Setting The Backlash on your CGX or CGX L Mount
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- เผยแพร่เมื่อ 22 เม.ย. 2021
- Today's video is all about your backlash and how to get it just right on your Celestron CGX or CGX-L. Word of warning: If you are still in warranty, doing this will void it! The process is very simple and will require a 2 and 3 mm Allen wrench. Be very careful removing the 4 SMALL screws that hold the cover in place. Lose those and it will be hard finding replacements. As always, if you have any questions... you know where I live! Thanks for watching.
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Thanks Jeff - This has been my goto reference for the last few years to correct RA and DEC backlash on my CGX mount.
Glad it helped...
Great video! Even after reading the manual for the CGX, I was still kind of confused about how to do this and what to exactly look for, and your video provided enough details to answer any questions I may have had as well as remove any apprehension of me performing this adjustment. Thanks again for sharing this!
Fantastic! I have backlash and didn't know how to correct it. Your video is exactly what I was looking for. Thank you.
Glad you found it useful and now you can fix up your backlash...
All done. I found play between the gears and very little to no movement with the body. After backing off the larger screw until I had no backlash I found I had 1mm play return to the body. A test run powered up proved no binding or loud gear noise.. if anything it sounds better. Excited for my next session! Thanks again for the down to earth instructions.@@jeffrh
@@saskgrass Excellant, glad everything worked out. If you are to tight for some reason. Just back off on that 3 mm allen. I found that in assembly from the factory they didn't use anything like blue Loctite and my screws would back out over time. Just keep an eye on things. I only need to set the backlash in the spring before starting my season. This has been good enough for a full season of use. Enjoy your new found guiding bliss... ;-)
Great Video! Thank you very much for this helpful Guide.
Thank you Jeff, excellent video.
From the factory my assembly had so much travel, the motor would hit on the housing. The other one was so tight it had no movement at all. The setup from the factory on these mounts is absolute garbage. I've had nothing but problems with mine since I got it, but was so new to the hobby I thought it was me or I would've returned it.
Now that it is Winter down here, I have been watching piles of these videos and working on the mount. So many owners having issues with new mounts.
Did you manage to fix / improve your mount?
@@HollomanUFOLanding not really... The grinding noise has gone since performing several "adjuistments" (that Celestron didn't bother doing properly), like this, and also trying to move the motor and gear pulleys up and down the shafts so the belts align and don't half hang off the pulleys.... But I still have accuracy issues, and the annoying thing of clicking the mouse on the slew control and occasionally nothing moving for a full second and then finally moving. I probably have more slop somewhere but I've tried everything I can find.
Excellent Video Jeff - Thanks! So easy to do. I can't wait to see the improvement in star shape after I adjusted the screws. I have had the mount 6-7 years and never made an adjustment. The sloppiness became more evident when I stared doing Astrophotography. The Dec motor assembly had minimal backlash and the motor housing about 3mm play. The RA Motor assembly had significant motor housing motion of 4-5 mm while also moving the counter balance bar which increased the backlash on the worm gear. The PHD2 Guider showed my last calibration set:
RA Rate 15.227 A-S/Sec
25.397 PX/Sec
Dec Rate 8.907 A-S/Sec
14.856 PX/Sec
My stars at 1:1 show some ellipse shape my FWHMx vs FWHMy is about 3 pixels off from round.
Also be careful putting the plastic cover back on because the small foot of the other plastic housing must fit over the other foot otherwise it doesn't close down easily and gives the appearance it is binding on the motor assembly when it isn't.
Jayson, when you try this. You want to just take the backlash out and not go past that point. You can over tighten and this will bind the worm against the larger gear. Not enough room for the worm to float. I do both my CGX and CGX-L before I start my season in the spring. I get wonderful guiding and using predictive pec in PHD2 and multi-star keep the RMS error under .5 for the CGX and .7 for the CGX-L. Another thing that helps to set the backlash is to move whatever axis you are working while making the adjustments. This helps you know when the backlash is gone. Clear skies...
Thanks so much for making this video! Great work!
Hope it helps...
