Help please! Dec axis stuck!

[oymd]

Good evening everyone. 

I had my AZ-EQ6 Pro tucked away safely under a cover for the past month while I was abroad on work. 
 

It had my WO Star 71 on it, along with all the accessories, camera, EAF etc. 

It was working perfectly fine till the 25th of November when I travelled. I imaged the Rosette over 5 nights and there were no issues whatsoever. 
 

Today was the first time I’ve touched the mount and scope. 
 

I replaced the WO Star 71 with the Esprit 100ED. 

Obviously I had to REBALANCE RA and DEC. 

Tamale WO Star 71 had been on the scope for the past 6 months, and I never had to rebalance since I initially set it up. 
 

RA balanced fine, and I had to add an extra counter weight. 
 

On trying to balance DEC, it seems to be jammed. The clutch releases fine, but I cannot move Dec beyond a few degrees. There seems to be a KNOCK in either direction?

What’s going on?

I connected the mount in NINA, and very carefully slewed at lowest speed. RA is fine, but DEC slews just a few degrees and stops. 
 

NO GRINDING SOUNDS OR ANYTHING, just stops. 
 

I did not touch the scope since last successfully imaging session?

The only two things I can remember:

1- to improve guiding and backlash, I was advised to run guiding assistant in PHD2 a couple of months ago, and did the 1/2 turn thing on the front and back grub screws on the DEC housing. 
 

2- on looking at some historical pictures of my setup, the puck’s/saddler’s locking screws used to be on the west side of the mount. Now they are on the east? Not sure how that happened. 
 

Anyways, I do not want to damage or force anything on the mount. 
 

How should I trouble shoot this? I noticed while looking in through the port where my iPolar sits that the shaft for the CW bar is not properly aligned with the polar scope’s opening?

many thanks. 

 

IMG_9587.MOV

Edited January 4, 2022 by oymd

[oymd]

Anybody? Please. 

[MikeP]

Hi,

It is hard to understand how a mount that was functioning perfectly can suddenly lock up when left alone for a few weeks. 

I have the same mount (older model) and I got fed up of mine being "sticky" in both axes when left for a short time.  Nothing like your video - just a bit of light pressure to get things moving.  I finally broke down and dismantled the mount and regreased by following this video https://www.youtube.com/watch?v=21wRVsNU6_w   It really is quite simple to do and the DEC axis is the first part to be worked on.  Unless someone more experienced comes along who can offer better advice, I'd suggest following the first part of the video - it will let you see what is going on inside..

You say that you adjusted the DEC backlash screws a couple of months ago and the last imaging you did was of the Rosette.  Just to be clear, was that imaging done after the DEC grub screws were adjusted?   The diagrams in the following that show how the adjustment screws work are helpful since it is a bit counter-intuitive https://www.astro-baby.com/EQ6 rebuild guide/EQ6 worm alignment.htm  

Sorry I can't help more.

Mike

PS If you do follow the video, be very careful unplugging the encoders, they are quite delicate.  That said, I have encoders turned off because they are said to interfere with guiding.

[oymd]

31 minutes ago, MikeP said:

Hi,

It is hard to understand how a mount that was functioning perfectly can suddenly lock up when left alone for a few weeks. 

I have the same mount (older model) and I got fed up of mine being "sticky" in both axes when left for a short time.  Nothing like your video - just a bit of light pressure to get things moving.  I finally broke down and dismantled the mount and regreased by following this video https://www.youtube.com/watch?v=21wRVsNU6_w   It really is quite simple to do and the DEC axis is the first part to be worked on.  Unless someone more experienced comes along who can offer better advice, I'd suggest following the first part of the video - it will let you see what is going on inside..

You say that you adjusted the DEC backlash screws a couple of months ago and the last imaging you did was of the Rosette.  Just to be clear, was that imaging done after the DEC grub screws were adjusted?   The diagrams in the following that show how the adjustment screws work are helpful since it is a bit counter-intuitive https://www.astro-baby.com/EQ6 rebuild guide/EQ6 worm alignment.htm  

Sorry I can't help more.

