bit of backlash so don't try and get it super tight or binding will occur.

Good luck!

[bojan]

It could also be that worm axle bearings are loose - so before you go and adjust the meshing, as suggested by Nathan, you need to tighten the retaining ring (under black (?) cover, with 2 small holes).
http://www.astro-baby.com/EQ6%20rebuild%20guide/EQ6%20Strip%20Down%20Home.htm
http://www.astro-baby.com/EQ6%20rebuild%20guide/EQ6%20declination%20rebuild.htm

[robulaic]

Thanks for the replies, I've tightened the worm gears like whzzz suggested and that didn't help. I will have to look at what bojan suggested.

Cheers
Rob

[deanm]

Good to see Bojan still trying to save EQ mounts from unneccessary surgery!

Well done!

Dean

[bojan]

I feel their pain, poor creatures.. :P

[robulaic]

I've tried both those suggestions and can't seem to get rid of that wobble.

[bojan]

There must be a reason for this.
Could you provide some photos?
like: wobble left, wobble right.
Then image of work shaft (based on huge amount of shift, I still think this one is moving inside bearings, or even together with bearings). Did you observe what is actually moving?
Try this: move the dec axis with one hand, and place the finger on those parts I mentioned (worm axle).. you will easily detect the unwanted movement with your finger tips.

The important thing is to determine what is happening, before you start dismantling the mount blindly.. it is very easy to damage something.
And if you can't determine what is wrong (mind you, this mechanism is actually very simple), it is better to ask for help from someone who has some experience with those mounts.
Try to study the suggested websites carefully and try to understand the mechanical details of the design - the reason for your problem will become obvious once you know how the mount works...
If I were closer, I would love to help you with this.. but I am in Melbourne and in next couple of days I will be even further away..

[davewaldo]

Hi all,

I just thought I'd post to say thanks for the info in this thread. I've now managed to fix about one degree of free movement in my eq6 dec axis.

I had to adjust the mesh, and it took a bit of fiddling to get right, to start with it seemed to do nothing so its worth persevering with!

Thanks again

Dave.

[Astro_Bot]

Hi all,

I just followed the Astro Baby guide (Step 5) for adjusting worm/worm carrier position and successfully removed freeplay in my RA axis. It's a quite straightforward procedure: 10-15 minutes for the adjustment, being careful, then an hour or so to thoroughly test RA operation afterwards - no binding or grinding detected at all. Everything worked beautifully and now I have no discernable backlash/freeplay in either axis. The mount operates more quietly now, too.

I highly recommend the procedure if you have any noticeable freeplay.

I was generally happy with the mount before, but now I'm very happy. :)

[Osirisra]

Hmm time to do mine me thinks...

[ZeroID]

Me too I suspect. Found some funny wee wiggles in my star trails ...