Nice video. Appreciate you posting this. I have made this adjustment for my CGX quite a few times. I actually replaced that 3mm "bolt" with one that is about 5mm longer because there was very little thread left on it and it would often back itself out and be lying in the plastic case. I was surprised it worked but I did it on both axes and no problem.
Would like to see a video of your re-grease exercise if you ever get a notion!
Thanks, R Fortner, That might have to wait till next spring when I give both mounts a tune up! Will not be opening the RA or DEC cases again till then unless something weird happens, but who know... Stranger things have happened.
@@jeffrh I would also appreciate this, both axis are very very stiff ( from day 1 )
@@doccortex1203 If the mount is still under warrenty. Call Celestron to see what they say first. Doing this yourself will void the warrenty. If the mount is out of warrenty and your not afraid to try this... It's not that hard and with a couple of allens and a phillps head screw driver. You are on your way. Good luck...
Nice Video. Many thanks for this your Rezension.. I have the CGX-L and have too much game.
Glad it helped!
i have the exact same problem on my CGX, RA , huge backlash , and i mean huge , probably 1/4 inch or more at the tend of the counter weight bar.
And if i got this right all i have to do is back off ( counter clock) on the tensioner screw and bring the 1 mm back with the Set screw !!!!
I've been waiting a year to get to this cause i was terrified . i think that's why the guy sold it . its a great mount , ive seen nights of 0.38 RMS with my C8 Edge HD loaded if I'm East heavy ( counter weights ) and guiding towards the East ( M27) but ... forget North East , like Wizard Ned or the bubble Neb, IC 1805 or any other ..
gonna try tonight to get this going. i will not over tighten, i like a bit of backlash.... just a tad.
Hi Mitch, Long tiime since we last talked... What you are trying to do is preload the worm just a little bit. Like an 1/8 turn. with the 3 mm allen head wrench. That should take all the backlash out of the system. Then you take that 2 mm allen head and limit the travel the whole housing can move up and down. You don't want it so that there is no motion as that will bind the worm on the bigger gear. With a couple of mm's of travel. This will allow the worm to float on that big gear as it rotates and if there is a high spot on that big gear. The 2 mm will let it ride up that high spot and then come back down. Hope this helps... If it doesn't let me know and I'll try again... ;-)
Hey Jeff, That did it , wow, amazing guiding last night... PHD was reporting 0.31/ 0.48 RMS all night, and that huge RA jump on the graph is gone. You are the best. I will link a PHD screen shot later...
@@BrokenPik Glad things worked out... If you do the backlash every spring along with a regrease of that bigger gear. You'll have great guiding for many years! Great to hear from you again... One more tip for your guiding pleasure! Get the Dev Build of PHD2 and enable Multi-Star Guiding. You'll get even better RMS numbers...
here it is , the link to... PHD2 www.flickr.com/photos/astrodude-mitch/51251627593/in/dateposted-public/
Hi Jeff, great clear demo and instructions on this issue, thanks.I have a cgx that is around 2years old. It has always had some slop in RA only. After watching your video I finally had the confidence to have a go at a fix. What I found was when the plastic cover was removed, the slop almost disappeared ( just the smallest of play). A fair conclusion would be that the plastic cover when screwed on pushes on the housing/worm gear lifting it off the main gear creating the slop. So if the housing is brought forward using the 3mm bolt the condition would I guess worsen . Has this been an issue for you? Or has anyone else had this issue. Any suggestions on a fix would be gold , cheers Martin
Thanks, MartinI have a CGX-L and CGX. My mounts didn't exhibit what your describing. You want to make sure that the wiring for the motor isn't under the housing when you put the cover on. If you look at the video again. you will see that my wires are off to the side and when I put the cover on. They stay to that side and do not go between the cover and the housing. What might be happening here... is when the cover is tightened. If the wires are under the housing. They will push the housing up which will make your backlash worse. You can try this for yourself... With the cover off. Move the mount axis your working on side to side and then push the housing up. You should notice that the backlash will get worse with the push and go back to zero when you let off. I think you may have those wire in the wrong spot and they are pushing the hosuing up which will change the backlash... Hope this helps...