Mike

PS If you do follow the video, be very careful unplugging the encoders, they are quite delicate.  That said, I have encoders turned off because they are said to interfere with guiding.

Thank you for your reply.

Yes, indeed, AFTER fine tuning the backlash about 2 months ago, I imaged at least 4-5 targets over at least 20 nights, with NO ISSUES.

The only reason I tried to manually move the DEC axis yesterday was to balance the Esprit on the mount.

The Star 71 had been sitting on the mount balanced for the past year or so, and never needed balancing.

 

[oymd]

@wimvb

Help please!

 

[AstroKeith]

Maybe cold temperature has made the change. You adjusted out the backlash when it was warmer. Now its cold the various parts of the mount will contract at different rates. The housing is aluminium which changes a lot.

[oymd]

All these targets were taken AFTER fine tuning the backlash on the DEC axis.

Mount has been working fine. Never touched for 4 weeks until I attempted to balance the Esprit yesterday.

 

 

[oymd]

1 hour ago, AstroKeith said:

Maybe cold temperature has made the change. You adjusted out the backlash when it was warmer. Now its cold the various parts of the mount will contract at different rates. The housing is aluminium which changes a lot.

Do you suggest I undo the FOUR allen bolts on the dec housing a little?

[oymd]

1 hour ago, AstroKeith said:

Maybe cold temperature has made the change. You adjusted out the backlash when it was warmer. Now its cold the various parts of the mount will contract at different rates. The housing is aluminium which changes a lot.

Do you suggest I undo the FOUR allen bolts on the dec housing a little?

[AstroKeith]

7 minutes ago, oymd said:

Do you suggest I undo the FOUR allen bolts on the dec housing a little?

I dont have an EQ6 so cant advise on that specifically. It does look like a strip down in at least part is inevitable  though.

[ONIKKINEN]

Dont have that model of mount, but in my experience with another equatorial mount adjusting the worm is something that has to be done quite frequently if the temperature and/or humidity changes a lot. It has happened to me also, i adjusted backlash on RA to be as good as it can be, tested that nothing binds and then several sessions and a couple months later it no longer slews at all due to binding. Your case does sound a bit different though since you cannot even move it with the clutch open.

I would try to adjust the clutch, since you said there is a knocking sound on both ends it means something is binding that shouldn't bind. No idea how to adjust the clutch in the AZEQ6 though, since its different from other clutches, but maybe someone who owns the mount can help you there.

[wimvb]

I've been speed reading this thread. As others have suggested, cold may have to do with it. Since the axis is stuck mechanically, I wouldn't try to force anything with the motors, so leave the power turned off until you know more.

Second, take everything off the mount while testing. It will be easier to tinker, and you don't want to release bolts with an expensive scope hanging off the mount.

[wimvb]

From here on there are two possible ways to go. 1 is to release bolts and screws in the DEC mechanism. 2 is to warm everything up with a heat blanket (a car seat heating cover runs off 12 V and could keep your mount warm). If moisture has come into the mechanism and has frozen, then heating and drying is needed. With the weather we have had lately, with fog and temperatures slightly above freezing alternated with really cold weather, moisture is definitely a possibility. Although I don't know how it could get deep enough inside the mount.

The thing I would is nr 1. Try is to release the four bolts that hold the worm housing just a little (a quarter turn). Are they tightened more than when you adjusted backlash? Does the DEC axis move more freely. If not, release both backlash grub screws a little (not more than a quarter turn should be necessary). By now the DEC axis should be loose. Move the DEC axis to verify that it can swing freely. Once the axis is loose, tighten the grub screws to the point where they both push equally against the worm mechanism. Then tighten the four bolts that fix the housing. Don't use too much force. This procedure should have released any tension that had possibly built up in cold weather.

 

[Tomatobro]

I just watched a you tube strip down of this mount and its hard to see what would allow the free movement and stop your video shows. One thing that struck me watching it was if something had dropped into the hole in the shaft ( used for the polar alignment) then that would give the characteristics shown in the video

[wimvb]

@Tomatobro Excellent idea and easy to check.

[wimvb]

I watched the video again, and you do have an iPolar or similar device. Is there a chance a part of this has come loose and dropped into the hole in the CW bar?

