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Hi Wim Will attempt the disassembly of the DEC tonight. I watched the video till 11:50 where he removed the whole DEC axis A few questions. 1- At the start, do I need to remove the plate covering the belt drives and motors and remove the belts? 2- Do I need to remove the encoder cables on BOTH DEC & RA since I am only touching the DEC? What do I need to watch out for? I will be devastated if I damage anything. I’m quite handy with DIY, but still terrified. On reassembly, IF I FIND THE PROBLEM AND FIX IT, is it simply a reverse order of putting everything back? WHAT WILL I NEED TO WATCH OUT FOR? Thanks.

Thanks Wim I will try that. @AstroKeith @MikeP I have indeed taken the mount off the tripod, turned it upside down, and shook it vigourously, but no loose sounds at all. The only sound I hear is the small handle of the grub screw that fixes the CW shaft, as it moves up and down freely when I turn the mount upside down.

Thanks Wim. What should I do now? The mount is abroad, so sending it to FLO is not an option. What’s the safest approach I can take without risking damaging anything? I am worried about stripping the mount myself.

Thanks Keith what do you mean by the polar scopes top orifice? do you mean the opening on the front of the mount’s body? that’s an IOptron iPolar camera. I did remove it, as I used the opening to insert the endoscope to look inside the mount body. I also used my little finger and palpated all round the inside of the hole. The adapter that is fixed to the mount is not catching or touching anything other that the edges of the hole itself.

Yes, indeed, I undid the two small thumb screws on the DEC setting circle and it rotates freely! Im losing my mind here!! I think I am missing something VERY OBVIOUS and SIMPLE!! There’s this loud audible knock as you mentioned! There must be something VERY LARGE AND SIMPLE that is blocking the DEC axis’ rotation!!! What am I missing….

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?

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?

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.

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

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

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

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

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.

@wimvb Help please!

Good morning Wim PLEASE help me if possible on the thread I started regarding a stuck DEC axis. I have imaged SEVERAL TARGETS over at least THREE months following adjusting the backlash, with excellent results. The WO Star 71 has been on the mount for about a year with ZERO issues. Yesterday, I put the Esprit 100ED on the mount, and obviously had to RE-BALANCE. The DEC is stuck? The mount and WO scope was stored safely in a warm room for 4 weeks while I was away on travel. My last imaging session was 22nd November, and everything was working perfectly?! NO ONE TOUCHED THE MOUNT WHILE I WAS AWAY?

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.

Anybody? Please.

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

Ok, so I removed the focuser and decided to start from scratch. I can confirm that the 4 couplers provided by ZWO with the EAF are not precisely machined, as some of them are rough on the outside AND inside, and on looking at the inside and between the gaps there are some aluminium fillings here and there. I have 4 EAFs in their boxes, so I had a total of 15 couplers to look at. (1 is fixed to the WO Star 71 and working perfectly well) The first time around, I had used the coupler with the LARGEST hole to fit the Esprit's focuser shaft. On further inspection, I think that was a little loose. The THIRD size is the correct one, but needs to be smoothed on the inside. On trying different couplers from the 4 boxes I had, I believe the THIRD size is the correct one to use, but I needed to use a 2mm allen key to smooth the inside of it and flatten a lot of aluminium fillings. Now the tricky part. The LARGEST coupler size I had installed on the EAF last week would not come off the focuser's shaft!! Even after completely removing both grub screws. It was STUCK, and I could only remove it after some clockwise and anticlockwise rotation, which was not a good thing for the motor inside, obviously. On inspection, the EAF's arm shows deep grooves. Not sure why that happened. Also, the coupler I removed showed friction and rub marks on the outside. Anyways, Reinstalled the EAF using the Takahashi bracket, M4 35mm bolts, and used the size THREE coupler after cleaning up the inside. I first made sure that when the coupler was fixed inside the housing, before installing the EAF, when I manually rotated the coarse focuser knob, everything rotated very smoothly. Now works very smoothly, NO BEEPS, and Backlash is at 190-200. I believe when I forcefully removed the coupler off the motor's shaft, the motor developed some more backlash. Zero is set at 0.5cm, and total travel is about 16500 steps, rough focus point of 6cm is at about 12000 steps.

The telescope is brand new. I do not think it’s the Esprit’s problem that the ZWO’s couplers diameter is a tight fit in the focusers housing.

Yes, the coupler does indeed rub on the inside of the housing. Before even installing the actual EAF motor, when I turn the COARSE knob manually, there is obvious resistance and a grinding sound. Not sure how to sort this. The only thing I can think of is using a file and trying to decrease the actual diameter of the coupler by a millimetre or so. With regards to attaching the coupler without it being inside the housing, I do not think that is possible. The focuser’s shaft is deep inside the housing.

Yes, exactly. The coupler on my esprit is a very tight fit in the focuser housing, same as the picture above.

I feel that the coupler is a tight fit inside the Esprit’s housing where the coarse knob was.

The coupler feels rough on the outside. Where there are gaps for flexibility, the edges of the coupler are not well machined and there are tiny protruding edges.

Yes, it certainly felt stiff. I used the 4th coupler with the biggest hole, but it felt stiff. I have no other options to use. It’s the only coupler that fits. Should I sand it down a little?