Thanks for your reply Jeff, all the wires are to the side except the small white one. When the cover is fully removed, the slop decreases by more than half. I have noticed some slightly protruding plastic on the 3 mould filling holes on the backside of the cover, which line up with high point of the motor. I might get the dremel and remove the high plastic and 1mm more around where the white wire comes out of the centre of motor( plastic cover is 3mm thick). At the moment I don’t have the cover screwed hard up and there is only a very small amount of slop. I might leave it at that for now, and track the slop variation over the upcoming hot Australian summer when I might get some expansion.
@@martinalcock680 You might try taking a picture of the cover to show where those problem areas are and send them to whom ever you pruchased the mount from... That sure doesn't seem right and you might try sending the image to Celestron. You never know? The other axis seems to be fine? Have you taken the cover off that axis to try it out to see if you get the slop? If you don't, you know it's that cover and you can talk intelligently about the problem to someone... A couple of pictures to the right place can do wonders... If the other axis is DEC and it works on the RA. I would leave it there and try to get the cover working the best you can on the DEC axis. That isn't as important as the RA axis and if your have good polar alignmnet. The RA is all that should be getting pulses when you guide if you do... Hope this helps...
About ready to upgrade this mount after crap guiding. I think I understand what you are doing. How about the belt tension? Look forward to testing this out.
SubOrbitBen, Thanks... My belts were still good for tension. You dont' want them to tight as I don't like to much strain being put on the worn gear bearing and the DC servor motor bearing. If you can move the belt in the center up & down around an 1/8th to a 1/4 of an inch. You should be in good shape. These belts will stretch if over tighten them. Most of the backlash is in the worm mesh. If you go tighter with the belt... Just remember you will put added stress on the Worm and Moter bearings. I just don't think it's worth it and I'm getting great guiding RMS numbers with the small belt movement I stated above...
@@jeffrh This video only adjusts the Dec but is all of this valid for the RA as well?
@@Ben_Stewart Yes, same thing applies to both RA and DEC. I showed RA because it was easier to show in a video...
Hi, the first video of this process I have seen which actually makes sense. Seems like this adjustment is required for this mount from time to time even though Celestron doesn't want people making the adjustment. I have seen this issue come up a few times.
Do you need to back off the 2mm adjustment screw before making the backlash adjustment? Also, when you remove the grease, do you just mechanically remove it, or do you use solvents?
Thanks Kevin, Both of my mounts are out of warrenty and I'm only sending them back if I think I can't fix it myself. If your finding that your backlash is moving after you set it. I might put a drop of Blue Loctite on the 3 & 2 mm allen threads. I found that mine would back out from usage because they were too loose. I think Celestron was finding that some people were trying to set the backlash and they didn't quite know what they were doing. As a result, some individuals were over tightening the 2 mm allen which resulted in binding of the gears. When you have the backlash set correctly. If you move the housing while moving the axis in question at the same time. You will feel the backlash open and close up with the housing move. This is the float that I was talking about. If things are correctly set. You should feel the backlash and you will not jump teeth. If you are jumping teeth. You have the 2 mm too loose. With about 2 mm of housing movement. You will be golden. That's plenty of room for the worm to float up and down on the big gear.
I do not use any solvents to clean of the old grease. I use a tooth pick to remove the grease that has gone to ether side of the worm and big gear teeth. kind of tedious but works for me. When if finished removing the old grease. i'll use SuperLube and another tooth pick to apply a thin coat on the big gear only. When that's done, I'll move the axis from lock to lock to work the new grease in. Hope this helps...
@@jeffrh Thanks for the response... It does help. I've had the CGX 2 years now... but guiding is getting worse. At least now I have something to check and if backlash and the tension are ok, I can at least clean and reapply the grease.