[oymd]

Thanks for your helpful replies.

The mount was abroad in warm temperatures above 20C, stored safely inside the house under a cover.

The last imaging session was 22nd November, and temps were about 20C outside.

Now temps outside are about 17C, so I do not think its a cold thing.

The youtube video I did shows some sort of KNOCK when I move the dec axis either side.

NO ONE touched the mount since I imaged on the 22nd of November.

Very strange

[oymd]

2 minutes ago, wimvb said:

I watched the video again, and you do have an iPolar or similar device. Is there a chance a part of this has come loose and dropped into the hole in the CW bar?

I do not think so, but I have an endoscope at work. I will have a look inside the mount this evening

[wimvb]

Just now, oymd said:

The last imaging session was 22nd November, and temps were about 20C outside.

Now temps outside are about 17C, so I do not think its a cold thing.

Then temperature swings can be ruled out. But do remove the polar camera and have a look inside the housing.

[oymd]

3 hours ago, wimvb said:

Then temperature swings can be ruled out. But do remove the polar camera and have a look inside the housing.

I have spent the past hour trying everything:

1- Had a very good loom inside the mount with the endoscope. Everything is PRISTINE, and nothing is loose inside the mount.

2- Undid the 2 grub screws and the four allen keys on the DEC housing. I introduced significant backlash on the DEC but again within the limited few degrees of rotation available.

3- Removed the saddle and again inspected everything from above, went down the CW housing and looked either side through the polar scope windows, NOTHING.

BTW, the CW shaft windows are perpendicular and not inline with the polar scope's view.

Basically, nothing I do changes the fact that the dec axis is kind of HARD LOCKED.

[wimvb]

That is very unexpected. The "knock" you descibe suggests a mechanical obstruction and not just binding (binding is more gradual, like tightening a nut). So you need to find out where that obstruction is. Worst case you may need to take out the DEC axis. But start with loosening one item at a time. Is there a sound in the DEC housing when you rotate the mount in RA? An item in the housing would probably move, and you might hear that.

It's difficult to analyse and suggest things to look for without being with the mount.

[oymd]

31 minutes ago, wimvb said:

That is very unexpected. The "knock" you descibe suggests a mechanical obstruction and not just binding (binding is more gradual, like tightening a nut). So you need to find out where that obstruction is. Worst case you may need to take out the DEC axis. But start with loosening one item at a time. Is there a sound in the DEC housing when you rotate the mount in RA? An item in the housing would probably move, and you might hear that.

It's difficult to analyse and suggest things to look for without being with the mount.

I’m starting to think that there maybe some kind of issue with the DEC clutch?

Can I check something I’ve noticed?

When I release the Dec clutch, and then rotate the saddle a few degrees before I reach the knock on either end, should the clutch be rotating as well?

It seems the clutch rotates with the Dec axis?

Is that normal?

With regards to the RA, it rotates freely with no sounds. Even when I powered on yesterday briefly, RA moved perfectly. 
 

By the way, is it safe to rotate the RA a full 360 degrees?

Edited January 5, 2022 by oymd

[oymd]

41 minutes ago, wimvb said:

That is very unexpected. The "knock" you descibe suggests a mechanical obstruction and not just binding (binding is more gradual, like tightening a nut). So you need to find out where that obstruction is. Worst case you may need to take out the DEC axis. But start with loosening one item at a time. Is there a sound in the DEC housing when you rotate the mount in RA? An item in the housing would probably move, and you might hear that.

It's difficult to analyse and suggest things to look for without being with the mount.

Wim, here’s what I meant by the whole clutch moving with the Dec axis. 
 

Is this normal? I’m not sure. I thought when you release the clutch, the Dec rotates freely, but the actual clutch should stay fixed?

 

[wimvb]

1 hour ago, oymd said:

reach the knock on either end, should the clutch be rotating as well?

It seems the clutch rotates with the Dec axis?

Is that normal?

That is normal. I checked earlier this evening. Clutch and cw bar rotatw with DEC

[wimvb]

Does the DEC setting circle move freely when you unlock it? It looks to me as if there is something blocking free movement in DEC, just as Tomatobro suggested.