Hi Jeff, Thanks for another great and useful video. I have the CGX (out of warranty) and have been having an issue here lately. Any comments would be appreciated. I will try to brief but informative. I'm guiding (PHD2 multi-star) and getting decent performance i.e. round stars usable subs. DEC does well showing fairly flat lined with a few small bumps and shallow waves but again round stars. The RA does fair but can be somewhat wavy. Did I mention I’m getting round stars? Then seemingly out of nowhere the DEC jumps for just a brief moment making a ^ then quickly settles back down and guides as before. In NINA I just stop imaging for a moment and restart. Not fun when it happens near the end of sub. 😞 If I let it complete the image, that image will have a small faint ghost star very near the actual star image. Any suggestions would be appreciated. Clear skies and new moons!
You didn't say how old your mount was? When the CGX first came out. They shipped with over tightened worm bearings. That could be what you are seeing... That would show up as a bind in one area that repeats. You can look at the PHD2 logs with a tool that is on their website here. openphdguiding.org/phd2-log-viewer/
You need to check and see if you have any backlash. Grab the counterweight bar and see if you can move it back and forth. If there is some play when you are doing this. You have backlash that needs to be taken out. A gust of wind could move the scope just enough to cause those faint trails you are seeing. By taking the backlash out of the system. Wind can still be a problem but not as big of one. Another thing that might cause what you are seeing would be a netural balance. You need to have some preload with the counterweights to one side and this will help to keep the worm gear in contact with the larger ring gear. Good luck and I hope these tips help you out...
@@jeffrh Thank you for your quick reply. Sounds like I should follow the steps in this video on both motors. The mount was purchased in October 2020. No way to know how long it had been sitting on the shelf. Narrowing it down per your comments: no wind, RA is always east heavy even after flip. However, perhaps I should try adjusting the DEC to be a little more camera side heavy. I am considering going a head and replacing the grease while I am at it. Sounds like a cloudy night sort of thing to do. LOL
I will take a look at the logs. Perhaps I can find a video about interpreting the same.
Thank you again Jeff! I really enjoy your videos and appreciate your style of teaching; always easy to follow with clear instructions.
Jeff you did the RA gear/worm assembly...same approach for declination gear/worm?
Dan, Yes...
thank you for a fresh look at how to adjust the backlash. One question I have pretty basic: Is the only test for backlash like how you demonstrated, play in the dec unit, a few mm in either direction? We do not want any play?
Nicholas, Correct! You don't want any play between the worm and the bigger gear. If you have the backlash adjusted correctly. You will have a small amount of preload using the 3 mm Allen-head on the housing to keep the worm always in contact with the bigger gear. The small 2 mm limits how much travel the housing has up & down. That keeps the worm from jumping teeth under a load. The whole housing is spring-loaded which if adjusted correctly will help the worm ride up & down on the bigger gear. Hope this helps... If not, let me know and I can try again... ;-)
@@jeffrh , yes that really helps however I just want to make sure I understand something as far as diagnosing BL. before I even remove the housing, if I lock the DEC and RA clutches and I try and move the DEC or RA axis with my hands and there is no play or no slop, does this mean I have no backlash? Also, did you ever do a re-greasing of the gears? I read some users are doing that, thank you for an excellent video!!!!!
@@nicholasdisabatino1697 I regrease and set the backlash for both RA & DEC every spring. For me, this helps the guiding. Your main question can be answered in this way. If you guide and are seeing great RMS numbers and your star are round and targets sharp. Then no, I wouldn't mess with this. If you want to check that both the backlash and housing are adjusted correctly. Your going to need to remove that cover. I don't think you can know for sure what the condition that housing is in if you never move it. Gives you a good reason to regrease things...
@@jeffrh I just took a short video of the tension in my DEC belt and worm box.
I think they have slightly too much play but not sure enough to adjust:
www.icloud.com/photos/#0cIhhPoTWOU9a59NG8hkXNaMw
@@nicholasdisabatino1697 Your belt tension is what I have and the housing looks good as well. When you move the housing up & down. You can move the axis in question while doing that. What you will feel is the backlash will get worse and then zero out as your moving the housing. This is normal and shows how the worm is allowed to float on the bigger gear. I hope your guiding improves. There is more to good guiding beside the backlash. Leveling the legs with a carpenters level before putting the head on... Good polar alignment and balance are all items that effects how well your guiding will be. With my CGX, I can get the RMS down to .50 depending on how quickly I set up each night. If I'm in a hurry... My guiding will suffer and those RMS numbers can get to 1.25. Hope all this helps you in your quest for better guiding.
Hi again Jeff
Hope all is aggod with you.
Thanks again for this exceptional video and for all your very kind help to me & others.
Question - as well beinmg able to move either the OTA in Dec or counter weight shaft in RA to check for backlash slop, do you also pay any attention to the noise your mount makes? I notice mine vibrates and shudders less when I have tried to decrease the backlash. I welcome any views / thoughts you have on this. Thanks
If you are hearing something like that then you went to far and the worm can no longer move up & down on the bigger gear. It's binding. Loosen both allens starting with the 2 mm. Then the 3 mm... Move the housing up & down to see that you now have movement over the 2 to 3 mm you would want for the final set up. Now start taking the backlask out with the 3 mm allen. As soon as you feel no more bascklash or movement in RA. That is as far you you need to take things. Any further and you will remove any fee movement the worm needs to float on the bigger gear. When you are happy with the backlash. Move the 2 mm until you have that 2 to 3 mm of housing movement up & down. That should fix you up... You might want to back off the 3mm allen by the smallest amount to be sure that you didn't go to far...
It is sounding like you were to tight and may have also wiped the grease off of the gears. Might be a good time to regrease the bigger gear. You don't need very much. Then run the DC Servo motors to work the grease into the gear and worm. Hope this helps...
@@jeffrh Thanks for that Jeff.
The noise was actually there before I did the adjustment but seemed to get better (less) as I dialed out the backlash a little (turning 3mm anti clock). I'm thinking that if, in my case, the noise *was* due to binding, then taking more backlash out would have caused more binding and more noise but it didn't. So maybe noise from the motors can apply with too backlash and binding? Your thoughts?
The man in the link below had a bad noise from his motors and turned the 3mm adjuster and ithe noise was much improved but I can't see clearly which way he is turning the adjsuter IE whether he is releasing backlash or increasing it a little to release binding....
th-cam.com/video/pvxQ0Ad0s7g/w-d-xo.html
@@HollomanUFOLanding Sounds like you may have a bad worm bearing. Early CGX mount came from the factory with the worm bearing over tightened. It sounds ike you are already out of warrenty? So doing anything to the mount won't effect that... You will need to take the housing off of the mount so you can take the worm assembly off. With that off, you can then loosen the preload on the worm bearing. You can tell you have it right when the worn turns easier with your fingers. There may be a pretty good chance that the bearing was proloaded to tight for to long of a period and will need a new bearing to fix the problem...
Not sure how much Celestron would charge for something like that or if you feel up to the task. How you can tell if you have to much worm bearing preload is you can't turn the worm with your fingers... It is to tight... I have not needed to do this as my mount is only a couple of years old and Celestron fixed this before I got mine. Good luck.
@@jeffrh Hey Jeff
Nope, you were correct in your previous response - I had made it bind. When I was testing the mount, it actually jumped a few times. So I stopped there and then, and, in the dark, removed the dec and ra covers and did it all again.
As per your recommendation, I slackened off the 2mm a bit and then slackened off the 3mm to increase backlash, by turing clockwise. I then slowly turned the 3mm back anti clockwise until I couldn't detect any free play in either axis. I then set the 2mm screw free play to be about 2 to 3mm of movement. I then turned the 3mm a tiny bit clockwise, as per your suggestion, just in case I was slightly over tight.
I retested the mount - no more jumping or weirdness. There is a tiny bit of vibration so I might give the 3mm a tiny final turn clockwise, but apart from that I think (HOPE!) I'm finished - 'til my next adjustment! HAHHA
Thanks again for all your help, so appreciated.
What grade grease do you use? Do you take the factory goop off first before applying new grease? My mounts ( I have 2 CGXLs) are both about 1 year old btw.
@@HollomanUFOLanding I use Super Lube... It's a synthetic grease. You should be able to find it at most Auto Parts stores...
Thank you so much for this great video. It's given me the confidence to adjust the backlash on my CGXL!
Forgive this naive question, but you're actually turning the 3mm Adjustment scew *counter* clockwise, correct, lefty loosey? Is that one of those weird scews that's gets tighter when you turn it to the left, instead of turning it to the right like most screws? Thanks!
Like the name... ;-) Yes, backing the 3mm out lowers the worm closer to the big gear it rides on. This closes the gap and reduces the backlash.
@@jeffrh Thanks! I was just re watching your video as you replied. I'm off outsdie now to give it a go! I'll report back. Thanks again
@@jeffrh Hi Jeff,
Long story short - I made some adjustments and I have my unguided (which I prefer) subs back up to 2 minutes with round stars. ( CGXL 8" Celestron Edge @ F7 1470MM focal length)
I actually spent more time trying to get the *!@#$%^* cover off and on than doing the adjustment! And yes I did lose one of the screws.
Initially, I became lost as to how far I had turned the 3mm Adjustment screw. So I used your method of moving the axis as you turn the scew, RA in my case, and I did this my gently trying to move the counter weight shaft until I encountered no more movement. So that provided me with a 'baseline' of where to adjust from, if that makes sense.
As per your video, once the backlash has been taken out by adjusting the 3mm screw, the motor housing itself is then a bit loose and needs adjusting via the 2mm 'range' screw. I found this to extremely tight but I believe I was able to move it a bit. The movement / recoil on the motor housing is now 2 - 3mm , *but* the mount seems to be tracking well and the subs were up to 2 minute unguided, which is they were before the backlah became an issue.
I noticed last night that I was able to get 2 minuted unguided subs for objects in the west (both circumpolar and otherwise) but in the east 90 seconds was more the sweet spot. Any theory as to why that may be? A balance issue? I believe I have the mount very slightly east side heavy at the momenet.
Thanks again for all your help.
@@HollomanUFOLanding I use a C14 and guide with PHD2. I was getting RMS Errors averaging .5 to .9. with a CGX-L. The big scope gets tossed by the wind catching the Dew Shield some. Still, when the backlash is right. Things will work them selves out in the end. Glad you got your mount working better. Just remember not to get the worm to tight. That is worse than having too much backlash as you are jamming the worm into that bigger gear and you no longer have room for the worm to float on that big gear. Clearskies
@@jeffrh OK thanks. Re your last sentences - that abaility for the worm to float on the bigger gear, that adjustment would be from the 2mm screw that dictates how much the motor unit moves, right? I figured it was better to have some movement there (like I do) rather than hardly any movement.
I have a 14 Edge on another CGXL mount which I'm hoping to have in action soon. I have installed a focus motor and F7 reducer. I have it mounted on a Scope Buggy, which works great. Which targets do you go after using your C14? (Aside from planets.) My RASA covers the big wide field objects. I was thinking of objects like M51, M101 etc for my 14 Edge. Thanks again, & the clearest of skies to you.
Hi Jeff. I did this adjustment on my RA Axis. Got the backlash out as the guiding is much improved. However I could not get the 2mm screw to even move. I could not loosen it nor could I tighten it. Luckily, I didn't get to much additional slop in the motor, so I tested the RA Axis and it works just great. But have you ever seen those 2mm screws so tight you couldn't loosen or tighten them?
I have not. Dumb question coming... ;-) Is there even a 2 mm allen in the hole? My next question would be this, is the mount still in warrenty? If it is, I would send off a note to Celestron and tell them that you backlash is way off. See what they say? You never know till you know. If you are out of warrenty. Try some pentrating spray like WD40. Give it a spray being careful to not soak things other than the 2 mm hole. You may need to take the head off of the mount so you can set it upside down to do this. Let it set overnight. I'm thinking you may have an allen that is stuck from the Blue Loctite they use to help keep the allens from backing in or out. With the head off. Looking down into the 2 mm hole. If you see a lot of blue around the allen. That's most likely the problem. If after an overnight soaking and you can turn the allen. I would take it out to clean up the WD40 and excess Blue Loctite out of the hole. You don't need moch t0 keep the allen from truning on its own. Good luck...
@@jeffrh Hi Jeff. Thanks for the follow up. I too wonder if it's just a little over agressive locktite. I bought a new pair of heavy duty allen wrenchs to see if they can get the bolt lose. The ones I had were cheap and I was just going to bend the wrench if I kept trying to loosen the bolt. Hopefully these with the longer length will give me a little more leverage. But I will be carefull. I'm going to go in and take a real close look as at times I was wondering if the wrench was wedged into the wrong spot. But I'll contact Celestron if I need too. It's about 8 months old. Got last summer. Depending on the target my guiding is between 0.68 and about 1.17 Arc Seconds. at 1422 mm. thanks for the help.
Nice video.
Got my RA really good now but the DEC im having problems with. Cant seem to get enough play in it, way too tight.
Couple of things... Is the belt to tight? You want the belt to have a small amount of up & down motion. .125 to .25" would be good. Or it sounds like you have one of the allens a little to tight. Is the housing able to move up & down? Or is the worm to tight on the bigger gear? Need to know which one it might be to give you a better answer. Thanks...
@@jeffrh Tyvm, i got it in The end but Dec still doesnt behave like The Ra for some reason. When i wrote this The belt tension was part of The problem. I started to treat everything as an balancing act and went back and forth between belt / big allen / small allen instead of just adjusting one at a time and things started to feel better. The mount behaves a little bit better now and no backlash nor any binding that i could notice anyway. Btw i have two maybe not all that related questions If thats ok: Is gear wobble worth addressing? And is The higest point of altitude adjustment(The part over above The locking screws) suposed to have some play to it? The Cgx consists of so many moving parts hehe. I also find it to be The hardest to PA out of all my mounts.
OH, and tyvm for the reply :D
Very Nice of you to take your time and help people!
@@Luftbubblan Gear wobble is another problem all together. That will usually happen because something was to tight. There is no bearing to speak of at the motor end and if that's where the wobble is. You will need to get that fixed. A call to Celestron might be in order and you just might have to order that part.
Once the belt is in the correct tension. You shouldn't need to mess with it while adjusting the backlash. The whole housing is moving to get the backlash set correctly and the belt tension has nothing to do with backlash. If your gear wobble is a result of a worn out part. Then I could be difficult to adjust the backlash as I described in the video. It sounds like you might have an early CGX. If so then I would talk to Celestron about your problem and they just might have a better answer for you than I can give. If your mount is still under warrenty. You do not want to tell them what you did as that will void the warrenty as I stated in the video. All the best....
@@Luftbubblan No problem... About the gear wobble? The Belt gears do have a small amount of wobble to them. Nothing to be concerned over. If you have a warn-out part and the gear is physically lose enough to wobble. That's a problem and you should talk to Celestron about it. You just might get it fixed under warranty. Hope that's a better answer! ;-)
Jeff - Thanks so much. My CGX-L RA stopped working. Opening the cover, I found zero "slop" or "pitch" movement. None. It's too tight. The worm gear is jammed tight against the RA ring. I unscrewed (or screw in) both the 2mm and 3mm adjustment screws, but that caused no "pitch" movement at all. I sense that I need to displace the worm and motor assembly ~1 mm away from the ring gear. Do you know how to achieve that?
-Geoff
Geoff, Sounds like one of the allens moved over time. The 2 MM allen would be counter clockwise to free up the housing. The 3 MM will move the housing in pitch so the the worm can touch the bigger gear. So if both the worm and housing don't move. Loosen the 2 MM counter clockwise and then see if you can get the housing moving up & down. If that works. The move the 3 MM clockwise to get the worm off the big gear. With everything freed up. You can then follow the video to get the backlash zeroed out... Hope this helps...
@@jeffrh Thanks again, Jeff. Today, I detached my RA motor from the belt. Pushing East or West on the hand paddle, I saw the shaft from the motor did not rotate. When I rotated the shaft with my hand, it would start rotating by itself, but then it would stop after ~10 seconds. So, the motor is definitely not functioning well. I have ordered a new one for CGX and CGX-L: Part # CGX-F00-3. Price: $175.00 My fingers are crossed.
@@geoff8205 That's a hard one to take... Sounds like the motor was under to much strain for to long. Hope that fixes you up...
So many CGX/L users have this problem straight from the factory. It makes me think twice about buying Celestron again. Quality assurance is abysmal
DOC, this seems to be a problem with many thing made overseas... At least there is an easy fix though it would be nice if it worked correctly out of the box. Both my CGX and CGX-L track wonderfully when the backlash is set correctly...
Hi Jeff - What I don't understand is Celestron advertises their worm gears in the CGX-L are spring-loaded. Wouldn't this avoid the need to make adjustments?
Thanks - Tommy
Yes and no... You could have one of the adjustment allens back out or in and this will throw the alignment off. My CGX-L came from the dealer with no blue Loctite on the 2 adjustment allens. This allowed them to move on their own and thus misalign the worm to the bigger gear. In my case one of them backed out and I wound up with to much backlash in RA. I put a drop of blue Loctite on 2 and 3 mm allen adjustment screws and my problem was solved. If you are using the mount a lot. The allens can move fairly easiely if they don't hve that Locktite on them.
There was aslo a period where the adjustment of both the RA and Dec were off from the factory... I think Celestron had a bit of a quality control problem which has been remedied. For example, when the CGX first started to be sold. The RA worm bearing was miss adjusted and the worm had trouble turning. This put too much pressure on the bearing which needed to be replaced by Celestron. Sometimes you can get lucky and back off some on the adjustment that holds the bearing and worm together and this fixes that problem. This has also been fixed for at least 4 or 5 years that I know of... Hope this helps...
@@jeffrh
Thanks Jeff. Perfect explanation.
I’m stuck between ordering a new CGX-L or the Sky-Watcher EQ8-R. Decisions decisions. Thanks again!
@@thomasmastrocinque2609 I have the CGX-L and have no trouble with it or the CGX. I needed to keep in family which helps with software loads.
Hey Jeff, can I send you a photo of my graph in the phd2 log viewer. My ra spikes on each side about every 30 seconds and it's killing me when I'm using my c11. I want to get your professional opinion to see if it could be backlash before I void my warranty
Ralph, I have heard others that have had similar problems. This can be from the backlash tightening up over time and when the worm gets to a high spot, it's binding. I have also heard from some that with early CGX mounts, they had the worm bearings set up to tight. Before you go and try this, a call to Celestron might be advised. You can show them that graph and they can let you know whats going on. I would take the free warrenty service over trying something on your own and then finding out that you had another problem. Hope this helps... Celestron isn't as busy because most of their gear is sitting on the ocean somewhere. So turn around time are pretty good right now for service... Happy Holidays!
@@jeffrh. Ok. Thanks Jeff!
Thanks for this Video ,The snail jumps over on my CGX
Just hope it helps you out...
@@jeffrh i hope :-)
@@fuchsfranz4541 Once you figure out what does what... It's very easy to do. You just don't want to go past the point where you start to apply to much pressure on the worm. It still needs to float on the bigger gear.
@@jeffrh Yes i know...
Did you move both clockwise to tighten? I couldn't tell by watching.
Dan, Because of the way I put the housing out of spec. The 3mm allen was counter clockwise and the 2 mm allen was clockwise. This may not be what's needed for everyone when settingthe backlash.
What grease are you using?
Dan, Iused SuperLube...
@@jeffrh I will look for it in our Canadian Tire stores
@@dankahraman354 There or Amazon Canada should have it...
@@jeffrh yes beats using the car which is in the queue for work at car shop. Battery died on Saturday.
@@jeffrh Amazon.ca has Superlube 1) ptfse grease, 2) S1004, 3) 21030 synthetic grease, 4) 51010, 5) multipurpose, 6) teflon, 7) tube 8) spray.... so which one?
3:25 “that’s perfect” 5:04 “that’s perfect”. I can’t see what you are doing either time and why you are saying that.
3:25 I'm turning the 3mm allen to start taking backlash out. 5:04 I'm adjusting the 2mm allen to limit the housing movement to 2 to 3 mm total... Hope that helps...